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Spillover: Animal Infections and the Next Human Pandemic
Ebola, SARS, Hendra, AIDS, and countless other deadly viruses all have one thing in common: the bugs that transmit these diseases all originate in wild animals and pass to humans by a process called spillover. In this gripping account, David Quammen takes the reader along on this astonishing quest to learn how, where from, and why these diseases emerge and asks the terrifying question: What might the next big one be?
592 pages, Paperback
First published September 24, 2012
About the author
David Quammen
65 books1,767 followersDavid Quammen (born February 1948) is an award-winning science, nature and travel writer whose work has appeared in publications such as National Geographic, Outside, Harper's, Rolling Stone, and The New York Times Book Review; he has also written fiction. He wrote a column called "Natural Acts" for Outside magazine for fifteen years. Quammen lives in Bozeman, Montana.
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Displaying 1 - 30 of 2,149 reviews
April 9, 2020
2020 Update: Well, here we go, 2020 Covid pandemic. Don't say David Quammen didn't tell you so. And check out the comments below from 2016. Highlights:
I thought the topic might give me heebie-jeebies, but it mostly didn't, except when it comes to traveling to China, Bangladesh or West Africa. Or working in a disease research lab.
and
I do think SARS was scary as a healthcare provider because it seemed to circumvent standard isolation and had a high fatality rate.
David Quammen is prescient. He appears to have predicted the 2014 Ebola outbreak and ability to country jump years before it happened. Alright, maybe he isn’t a diviner; maybe he merely pays attention to the scientists around him. After all, there’s a reason he is has been given an Academy Award in Literature and is a three-time winner of the National Magazine Award. Spillover: Animal Infections and the Next Human Pandemic explores the science behind human pandemics, and is a culmination of decades-long interest in animals, biology and travel. It is also an intelligent, thoughtful, and occasionally humorous book about the intersection between humans, disease, public health and the animal kingdom.
"Made no mistake; they are connected, these disease outbreaks coming one after another. And they are not simply happening to us; they represent the unintended results of things we are doing. The first crisis is ecological, the second is medical."
The writing is excellent and well-researched, with a list of citations for each chapter. While clearly well versed in biological concepts and the professional scientific field, Quammen writes with an eye to description, creating a liveliness in his stories. When I looked up his biography, it was with no real surprise that I learned he studied William Faulkner on a Rhodes scholarship–like Faulkner, he clearly has a deep love and respect for the natural world. The writing conveys complicated biological concepts in a way that captures the essence without oversimplifying, leaving both the novice and the more knowledgeable reader satisfied. If I have one complaint, it is that the humor present in his short stories isn’t as present; a fitting approach for the somberness of the subject, but I miss it nonetheless. Most of the humor here acknowledges journalistic license but a fair amount relates to the research process:
"If you read the recent scientific literature of disease ecology, which is highly mathematical, and which I do not recommend unless you are deeply interested or troubled with insomnia, you find the basic reproduction rate everywhere."
What takes this book a step beyond the ordinary is that Quammen goes to where the science happens. Interviewing scientists in person, their anecdotes give the research the human touch, and are both instructive and amazing. I found myself deeply wishing my career had taken a different track–but I’m not courageous enough to be a field scientist. The scientists who are looking for the Ebola reservoir are particularly adventuresome: when they collect samples, they do their exploring in full haz-mat gear, including a personal respirator, which leads to interesting challenges. As Quammen summarizes:
"Wait a minute, lemme get this straight: You're in a cave in Uganda, surrounded by Marburg [virus] and rabies and black forest cobras, wading through a slurry of dead bats, getting hit in the face by live ones...the walls are alive with thirsty ticks, and you can hardly breathe, and you can hardly see, and... you've got time to be claustrophobic?'
'Uganda is not famous for its mine rescue teams,' [Amman] said."
Dude. Skydiving and cliff-jumping are for wimps. Trying being a field scientist studying disease.
Just fantastic stuff. If you were ever in doubt about why to get an influenza shot, the information is right here. And why you should be very, very careful about what you eat, particularly game and bushmeat.
**********************************************************
Specific chapter summaries and key points continued at the blog--- just follow under the asterisks
https://clsiewert.wordpress.com/2015/...
I thought the topic might give me heebie-jeebies, but it mostly didn't, except when it comes to traveling to China, Bangladesh or West Africa. Or working in a disease research lab.
and
I do think SARS was scary as a healthcare provider because it seemed to circumvent standard isolation and had a high fatality rate.
David Quammen is prescient. He appears to have predicted the 2014 Ebola outbreak and ability to country jump years before it happened. Alright, maybe he isn’t a diviner; maybe he merely pays attention to the scientists around him. After all, there’s a reason he is has been given an Academy Award in Literature and is a three-time winner of the National Magazine Award. Spillover: Animal Infections and the Next Human Pandemic explores the science behind human pandemics, and is a culmination of decades-long interest in animals, biology and travel. It is also an intelligent, thoughtful, and occasionally humorous book about the intersection between humans, disease, public health and the animal kingdom.
"Made no mistake; they are connected, these disease outbreaks coming one after another. And they are not simply happening to us; they represent the unintended results of things we are doing. The first crisis is ecological, the second is medical."
The writing is excellent and well-researched, with a list of citations for each chapter. While clearly well versed in biological concepts and the professional scientific field, Quammen writes with an eye to description, creating a liveliness in his stories. When I looked up his biography, it was with no real surprise that I learned he studied William Faulkner on a Rhodes scholarship–like Faulkner, he clearly has a deep love and respect for the natural world. The writing conveys complicated biological concepts in a way that captures the essence without oversimplifying, leaving both the novice and the more knowledgeable reader satisfied. If I have one complaint, it is that the humor present in his short stories isn’t as present; a fitting approach for the somberness of the subject, but I miss it nonetheless. Most of the humor here acknowledges journalistic license but a fair amount relates to the research process:
"If you read the recent scientific literature of disease ecology, which is highly mathematical, and which I do not recommend unless you are deeply interested or troubled with insomnia, you find the basic reproduction rate everywhere."
What takes this book a step beyond the ordinary is that Quammen goes to where the science happens. Interviewing scientists in person, their anecdotes give the research the human touch, and are both instructive and amazing. I found myself deeply wishing my career had taken a different track–but I’m not courageous enough to be a field scientist. The scientists who are looking for the Ebola reservoir are particularly adventuresome: when they collect samples, they do their exploring in full haz-mat gear, including a personal respirator, which leads to interesting challenges. As Quammen summarizes:
"Wait a minute, lemme get this straight: You're in a cave in Uganda, surrounded by Marburg [virus] and rabies and black forest cobras, wading through a slurry of dead bats, getting hit in the face by live ones...the walls are alive with thirsty ticks, and you can hardly breathe, and you can hardly see, and... you've got time to be claustrophobic?'
'Uganda is not famous for its mine rescue teams,' [Amman] said."
Dude. Skydiving and cliff-jumping are for wimps. Trying being a field scientist studying disease.
Just fantastic stuff. If you were ever in doubt about why to get an influenza shot, the information is right here. And why you should be very, very careful about what you eat, particularly game and bushmeat.
**********************************************************
Specific chapter summaries and key points continued at the blog--- just follow under the asterisks
https://clsiewert.wordpress.com/2015/...
July 31, 2020
”’Spillover’ is the term used by disease ecologists to denote the moment when a pathogen passes from members of one species, as host, into members of another.”
How does that happen?
”All it required was a mango or water apple tree, laden with ripe fruit, overhanging a pigsty. An infected bat feeds on a water apple, discarding the pulp, which is besmeared with virus; the pulp drops down among the pigs; one pig snarfs it up and gets a good dose of virus; the virus replicates in that pig and passes to others; soon the whole herd is infected and human handlers begin to fall sick.”
Besmeared, doesn’t that give a visual?
So what are we dealing with?
”A zoonosis is an animal infection transmissible to humans. There are more such diseases than you might expect. AIDS is one. Influenza is a whole category of others. Pondering them as a group tends to reaffirm the old Darwinian truth (the darkest of his truths, well known and persistently forgotten) that humanity is a kind of animal, inextricably connected with other animals: in origin and in descent, in sickness and in health. Pondering them individually provides a salubrious reminder that everything, including pestilence, comes from somewhere.”
The thing that I keep thinking about is that coronavirus or Covid-19, because we need to give it a name to distinguish it from all the future coronavirus outbreaks, is just a dress rehearsal for a much bigger theatrical event. From what I’m hearing from health care officials, we are not well prepared. We don’t even have enough masks for health care workers. Did we think it was not going to come here? Did we think it was just a China thing and that air travel wasn’t going to drop it like a rotting fruit basket in every human inhabited region of the world? The symptoms are like getting a cold or the flu; by the time someone knows they have it, they may have infected hundreds of people. ”’Viruses have no locomotion,’ according to the eminent virologist Stephen S. Morse, ‘yet many of them have traveled around the world.’ They can’t run, they can’t walk, they can’t swim, they can’t crawl. They ride.”
The problem with finding a cure is that Covid-19 is an animal infection that has spilled over to humans. Diseases, like polio, that originate in humans are easier to cure. If we eradicate it in humans through inoculations, it disappears. With viruses that spillover from other species, there is what is called a reserve host, such as bats, rats, pigs, or birds, that will incubate the virus, keep it alive, and mutate it. Eradication is impossible.
David Quammen takes us around the world to all the hot spots or, as Richard Preston calls them, the hot zones. You want some vivid, scary writing about Ebola deaths? Pick up Preston’s book. Quammen was interested in traveling to these places to discover how hosting worked with diseases and the exhaustive, frustrating, investigative work that scientists have to do to find these reservoir host creatures. It is dangerous work where a pinprick can kill.
So why are we such a juicy host for invasion by a virus? ”It’s not that they target us especially. It’s that we are so obtrusively, abundantly available. ‘If you look at the world from the point of view of a hungry virus,’ the historian William H. McNeill has noted, ‘or even a bacterium--we offer a magnificent feeding ground with all our billions of human bodies, where, in the recent past, there were only half as many people. In some 25 or 27 years, we have doubled in number. A marvelous target for any organism that can adapt itself to invading us.’”
I might add, at the rate that we are killing off other species of wildlife, aren’t we forcing viruses to spillover to survive?
Quammen provides another stark view of the growth of the human population. ”We are prodigious, we are unprecedented. We are phenomenal. No other primate has ever weighed upon the planet to anything like this degree. In ecological terms, we are almost paradoxical: large-bodied and long-lived but grotesquely abundant. We are the outbreak.”
As I’ve said numerous times in other reviews, the greatest threat to human existence is overpopulation. We don’t need more people. In fact, we need fewer people. Job growth will not keep pace with population increases. We have more value when there are fewer of us. Not to mention, food production will struggle to keep up with rampant population growth, and fresh water will not be able to keep pace either. It makes me think about deer populations when I was growing up on a farm. Whenever they had an explosion in numbers that threatened the ecosystem, an infection would spring up and reduce their numbers. Is the cosmos, at some point, going to decide we need to be reduced?
Quammen’s goal with this book is not to scare people, though he understands that will be a natural reaction to his knee-knocking, inspiring descriptions of the various virus outbreaks that have already happened. He wants us to feel informed, so that we will be more careful and respect the danger of these viruses. We have been lucky so far, and there is no other way to describe it. Combinations of scientists and doctors have reacted quickly to outbreaks around the world, but even they will say they aren’t sure how and why they were able to get ahead of the contagion. Quammen is among the number of scientists who are not wondering if a major pandemic will happen, but when.
My takeaways from this read.
I will no longer be an exotic eater. Whenever I have traveled anywhere in the world, I’ve always been an adventurous eater. Quammen’s descriptions of the live, wild animal markets in China was more than enough to keep me from being curious about what a masked faced civet tastes like or porcupine or an exotic snake. The animals in these markets are treated horribly, and the unsanitary conditions create a perfect environment for producing a spillover.
I am greatly reducing my plane travel. Not out of fear of contagion, but out of respect for the planet. I will say, though, that plane travel will be the modern conveyance that will be the carrier of our destruction. Planes can move people all over the world before they even know they are sick. Quammen mentions that scientists have received pressure to edit from their essays assertions about the dangers of a pandemic traveling by plane. We’ve seen it happen!!!
I will no longer shake people’s hands. I love the historical significance of what a handshake means. By presenting a naked hand, men were showing they were unarmed and meant no harm. Even without a pandemic, how many colds and flus are passed through a handshake? Maybe it is time to dispense with handshakes and replace it with a nod of the head. I certainly don’t want to be responsible for unintentionally making other people sick...potentially terminally sick.
I like the energy of crowds, but as I’ve gotten older, I feel more uncomfortable in large groups of people, and so it will be no great loss for me to avoid crowded events.
I will drive as little as possible. One of the reports in recent days that has made me smile was hearing about the clearing of pollution over cities where people have been asked to stay home. Think if we made a conscious effort, all the time, to reduce our driving time every week. Personally, I’m going to make an effort to condense my errands into one day and as brief an amount of time every week as I can. Let’s give the oil companies a cut in profits.
Times like these are a good time for self-reflection.
Quammen is a vivid and compelling writer who doesn’t indulge himself in hyperbole. He sticks with the facts and gives the reader context without glazing their eyes over. I learned about several viruses that I’ve never heard about and shivered whenever demon viruses I am very familiar with, like Ebola, SARS, or MERS, are mentioned. Oh, and he also mentions another virus. ”The team had electron microscope images of round viral particles, each particle encircled by a corona of knobs.” There’s the current devil we are dealing with.
I want to close the review with an example of Quammen’s ability to make a reader feel like she has been there with his evocative writing.
”Before I knew it, I was helping Lisa Jones-Engel and Gregory Engel trap Macaque monkeys at a shrine in northeastern Bangladesh. We had come to a city called Sylhet, along the banks of the Surma River, an area where the Bangladesh lowlands begin to wrinkle up into hills. The hills rise northward into mountains, beyond which lie Assam, Bhutan, and Tibet. Sylhet is a district capital, home to a half million people and an indeterminate number of other primates. Its streets are flooded with traffic that somehow manages to move despite a near-total absence of stoplights. Hundreds of green motorbike taxis, powered by natural gas, and thousands of brightly decorated bicycle rickshaws, powered by long-suffering men with skinny brown legs, jockey for position alongside the bashed-up busses and creeping cars. In early morning, two-wheeled push carts also roll through the streets, moving vegetables to market. At the bigger intersections loom shopping complexes and upscale hotels behind gleaming glass. It’s a thriving city, one of the richest in this poor country, thanks much to investment and spending by emigrant families, with roots here, who have thrived in Great Britain. They often return home, or at least send money back. Many of the curry shops in London, a man told me, are run by expat Bangladeshis from Sylhet.”
Be smart. Be respectful. Be safe.
Take a moment and watch this short video from Professor Hugh Montgomery about the coronavirus. Thank you, Michael Perkins, for sending this to me. Please share this video with the young people you know who may feel impervious to the flu and don’t fully grasp the greater ramifications. https://www.youtube.com/watch?v=Sg7Rn...
Here is also a short informative video from David Quammen discussing the purpose of this book. https://www.youtube.com/watch?v=qgsqf...
If you wish to see more of my most recent book and movie reviews, visit http://www.jeffreykeeten.com
I also have a Facebook blogger page at:https://www.facebook.com/JeffreyKeeten and an Instagram account https://www.instagram.com/jeffreykeeten/
How does that happen?
”All it required was a mango or water apple tree, laden with ripe fruit, overhanging a pigsty. An infected bat feeds on a water apple, discarding the pulp, which is besmeared with virus; the pulp drops down among the pigs; one pig snarfs it up and gets a good dose of virus; the virus replicates in that pig and passes to others; soon the whole herd is infected and human handlers begin to fall sick.”
Besmeared, doesn’t that give a visual?
So what are we dealing with?
”A zoonosis is an animal infection transmissible to humans. There are more such diseases than you might expect. AIDS is one. Influenza is a whole category of others. Pondering them as a group tends to reaffirm the old Darwinian truth (the darkest of his truths, well known and persistently forgotten) that humanity is a kind of animal, inextricably connected with other animals: in origin and in descent, in sickness and in health. Pondering them individually provides a salubrious reminder that everything, including pestilence, comes from somewhere.”
The thing that I keep thinking about is that coronavirus or Covid-19, because we need to give it a name to distinguish it from all the future coronavirus outbreaks, is just a dress rehearsal for a much bigger theatrical event. From what I’m hearing from health care officials, we are not well prepared. We don’t even have enough masks for health care workers. Did we think it was not going to come here? Did we think it was just a China thing and that air travel wasn’t going to drop it like a rotting fruit basket in every human inhabited region of the world? The symptoms are like getting a cold or the flu; by the time someone knows they have it, they may have infected hundreds of people. ”’Viruses have no locomotion,’ according to the eminent virologist Stephen S. Morse, ‘yet many of them have traveled around the world.’ They can’t run, they can’t walk, they can’t swim, they can’t crawl. They ride.”
The problem with finding a cure is that Covid-19 is an animal infection that has spilled over to humans. Diseases, like polio, that originate in humans are easier to cure. If we eradicate it in humans through inoculations, it disappears. With viruses that spillover from other species, there is what is called a reserve host, such as bats, rats, pigs, or birds, that will incubate the virus, keep it alive, and mutate it. Eradication is impossible.
David Quammen takes us around the world to all the hot spots or, as Richard Preston calls them, the hot zones. You want some vivid, scary writing about Ebola deaths? Pick up Preston’s book. Quammen was interested in traveling to these places to discover how hosting worked with diseases and the exhaustive, frustrating, investigative work that scientists have to do to find these reservoir host creatures. It is dangerous work where a pinprick can kill.
So why are we such a juicy host for invasion by a virus? ”It’s not that they target us especially. It’s that we are so obtrusively, abundantly available. ‘If you look at the world from the point of view of a hungry virus,’ the historian William H. McNeill has noted, ‘or even a bacterium--we offer a magnificent feeding ground with all our billions of human bodies, where, in the recent past, there were only half as many people. In some 25 or 27 years, we have doubled in number. A marvelous target for any organism that can adapt itself to invading us.’”
I might add, at the rate that we are killing off other species of wildlife, aren’t we forcing viruses to spillover to survive?
Quammen provides another stark view of the growth of the human population. ”We are prodigious, we are unprecedented. We are phenomenal. No other primate has ever weighed upon the planet to anything like this degree. In ecological terms, we are almost paradoxical: large-bodied and long-lived but grotesquely abundant. We are the outbreak.”
As I’ve said numerous times in other reviews, the greatest threat to human existence is overpopulation. We don’t need more people. In fact, we need fewer people. Job growth will not keep pace with population increases. We have more value when there are fewer of us. Not to mention, food production will struggle to keep up with rampant population growth, and fresh water will not be able to keep pace either. It makes me think about deer populations when I was growing up on a farm. Whenever they had an explosion in numbers that threatened the ecosystem, an infection would spring up and reduce their numbers. Is the cosmos, at some point, going to decide we need to be reduced?
Quammen’s goal with this book is not to scare people, though he understands that will be a natural reaction to his knee-knocking, inspiring descriptions of the various virus outbreaks that have already happened. He wants us to feel informed, so that we will be more careful and respect the danger of these viruses. We have been lucky so far, and there is no other way to describe it. Combinations of scientists and doctors have reacted quickly to outbreaks around the world, but even they will say they aren’t sure how and why they were able to get ahead of the contagion. Quammen is among the number of scientists who are not wondering if a major pandemic will happen, but when.
My takeaways from this read.
I will no longer be an exotic eater. Whenever I have traveled anywhere in the world, I’ve always been an adventurous eater. Quammen’s descriptions of the live, wild animal markets in China was more than enough to keep me from being curious about what a masked faced civet tastes like or porcupine or an exotic snake. The animals in these markets are treated horribly, and the unsanitary conditions create a perfect environment for producing a spillover.
I am greatly reducing my plane travel. Not out of fear of contagion, but out of respect for the planet. I will say, though, that plane travel will be the modern conveyance that will be the carrier of our destruction. Planes can move people all over the world before they even know they are sick. Quammen mentions that scientists have received pressure to edit from their essays assertions about the dangers of a pandemic traveling by plane. We’ve seen it happen!!!
I will no longer shake people’s hands. I love the historical significance of what a handshake means. By presenting a naked hand, men were showing they were unarmed and meant no harm. Even without a pandemic, how many colds and flus are passed through a handshake? Maybe it is time to dispense with handshakes and replace it with a nod of the head. I certainly don’t want to be responsible for unintentionally making other people sick...potentially terminally sick.
I like the energy of crowds, but as I’ve gotten older, I feel more uncomfortable in large groups of people, and so it will be no great loss for me to avoid crowded events.
I will drive as little as possible. One of the reports in recent days that has made me smile was hearing about the clearing of pollution over cities where people have been asked to stay home. Think if we made a conscious effort, all the time, to reduce our driving time every week. Personally, I’m going to make an effort to condense my errands into one day and as brief an amount of time every week as I can. Let’s give the oil companies a cut in profits.
Times like these are a good time for self-reflection.
Quammen is a vivid and compelling writer who doesn’t indulge himself in hyperbole. He sticks with the facts and gives the reader context without glazing their eyes over. I learned about several viruses that I’ve never heard about and shivered whenever demon viruses I am very familiar with, like Ebola, SARS, or MERS, are mentioned. Oh, and he also mentions another virus. ”The team had electron microscope images of round viral particles, each particle encircled by a corona of knobs.” There’s the current devil we are dealing with.
I want to close the review with an example of Quammen’s ability to make a reader feel like she has been there with his evocative writing.
”Before I knew it, I was helping Lisa Jones-Engel and Gregory Engel trap Macaque monkeys at a shrine in northeastern Bangladesh. We had come to a city called Sylhet, along the banks of the Surma River, an area where the Bangladesh lowlands begin to wrinkle up into hills. The hills rise northward into mountains, beyond which lie Assam, Bhutan, and Tibet. Sylhet is a district capital, home to a half million people and an indeterminate number of other primates. Its streets are flooded with traffic that somehow manages to move despite a near-total absence of stoplights. Hundreds of green motorbike taxis, powered by natural gas, and thousands of brightly decorated bicycle rickshaws, powered by long-suffering men with skinny brown legs, jockey for position alongside the bashed-up busses and creeping cars. In early morning, two-wheeled push carts also roll through the streets, moving vegetables to market. At the bigger intersections loom shopping complexes and upscale hotels behind gleaming glass. It’s a thriving city, one of the richest in this poor country, thanks much to investment and spending by emigrant families, with roots here, who have thrived in Great Britain. They often return home, or at least send money back. Many of the curry shops in London, a man told me, are run by expat Bangladeshis from Sylhet.”
Be smart. Be respectful. Be safe.
Take a moment and watch this short video from Professor Hugh Montgomery about the coronavirus. Thank you, Michael Perkins, for sending this to me. Please share this video with the young people you know who may feel impervious to the flu and don’t fully grasp the greater ramifications. https://www.youtube.com/watch?v=Sg7Rn...
Here is also a short informative video from David Quammen discussing the purpose of this book. https://www.youtube.com/watch?v=qgsqf...
If you wish to see more of my most recent book and movie reviews, visit http://www.jeffreykeeten.com
I also have a Facebook blogger page at:https://www.facebook.com/JeffreyKeeten and an Instagram account https://www.instagram.com/jeffreykeeten/
May 14, 2020
Update At first I thought this book was so relevant to the present coronavirus pandemic crisis in the world, but it's not really as the one thing the book doesn't discuss is what if an animal illness - a bat one, as so many are - is modified or experimented on in a laboratory and it infects a person, who then is patient zero and infects the world? The laboratory connection is not mentioned at all, and therefore the book is not so prescient as many people think, unless you subscribe to the wet market theory.
________________________
This book is a very detailed look at zoonoses, diseases that cross from animals to people. If it hadn't been quite so detailed, it would have been a 10 star. What I have learned:
1. There are three sorts of host. There is the reservoir host that the disease resides in and may or may not cause disease. Then there is the amplification host where if the original host infects it, or if a vector (like fleas that carry it) does, the disease-causing pathogen will multiply to very large numbers. Then there is us! We are often the final host.
2. The biggest natural reservoirs of zoonotic diseases are bats. Especially fruit bats and flying foxes. If you touched a rock that an infected bat did, ate some fruit one shit on, or got bit by the dog that the bat got first, you are at risk. Avoid bats at all cost. Very large numbers of vectors are fleas, mosquitos, flies, lice and ticks.
Now it may seem like bats are more dangerous than other creatures because so many carry diseases but it's not necessarily so. 25% of all mammal species are bats, and it's not known if the y carry the same percentage of zoonoses as other mammal groups or if they really are uniquely dangerous.
Bats breed and live in huge numbers and no one minds if they are caught and their blood sampled or even killed for necropsies. Doing that to, say, large numbers of lions, monkeys, elephants or other much-loved mammals is another issue entirely. But they might be as zoonotic pathogen-ridden as bats, we just don't know. So if you like bats (I do) they should be our friends from a distance.
2. Lyme Disease. If you like rambling in the woods where this is present, choose a year when there haven't been many acorns and go to a big wood rather than a little copse. In little copses there may not be many mammals but there will probably be the white-footed mouse which is a reservoir of the disease. In a good acorn year it will breed like crazy, unchecked. In a bad acorn year, there will be less of them and in a big wood there are many predators for whom they are a major food source. Fleas breed on these mice who are not very good at grooming them away. They bite the deer as they need the blood to breed (much as mosquitos do on us), but are not really relevant in Lyme Disease as just one deer could supply enough blood for millions of ticks to suck on. It is keeping down the sweet little mice that keeps down Lyme Disease in an area.
3. Zoonoses are in general pretty rare, there are only 150 known ones and they don't cause major epidemics these days although they do cause small, limited but extremely newsworthy outbreaks like Ebola, rabies and dengue. Bubonic plague, the Black Death, is a zoonotic disease that was perhaps the worst disease the world has ever faced. But these days, antibiotics cure it quickly.
I've had dengue. There is no treatment for it and it isn't nicknamed bone break disease for nothing. I moved house with it. Easiest move in my life. I just lay there while all around me packed and moved, then they lifted the mattress into the van and transported me to my new house. By the time i was well enough to walk to the bathroom by myself, everything was spick and span. It was about ten days start to finish. Very nasty.
Very interesting book, I had to skim bits at times because it was as detailed and repetitive as a text book although, mostly, considerably less dry. I learned a lot and for that it's definitely a 5 star read.
____________
Notes on reading the book.
________________________
This book is a very detailed look at zoonoses, diseases that cross from animals to people. If it hadn't been quite so detailed, it would have been a 10 star. What I have learned:
1. There are three sorts of host. There is the reservoir host that the disease resides in and may or may not cause disease. Then there is the amplification host where if the original host infects it, or if a vector (like fleas that carry it) does, the disease-causing pathogen will multiply to very large numbers. Then there is us! We are often the final host.
2. The biggest natural reservoirs of zoonotic diseases are bats. Especially fruit bats and flying foxes. If you touched a rock that an infected bat did, ate some fruit one shit on, or got bit by the dog that the bat got first, you are at risk. Avoid bats at all cost. Very large numbers of vectors are fleas, mosquitos, flies, lice and ticks.
Now it may seem like bats are more dangerous than other creatures because so many carry diseases but it's not necessarily so. 25% of all mammal species are bats, and it's not known if the y carry the same percentage of zoonoses as other mammal groups or if they really are uniquely dangerous.
Bats breed and live in huge numbers and no one minds if they are caught and their blood sampled or even killed for necropsies. Doing that to, say, large numbers of lions, monkeys, elephants or other much-loved mammals is another issue entirely. But they might be as zoonotic pathogen-ridden as bats, we just don't know. So if you like bats (I do) they should be our friends from a distance.
2. Lyme Disease. If you like rambling in the woods where this is present, choose a year when there haven't been many acorns and go to a big wood rather than a little copse. In little copses there may not be many mammals but there will probably be the white-footed mouse which is a reservoir of the disease. In a good acorn year it will breed like crazy, unchecked. In a bad acorn year, there will be less of them and in a big wood there are many predators for whom they are a major food source. Fleas breed on these mice who are not very good at grooming them away. They bite the deer as they need the blood to breed (much as mosquitos do on us), but are not really relevant in Lyme Disease as just one deer could supply enough blood for millions of ticks to suck on. It is keeping down the sweet little mice that keeps down Lyme Disease in an area.
3. Zoonoses are in general pretty rare, there are only 150 known ones and they don't cause major epidemics these days although they do cause small, limited but extremely newsworthy outbreaks like Ebola, rabies and dengue. Bubonic plague, the Black Death, is a zoonotic disease that was perhaps the worst disease the world has ever faced. But these days, antibiotics cure it quickly.
I've had dengue. There is no treatment for it and it isn't nicknamed bone break disease for nothing. I moved house with it. Easiest move in my life. I just lay there while all around me packed and moved, then they lifted the mattress into the van and transported me to my new house. By the time i was well enough to walk to the bathroom by myself, everything was spick and span. It was about ten days start to finish. Very nasty.
Very interesting book, I had to skim bits at times because it was as detailed and repetitive as a text book although, mostly, considerably less dry. I learned a lot and for that it's definitely a 5 star read.
____________
Notes on reading the book.
March 20, 2020
I guess I won´t ever take a duck, bat, or cute little monkey as a pet after reading this book. Ok, the ape would be pretty illegal too.
A similar question I kept continually asking myself while reading this: Could it once spread to pets like dogs and cats and back to humans again who infect a bird that infects a bat that is eaten by a wild dog who bites a human etc. Isn´t that an endless circle with possible catastrophes around each corner, even without human intervention such as antibiotic resistance, genetic engineering, and biological warfare?
And what if the mutation rate of the viruses reaches a level that it gets impossible to develop vaccines, because their genetic code changes so quickly over a few months that there is no cure anymore or the get immune within weeks.
It can´t be overemphasized enough that we know close to nothing, that no serious predictions are possible because:
There are not just the already mutating RNA viruses around, but many we don´t know enough about and still have to do basic research.
There are species we still haven´t discovered.
Microorganisms interact, swap, infiltrate another and the ones successful are the winners of a hundreds of millions year long arms race and were able to adapt to ever more complex lifeforms, possibly enabling higher life.
There are more and more interactions between primates, rodents, and other species and humans due to natural destruction and population growth.
We don´t know how quickly viruses can evolve, jump from species to species, become less harmful or a killer for everyone, as each one infected could become the patient zero for a much deadlier version of the original virus. What if the person has HIV, tuberculosis, or hepatitis C and the virus combines its abilities with the ones of the chronic illness, let´s say the flu with AIDS?
It´s Russian roulette to eat, and live next to, primates who share up to 97 to 98 percent of the same genome.
We will (or already have been) be breeding hybrids and human ape chimeras.
Many of the worst diseases such as Ebola, BSE, Bubonic plague, anthrax, AIDS, influenza, Hantavirus, leprosy, rabies, zika, and many others are zoonosis, such as SARS Cov-2, and as soon as they have spread widely enough in populations or even around the world, they will last forever. As each human is unique and RNA Viruses are really bad, there will always be reservoirs of hosts until the next winter is coming.
It´s already enough to touch anything invisibly contaminated with any body fluid of a bat, monkey, or whatever. Human, of course, too.
There are different stages with different hosts, be it animals or humans, getting sick or not getting sick, transmitting the disease.
We are isolating ourselves more and more from nature, have more allergies, get sicker with all the civilization diseases and make ourselves much more vulnerable to new viruses, as our immune systems aren´t used to get in contact with dirt and germs anymore and the bacterias and viruses that survive are more hardcore.
What happens if flying syringes, escaped lab animals, and all the genetically engineered crops and animals we have already left out into the world interact with the microflora, and the invisible monsters take interesting power ups we integrated to grow more meat and resistant plants for themselves?
The incompetence of politicians and governments, especially in this really very important field, is shocking and would be as ridiculous as all they do to simulate doing anything, if it wouldn´t be so dangerous. They even aren´t able to follow plans that have been finetuned over decades for the case of a pandemic. It´s as if they were even too stupid to read simple instructions or hand them to one of their hundreds of assistants.
The basic reproduction rate, virulence, case fatality rate, pathogenicity, and other factors are black swans, coincidences, nobody knows what will and can happen, it´s a question of good or bad luck if it gets deadlier or harmless, any person infected could be the starting point for a mutation to kill hundreds of millions.
I didn´t realize how many terrible diseases came out of the animal kingdom, but now it makes perfect sense that a new land without police knowing the enemy is a dreamland for each new virus and a human has pretty many functions to mess with. That tropical countries are so overstuffed with potentially deadly dangers is one more of the reasons why I am a stay at home guy, I mean, if it doesn´t directly kill one, one could bring undetectable, new death home from the jungle without even recognizing it.
Quammen didn´t directly predict the 2013 Ebola
https://en.wikipedia.org/wiki/Western...
and 2020 Coronavirus
https://en.wikipedia.org/wiki/2019%E2...
epidemic, but he explained in detail that more and more people in an interconnected, globalized world in much contact with wild animals may lead to unforeseeable chain reactions.
These scientists researching and studying outside in the field, taking the probes, working in biosafety level 4 labs, are so badass and courageous to provide the knowledge needed to find cures for these plagues that it´s hard to imagine how one normal person should do that. I would get so paranoid and nervous that it wouldn´t end well.
The too specific biological aspects of the book can be skimmed and scanned if one isn´t into this kind of stuff, but the great and vivid style of telling the stories surrounding the facts will be terrifying for every reader.
We are ourselves permanently breeding the next angel of death by adding genetic engineering, poisoning nature, developing more and more drugs and chemicals that are used in vast amounts without knowing the short, not even to speak of the long, time effects, antibiotic resistance, and biological warfare. They really tried to make ebolapox, as if diseases like AIDS or SARS weren´t horrible enough and it´s a question of a coincidence if the next big plague will be all natural, made by ignorance and involuntary bad luck coincidences, or by an oopsie in a secret military biohazard level 4 umbrella corporation lab with this song in the background.
https://www.youtube.com/watch?v=9L7mZ...
Could be used for a black comedy scene too…
Would also be quite an irony if the majority of the human population is wiped out in an attempt to find a cure for cancer or the path to immortality.
Since the outbreak of SARS Cov-2, I am repeatedly thinking of the game Plague Inc. I wasted pretty much lifetime with. And yes, before you ask, I was very successful.
https://www.youtube.com/watch?v=pSat_...
https://www.youtube.com/watch?v=wMxuZ...
A wiki walk can be as refreshing to the mind as a walk through nature in this completely overrated real life outside books:
https://en.wikipedia.org/wiki/Zoonosis
https://en.wikipedia.org/wiki/Virulence
https://en.wikipedia.org/wiki/Basic_r....
https://en.wikipedia.org/wiki/Case_fa...
https://en.wikipedia.org/wiki/Pathoge...
https://en.wikipedia.org/wiki/Flying_...
https://en.wikipedia.org/wiki/List_of...
https://en.wikipedia.org/wiki/Biosafe...
Some links dealing with the current pandemic:
CNN live updates
https://edition.cnn.com/asia/live-new...
John Hopkins CSSE world map
https://gisanddata.maps.arcgis.com/ap...
Youtube statistics
https://www.youtube.com/watch?v=qgylp...
A similar question I kept continually asking myself while reading this: Could it once spread to pets like dogs and cats and back to humans again who infect a bird that infects a bat that is eaten by a wild dog who bites a human etc. Isn´t that an endless circle with possible catastrophes around each corner, even without human intervention such as antibiotic resistance, genetic engineering, and biological warfare?
And what if the mutation rate of the viruses reaches a level that it gets impossible to develop vaccines, because their genetic code changes so quickly over a few months that there is no cure anymore or the get immune within weeks.
It can´t be overemphasized enough that we know close to nothing, that no serious predictions are possible because:
There are not just the already mutating RNA viruses around, but many we don´t know enough about and still have to do basic research.
There are species we still haven´t discovered.
Microorganisms interact, swap, infiltrate another and the ones successful are the winners of a hundreds of millions year long arms race and were able to adapt to ever more complex lifeforms, possibly enabling higher life.
There are more and more interactions between primates, rodents, and other species and humans due to natural destruction and population growth.
We don´t know how quickly viruses can evolve, jump from species to species, become less harmful or a killer for everyone, as each one infected could become the patient zero for a much deadlier version of the original virus. What if the person has HIV, tuberculosis, or hepatitis C and the virus combines its abilities with the ones of the chronic illness, let´s say the flu with AIDS?
It´s Russian roulette to eat, and live next to, primates who share up to 97 to 98 percent of the same genome.
We will (or already have been) be breeding hybrids and human ape chimeras.
Many of the worst diseases such as Ebola, BSE, Bubonic plague, anthrax, AIDS, influenza, Hantavirus, leprosy, rabies, zika, and many others are zoonosis, such as SARS Cov-2, and as soon as they have spread widely enough in populations or even around the world, they will last forever. As each human is unique and RNA Viruses are really bad, there will always be reservoirs of hosts until the next winter is coming.
It´s already enough to touch anything invisibly contaminated with any body fluid of a bat, monkey, or whatever. Human, of course, too.
There are different stages with different hosts, be it animals or humans, getting sick or not getting sick, transmitting the disease.
We are isolating ourselves more and more from nature, have more allergies, get sicker with all the civilization diseases and make ourselves much more vulnerable to new viruses, as our immune systems aren´t used to get in contact with dirt and germs anymore and the bacterias and viruses that survive are more hardcore.
What happens if flying syringes, escaped lab animals, and all the genetically engineered crops and animals we have already left out into the world interact with the microflora, and the invisible monsters take interesting power ups we integrated to grow more meat and resistant plants for themselves?
The incompetence of politicians and governments, especially in this really very important field, is shocking and would be as ridiculous as all they do to simulate doing anything, if it wouldn´t be so dangerous. They even aren´t able to follow plans that have been finetuned over decades for the case of a pandemic. It´s as if they were even too stupid to read simple instructions or hand them to one of their hundreds of assistants.
The basic reproduction rate, virulence, case fatality rate, pathogenicity, and other factors are black swans, coincidences, nobody knows what will and can happen, it´s a question of good or bad luck if it gets deadlier or harmless, any person infected could be the starting point for a mutation to kill hundreds of millions.
I didn´t realize how many terrible diseases came out of the animal kingdom, but now it makes perfect sense that a new land without police knowing the enemy is a dreamland for each new virus and a human has pretty many functions to mess with. That tropical countries are so overstuffed with potentially deadly dangers is one more of the reasons why I am a stay at home guy, I mean, if it doesn´t directly kill one, one could bring undetectable, new death home from the jungle without even recognizing it.
Quammen didn´t directly predict the 2013 Ebola
https://en.wikipedia.org/wiki/Western...
and 2020 Coronavirus
https://en.wikipedia.org/wiki/2019%E2...
epidemic, but he explained in detail that more and more people in an interconnected, globalized world in much contact with wild animals may lead to unforeseeable chain reactions.
These scientists researching and studying outside in the field, taking the probes, working in biosafety level 4 labs, are so badass and courageous to provide the knowledge needed to find cures for these plagues that it´s hard to imagine how one normal person should do that. I would get so paranoid and nervous that it wouldn´t end well.
The too specific biological aspects of the book can be skimmed and scanned if one isn´t into this kind of stuff, but the great and vivid style of telling the stories surrounding the facts will be terrifying for every reader.
We are ourselves permanently breeding the next angel of death by adding genetic engineering, poisoning nature, developing more and more drugs and chemicals that are used in vast amounts without knowing the short, not even to speak of the long, time effects, antibiotic resistance, and biological warfare. They really tried to make ebolapox, as if diseases like AIDS or SARS weren´t horrible enough and it´s a question of a coincidence if the next big plague will be all natural, made by ignorance and involuntary bad luck coincidences, or by an oopsie in a secret military biohazard level 4 umbrella corporation lab with this song in the background.
https://www.youtube.com/watch?v=9L7mZ...
Could be used for a black comedy scene too…
Would also be quite an irony if the majority of the human population is wiped out in an attempt to find a cure for cancer or the path to immortality.
Since the outbreak of SARS Cov-2, I am repeatedly thinking of the game Plague Inc. I wasted pretty much lifetime with. And yes, before you ask, I was very successful.
https://www.youtube.com/watch?v=pSat_...
https://www.youtube.com/watch?v=wMxuZ...
A wiki walk can be as refreshing to the mind as a walk through nature in this completely overrated real life outside books:
https://en.wikipedia.org/wiki/Zoonosis
https://en.wikipedia.org/wiki/Virulence
https://en.wikipedia.org/wiki/Basic_r....
https://en.wikipedia.org/wiki/Case_fa...
https://en.wikipedia.org/wiki/Pathoge...
https://en.wikipedia.org/wiki/Flying_...
https://en.wikipedia.org/wiki/List_of...
https://en.wikipedia.org/wiki/Biosafe...
Some links dealing with the current pandemic:
CNN live updates
https://edition.cnn.com/asia/live-new...
John Hopkins CSSE world map
https://gisanddata.maps.arcgis.com/ap...
Youtube statistics
https://www.youtube.com/watch?v=qgylp...
October 17, 2012
You have to understand. I have my phobias. So it makes for awkward social encounters. Like: “Mommy,” said the little girl in the elevator, “Why is that man holding his breath the whole way down from the 16th floor?” I have been known to say things like, “Will you please stop sneezing in the direction of my beer?” I went to a doctor’s office a few years ago. Nothing ultimately serious, but possibly so, so that I went for the quickly scheduled appointment even though I was already nursing a bad cold. He wouldn’t have to touch my face, I safely predicted. It was a doctor I had never seen before, and after the usual 15-minute wait in solitary, he came in to the examination room with a game show-host smile and extended his hand, like, you know, we were soon to become new best friends. So I put up my hands defensively and said, “Sorry, but I have a cold and it’s better not to shake hands.” I figured, as a doctor, he would appreciate my candor and consideration for him and the many patients to follow. Well, he kept his hand out for a minute, as if I had slapped him, clearly thinking about what I had said. Then, with a busy officiousness, he strode to the sink and vigorously washed his hands with some anti-bacterial goo. This gave me pause. Why was he washing his hands after I declined shaking his hand and not before he offered it?
I share this because the last thing I really need is to read a book about Animal Infections and the Next Human Pandemic. Like going to see an obvious Horror movie, I know I will be scared. Yet, we plunk down our money, watch the predictable script and wait for the creepy Pavlovian organ music to raise the hair on the back of our necks. So, scare me shitless, David Quammen. I gots to know.
It is not until page 511 of this 520-page book that Quammen raises the question that he is often asked by those learning he is writing such a book: “Are we all gonna die?” And the answer is: Yes, we’re all gonna die. Yes. We are all gonna pay taxes and we are all gonna die. Most of us, though, will probably die of something more mundane than a new virus lately emerged from a duck or a chimpanzee or a bat.
Most, but not all of us.
This is a book about zoonosis, animal infections transmissible to humans. AIDS is one. Rabies. Ebola. Marburg. Influenza. Beware the animal reservoir. That would be the animal that ‘hosts’ the virus, safely unto itself, but potentially lethal when it jumps, when there’s a Spillover to humans. So don’t nosh on raw monkey or ape bushmeat, no matter how prized that delicacy is in the culture you’re visiting. Don’t place your pigsty under the mango tree. And don’t under any circumstances drink the palm sap. If you happen to crawl into an African cave, you know, for the experience of being underground with stale air, no natural light, thousands of bats peeing on you from above and a few cobras slinking through your feet, all without a biohazard suit, do not under any circumstances reach down for balance and touch the bat guano with your bare hand. Trust me, bad shit happens.
I learned more reading this book than I did in two semesters of indifferently-attended college biology classes. Not that I can articulate the difference between microbiology and molecular biology, or other things unnecessary to get through the day. But how about this? Of all the mammals in the world – every dog, every deer, every kittycat – every freaking mammal, one in four is a bat. That’s: 1) a lot of bats ; and 2) a bad thing. Also, if you go to the Dominican Republic or some other exotic island and one of the locals comes along the beach to put a macaque on your head for a cute picture to send home to the family, resist the tourist urge. You may be bringing home something more than a Kodak moment.
Quammen has found the right level of transmission to get these notions of science and math across to an idiot like me. And, even if I failed him, I was nevertheless entertained.
Here is the way to start a chapter:
In late February, 2003, SARS got on a plane in Hong Kong and went to Toronto. But soon we are learning more about bats, three species in particular carrying SARS-like virus: the big-eared horseshoe bat, the least horseshoe bat, and Pearson’s Horseshoe bat. Waxing smart-alecky, Quammen quips, “If you ever notice these animals on the menu of a restaurant in Southern China, you might want to choose the noodles instead.
But I like smart-alecky.
So I was scared, entertained and enlightened. Sometimes a single sentence would send me happily to both a dictionary and Google, such as this description of his first meeting with a researcher in Guangzhou: I suppose the durian should have been my first signal that he was a temerarious eater.
One last, lingering piece of advice I will share:
If your husband catches an ebolavirus, give him food and water and love and prayers but keep your distance, wait patiently, hope for the best—and, if he dies, don’t clean out his bowels by hand. Better to step back, blow a kiss, and burn the hut.
Wise words. Which I pass along, like a reservoir host, as a public service.
I share this because the last thing I really need is to read a book about Animal Infections and the Next Human Pandemic. Like going to see an obvious Horror movie, I know I will be scared. Yet, we plunk down our money, watch the predictable script and wait for the creepy Pavlovian organ music to raise the hair on the back of our necks. So, scare me shitless, David Quammen. I gots to know.
It is not until page 511 of this 520-page book that Quammen raises the question that he is often asked by those learning he is writing such a book: “Are we all gonna die?” And the answer is: Yes, we’re all gonna die. Yes. We are all gonna pay taxes and we are all gonna die. Most of us, though, will probably die of something more mundane than a new virus lately emerged from a duck or a chimpanzee or a bat.
Most, but not all of us.
This is a book about zoonosis, animal infections transmissible to humans. AIDS is one. Rabies. Ebola. Marburg. Influenza. Beware the animal reservoir. That would be the animal that ‘hosts’ the virus, safely unto itself, but potentially lethal when it jumps, when there’s a Spillover to humans. So don’t nosh on raw monkey or ape bushmeat, no matter how prized that delicacy is in the culture you’re visiting. Don’t place your pigsty under the mango tree. And don’t under any circumstances drink the palm sap. If you happen to crawl into an African cave, you know, for the experience of being underground with stale air, no natural light, thousands of bats peeing on you from above and a few cobras slinking through your feet, all without a biohazard suit, do not under any circumstances reach down for balance and touch the bat guano with your bare hand. Trust me, bad shit happens.
I learned more reading this book than I did in two semesters of indifferently-attended college biology classes. Not that I can articulate the difference between microbiology and molecular biology, or other things unnecessary to get through the day. But how about this? Of all the mammals in the world – every dog, every deer, every kittycat – every freaking mammal, one in four is a bat. That’s: 1) a lot of bats ; and 2) a bad thing. Also, if you go to the Dominican Republic or some other exotic island and one of the locals comes along the beach to put a macaque on your head for a cute picture to send home to the family, resist the tourist urge. You may be bringing home something more than a Kodak moment.
Quammen has found the right level of transmission to get these notions of science and math across to an idiot like me. And, even if I failed him, I was nevertheless entertained.
Here is the way to start a chapter:
In late February, 2003, SARS got on a plane in Hong Kong and went to Toronto. But soon we are learning more about bats, three species in particular carrying SARS-like virus: the big-eared horseshoe bat, the least horseshoe bat, and Pearson’s Horseshoe bat. Waxing smart-alecky, Quammen quips, “If you ever notice these animals on the menu of a restaurant in Southern China, you might want to choose the noodles instead.
But I like smart-alecky.
So I was scared, entertained and enlightened. Sometimes a single sentence would send me happily to both a dictionary and Google, such as this description of his first meeting with a researcher in Guangzhou: I suppose the durian should have been my first signal that he was a temerarious eater.
One last, lingering piece of advice I will share:
If your husband catches an ebolavirus, give him food and water and love and prayers but keep your distance, wait patiently, hope for the best—and, if he dies, don’t clean out his bowels by hand. Better to step back, blow a kiss, and burn the hut.
Wise words. Which I pass along, like a reservoir host, as a public service.
March 3, 2023
Another pandemic is on the way. The destruction of the Amazon has unleashed all sorts of deadly microbes. One scientist calls it shaking the trees.
===============
Why Covid-19 is always one step ahead of the US response
https://www.vox.com/coronavirus-covid...
==========
The watchword: early detection, early action.
“Spillover” is the term used by disease ecologists to denote the moment when a pathogen passes from members of one species, as host, into members of another.
This Coronavirus is what the book "Spillover" calls zoonotic. In this case, the Chinese peasant farmers literally live with their animals which are carriers of these exotic viruses that they are immune to, but pass on to humans who are not immune. The viruses incubate and mutate in the humans and are transmittable to other humans. Apparently this new one, Covid-19, is easily transmittable, but it's different enough from others we have seen that it takes awhile to figure it out. Old remedies and vaccines don't work. Our increased trade and business with China in recent decades has meant that numerous potential carriers from the U.S. are constantly flying back and forth and bringing the virus to our shores. It's no surprise that the West Coast has the most cases.
===========
I'm a doctor's kid. My father told me more than once that when he was 10 years old (1927) he read a book titled "Microbe Hunters" by Paul de Kruif that inspired him to become a medical doctor. In spite of the Great Depression and WW II, he achieved his goal. Another book he passed on to me was "Rats, Lice, and History" by Hans Zinsser. I did not become an MD myself, but have retained my father's interest in epidemiology (which also extends to an interest in genetics and cancer).
The author quotes Zinsser....
“Here, as in bacterial disease, there is a lively interchange of parasites between man and the animal world.” Zinsser was a panoramic thinker as well as an acutely trained microbiologist. Eight decades ago he sensed that viruses, only lately discovered, might be among the most nefarious of zoonoses."
Among zoonotic diseases are monkeypox, bovine tuberculosis, Lyme disease, West Nile fever, Marburg virus disease, rabies, hantavirus pulmonary syndrome, anthrax, Lassa fever, Rift Valley fever, ocular larva migrans, scrub typhus, Bolivian hemorrhagic fever, Kyasanur forest disease, and a strange new affliction called Nipah encephalitis, which has killed pigs and pig farmers in Malaysia.
This form of interspecies leap is common, not rare; about 60 percent of all human infectious diseases currently known either cross routinely or have recently crossed between other animals and us. Ecological disturbance causes such diseases to emerge. Such was the case with gold miners in Gabon (and their families— these camps were essentially villages) by their very presence, their needs for food, shelter, and fuel, had caused disturbance to the forest canopy and the creatures that lived in it. The miners ate Ebola-infected chimpanzees and gorillas and spread the disease to other humans.
=========
When and where did it start, this modern era of emerging zoonotic diseases? A good candidate would be the emergence of Machupo virus among Bolivian villagers between 1959 and 1963. Symptoms included fever and chills, nausea and vomiting, body aches, nosebleeds, and bleeding gums. It became known as El Tifu Negro (the Black Typhus, for the color of vomit and stool).
If you assembled a short list of the highlights and high anxieties of that saga within recent decades, it could include not just Machupo but also Marburg (1967), Lassa (1969), Ebola (1976), HIV-1 (inferred in 1981, first isolated in 1983), HIV-2 (1986), Sin Nombre (1993), Hendra (1994), avian flu (1997), Nipah (1998), West Nile (1999), and SARS (2003). Swine flu-H1N1 (2009) did not prove as deadly as feared.
A person might construe this list as a sequence of dire but unrelated events— independent misfortunes that have happened to us, to humans, for one unfathomable reason and another. Seen that way, Machupo and the HIVs and SARS and the others are “acts of God” in the figurative (or literal) sense, grievous mishaps of a kind with earthquakes and volcanic eruptions and meteor impacts, which can be lamented and ameliorated but not avoided. That’s a passive, almost stoical way of viewing them. It’s also the wrong way.
Make no mistake, they are connected, these disease outbreaks coming one after another. And they are not simply happening to us; they represent the unintended results of things we are doing. Human-caused ecological pressures and disruptions are bringing animal pathogens ever more into contact with human populations, while human technology and behavior are spreading those pathogens ever more widely and quickly.
Students of virology now speak of the “virosphere,” a vast realm of organisms that probably dwarfs every other group. Now the disruption of natural ecosystems seems more and more to be unloosing such microbes into a wider world. Many viruses, for instance, inhabit the forests of Central Africa, each parasitic host a kind of bacterium or animal or fungus or protist or plant. Viruses can only replicate inside the living cells of some other organism. Commonly they inhabit one kind of animal or plant, with whom their relations are intimate, ancient, and often (but not always) commensal. That is to say, dependent but benign. But now the disruption of natural ecosystems seems more and more to be unloosing such microbes into a wider world.
Viruses, especially those of a certain sort— those whose genomes consist of RNA rather than DNA, leaving them more prone to mutation— are highly and rapidly adaptive. All these factors have yielded not just novel infections and dramatic little outbreaks, but also new epidemics and pandemics.
================
The nature of the current vaccines....
https://www.youtube.com/watch?v=mvA9g...
==================
"If you’re a thriving population, living at high density but exposed to new bugs, it’s just a matter of time until the Next Big One (NBO) arrives."
Examples of NBO from the book....
AIDS: about 30 million deaths, 34 million living people now infected, with no end in sight.
Polio in America
Smallpox in the Americas arriving from Spain in 1520
The Black Death: 1347-1352, killing 30% of the people who lived in Europe (attributable to bubonic plague)
The 1918–1919 influenza--the first H1N1 pandemic--"which had its ultimate source in a wild aquatic bird and, after passing through some combination of domesticated animals, emerged to kill as many as 50 million."
===========
The next step was constructing a family tree of all influenza strains that have circulated since 1918. Reviewing the evidence in 2009, three of the world’s leading infectious disease specialists – David Morens, Jeffery Taubenberger, and Anthony Fauci – concluded:
It is remarkable not only that direct ‘all-eight-gene’ descendants of the 1918 virus still circulate in humans as epidemic H1N1 viruses and in swine as epizootic H1N1 viruses, but also that for the last 50 years the original virus and its progeny have continually donated genes to new viruses to cause pandemics, epidemics and epizootics. The novel H1N1 virus associated with the ongoing 2009 pandemic is a fourth-generation descendant of the 1918 virus.
That is a chilling conclusion that compels us to rethink the life history of the disease. In fact the 1918 influenza didn’t disappear at all. Instead, the last hundred-plus years of influenza can best be understood as a single pandemic.
We are falling sick and dying every winter from the viral harvest of that Great War, because the viral progeny of the 1918 pandemic influenza are still with us, reaping their seasonal toll and occasionally recombining to generate a pandemic.
more on that....
https://thebaffler.com/latest/the-unw...
=========
Marcel Proust's father was a trailblazing epidemiologist who helped get cholera under control in Western Europe. It's a great story.
https://thelandofdesire.substack.com/...
===============
Why Covid-19 is always one step ahead of the US response
https://www.vox.com/coronavirus-covid...
==========
The watchword: early detection, early action.
“Spillover” is the term used by disease ecologists to denote the moment when a pathogen passes from members of one species, as host, into members of another.
This Coronavirus is what the book "Spillover" calls zoonotic. In this case, the Chinese peasant farmers literally live with their animals which are carriers of these exotic viruses that they are immune to, but pass on to humans who are not immune. The viruses incubate and mutate in the humans and are transmittable to other humans. Apparently this new one, Covid-19, is easily transmittable, but it's different enough from others we have seen that it takes awhile to figure it out. Old remedies and vaccines don't work. Our increased trade and business with China in recent decades has meant that numerous potential carriers from the U.S. are constantly flying back and forth and bringing the virus to our shores. It's no surprise that the West Coast has the most cases.
===========
I'm a doctor's kid. My father told me more than once that when he was 10 years old (1927) he read a book titled "Microbe Hunters" by Paul de Kruif that inspired him to become a medical doctor. In spite of the Great Depression and WW II, he achieved his goal. Another book he passed on to me was "Rats, Lice, and History" by Hans Zinsser. I did not become an MD myself, but have retained my father's interest in epidemiology (which also extends to an interest in genetics and cancer).
The author quotes Zinsser....
“Here, as in bacterial disease, there is a lively interchange of parasites between man and the animal world.” Zinsser was a panoramic thinker as well as an acutely trained microbiologist. Eight decades ago he sensed that viruses, only lately discovered, might be among the most nefarious of zoonoses."
Among zoonotic diseases are monkeypox, bovine tuberculosis, Lyme disease, West Nile fever, Marburg virus disease, rabies, hantavirus pulmonary syndrome, anthrax, Lassa fever, Rift Valley fever, ocular larva migrans, scrub typhus, Bolivian hemorrhagic fever, Kyasanur forest disease, and a strange new affliction called Nipah encephalitis, which has killed pigs and pig farmers in Malaysia.
This form of interspecies leap is common, not rare; about 60 percent of all human infectious diseases currently known either cross routinely or have recently crossed between other animals and us. Ecological disturbance causes such diseases to emerge. Such was the case with gold miners in Gabon (and their families— these camps were essentially villages) by their very presence, their needs for food, shelter, and fuel, had caused disturbance to the forest canopy and the creatures that lived in it. The miners ate Ebola-infected chimpanzees and gorillas and spread the disease to other humans.
=========
When and where did it start, this modern era of emerging zoonotic diseases? A good candidate would be the emergence of Machupo virus among Bolivian villagers between 1959 and 1963. Symptoms included fever and chills, nausea and vomiting, body aches, nosebleeds, and bleeding gums. It became known as El Tifu Negro (the Black Typhus, for the color of vomit and stool).
If you assembled a short list of the highlights and high anxieties of that saga within recent decades, it could include not just Machupo but also Marburg (1967), Lassa (1969), Ebola (1976), HIV-1 (inferred in 1981, first isolated in 1983), HIV-2 (1986), Sin Nombre (1993), Hendra (1994), avian flu (1997), Nipah (1998), West Nile (1999), and SARS (2003). Swine flu-H1N1 (2009) did not prove as deadly as feared.
A person might construe this list as a sequence of dire but unrelated events— independent misfortunes that have happened to us, to humans, for one unfathomable reason and another. Seen that way, Machupo and the HIVs and SARS and the others are “acts of God” in the figurative (or literal) sense, grievous mishaps of a kind with earthquakes and volcanic eruptions and meteor impacts, which can be lamented and ameliorated but not avoided. That’s a passive, almost stoical way of viewing them. It’s also the wrong way.
Make no mistake, they are connected, these disease outbreaks coming one after another. And they are not simply happening to us; they represent the unintended results of things we are doing. Human-caused ecological pressures and disruptions are bringing animal pathogens ever more into contact with human populations, while human technology and behavior are spreading those pathogens ever more widely and quickly.
Students of virology now speak of the “virosphere,” a vast realm of organisms that probably dwarfs every other group. Now the disruption of natural ecosystems seems more and more to be unloosing such microbes into a wider world. Many viruses, for instance, inhabit the forests of Central Africa, each parasitic host a kind of bacterium or animal or fungus or protist or plant. Viruses can only replicate inside the living cells of some other organism. Commonly they inhabit one kind of animal or plant, with whom their relations are intimate, ancient, and often (but not always) commensal. That is to say, dependent but benign. But now the disruption of natural ecosystems seems more and more to be unloosing such microbes into a wider world.
Viruses, especially those of a certain sort— those whose genomes consist of RNA rather than DNA, leaving them more prone to mutation— are highly and rapidly adaptive. All these factors have yielded not just novel infections and dramatic little outbreaks, but also new epidemics and pandemics.
================
The nature of the current vaccines....
https://www.youtube.com/watch?v=mvA9g...
==================
"If you’re a thriving population, living at high density but exposed to new bugs, it’s just a matter of time until the Next Big One (NBO) arrives."
Examples of NBO from the book....
AIDS: about 30 million deaths, 34 million living people now infected, with no end in sight.
Polio in America
Smallpox in the Americas arriving from Spain in 1520
The Black Death: 1347-1352, killing 30% of the people who lived in Europe (attributable to bubonic plague)
The 1918–1919 influenza--the first H1N1 pandemic--"which had its ultimate source in a wild aquatic bird and, after passing through some combination of domesticated animals, emerged to kill as many as 50 million."
===========
The next step was constructing a family tree of all influenza strains that have circulated since 1918. Reviewing the evidence in 2009, three of the world’s leading infectious disease specialists – David Morens, Jeffery Taubenberger, and Anthony Fauci – concluded:
It is remarkable not only that direct ‘all-eight-gene’ descendants of the 1918 virus still circulate in humans as epidemic H1N1 viruses and in swine as epizootic H1N1 viruses, but also that for the last 50 years the original virus and its progeny have continually donated genes to new viruses to cause pandemics, epidemics and epizootics. The novel H1N1 virus associated with the ongoing 2009 pandemic is a fourth-generation descendant of the 1918 virus.
That is a chilling conclusion that compels us to rethink the life history of the disease. In fact the 1918 influenza didn’t disappear at all. Instead, the last hundred-plus years of influenza can best be understood as a single pandemic.
We are falling sick and dying every winter from the viral harvest of that Great War, because the viral progeny of the 1918 pandemic influenza are still with us, reaping their seasonal toll and occasionally recombining to generate a pandemic.
more on that....
https://thebaffler.com/latest/the-unw...
=========
Marcel Proust's father was a trailblazing epidemiologist who helped get cholera under control in Western Europe. It's a great story.
https://thelandofdesire.substack.com/...
March 12, 2020
"A zoonosis is an animal infection transmissible to humans. There are more such diseases than you might expect. AIDS is one. Influenza is a whole category of others. Pondering them as a group tends to reaffirm the old Darwinian truth (the darkest of his truths, well known and persistently forgotten) that humanity IS a kind of animal, inextricably connected with other animals; in origin and in descent, in sickness and in health." This is what David Quammen preaches in Spillover: Animal Infections and the Next Human Pandemic. Some have already given him credit for predicting the recent Ebola outbreak. If this sounds unappealing, it's my fault. Quammen is a researcher who writes with style and substance. He isn't the type who stays in his cubicle reviewing journals and online information. He is out in the field with his buddies and compatriots giving us a front line perspective on this serious issue.
To say this was an eye-opener for me probably understates its impact. I now think I know that every disease must have a reservoir. Smallpox basically resides in humans and is transmitted only among humans. Other diseases have either living or non-living reservoirs. Tetanus comes from a bacterium that resides in the soil. Cholera comes from a bacterium that resides in contaminated water. "A disease must have a portal of exit from the reservoir and a portal of entry into the host. This is how diseases are spread and new cases of infection occur. Examples of portals of exit are respiratory, the digestive tract, urinary, skin," etc. "Diseases can spread by three different, modes of transmission: contact transmission, vehicle transmission, and vector transmission." Let's remember the title of this book. Quammen is focused on "animal infections and the next human pandemic." A pandemic is an epidemic of infectious disease that has spread through human populations across a large region; for instance multiple continents, or even worldwide.
Quammen points out (and I am surprised as usual) that zoonosis isn't rare. In fact, "about 60 percent of all human infectious diseases currently known either cross routinely or have recently crossed between other animals and us...Ebola...bubonic plague...Spanish influenza...bovine tuberculosis, Lyme disease, West Nile fever...rabies, hanta virus pulmonary syndrome, antharx"...etc.
A lot of this book reads like a mystery. Some one or some thing has died unexpectedly and there is no immediate explanation for it. Quammen takes us along on these investigations. I came to like and respect this writer. He admires good science and points out with disdain efforts that fall short. His writing is intimate, filled with humor (often dark), and engaging.
"Most people aren't familiar with the word 'zoonotic,' but they have heard of SARS, they have heard of West Nile virus, they have heard of bird flu. They know someone who has suffered through Lyme disease and someone else who has died of AIDS. They have heard of Ebola, and they know that it's a very terrifying thing (though they may confuse it with E. coli, the bacterium that can kill you if you eat the wrong spinach). They are concerned. They are vaguely aware. But they don't have the time or the interest to consider a lot of scientific detail. I can say from experience that some people, if they hear you're writing a book about such things---about scary emerging diseases, about killer viruses, about pandemics---want you to cut to the chase. So they ask: 'Are we all gonna die?" I have made it my little policy to say yes."
Quammen is on the lookout for the "Next Big One." Some say his discussion of Ebola gives him a lot of "street cred." He states that few disagree that that Next Big One will be zoonotic. So it behooves us to understand what he is talking about. It's a longish book, but you can get a lot out of a little at a time.
I will leave you with a sample of how he passes on advice: " If your husband catches an ebola virus, give him food and water and love and maybe prayers but keep your distance, wait patiently, hope for the best — and, if he dies, don’t clean out his bowels by hand. Better to step back, blow a kiss and burn the hut.”
Given the reviews by my GR friends (including Greta, Max, carol, Jeanette, Hannah) and our current COVID-19 crisis, I thought a re-read would be beneficial. Was it ever! It was definitely worth reviewing zoonosis, pandemics, human behavior, and measures that can be taken. Quammen definitely deserves 5* ---and--- Do NOT Touch Your Face!
To say this was an eye-opener for me probably understates its impact. I now think I know that every disease must have a reservoir. Smallpox basically resides in humans and is transmitted only among humans. Other diseases have either living or non-living reservoirs. Tetanus comes from a bacterium that resides in the soil. Cholera comes from a bacterium that resides in contaminated water. "A disease must have a portal of exit from the reservoir and a portal of entry into the host. This is how diseases are spread and new cases of infection occur. Examples of portals of exit are respiratory, the digestive tract, urinary, skin," etc. "Diseases can spread by three different, modes of transmission: contact transmission, vehicle transmission, and vector transmission." Let's remember the title of this book. Quammen is focused on "animal infections and the next human pandemic." A pandemic is an epidemic of infectious disease that has spread through human populations across a large region; for instance multiple continents, or even worldwide.
Quammen points out (and I am surprised as usual) that zoonosis isn't rare. In fact, "about 60 percent of all human infectious diseases currently known either cross routinely or have recently crossed between other animals and us...Ebola...bubonic plague...Spanish influenza...bovine tuberculosis, Lyme disease, West Nile fever...rabies, hanta virus pulmonary syndrome, antharx"...etc.
A lot of this book reads like a mystery. Some one or some thing has died unexpectedly and there is no immediate explanation for it. Quammen takes us along on these investigations. I came to like and respect this writer. He admires good science and points out with disdain efforts that fall short. His writing is intimate, filled with humor (often dark), and engaging.
"Most people aren't familiar with the word 'zoonotic,' but they have heard of SARS, they have heard of West Nile virus, they have heard of bird flu. They know someone who has suffered through Lyme disease and someone else who has died of AIDS. They have heard of Ebola, and they know that it's a very terrifying thing (though they may confuse it with E. coli, the bacterium that can kill you if you eat the wrong spinach). They are concerned. They are vaguely aware. But they don't have the time or the interest to consider a lot of scientific detail. I can say from experience that some people, if they hear you're writing a book about such things---about scary emerging diseases, about killer viruses, about pandemics---want you to cut to the chase. So they ask: 'Are we all gonna die?" I have made it my little policy to say yes."
Quammen is on the lookout for the "Next Big One." Some say his discussion of Ebola gives him a lot of "street cred." He states that few disagree that that Next Big One will be zoonotic. So it behooves us to understand what he is talking about. It's a longish book, but you can get a lot out of a little at a time.
I will leave you with a sample of how he passes on advice: " If your husband catches an ebola virus, give him food and water and love and maybe prayers but keep your distance, wait patiently, hope for the best — and, if he dies, don’t clean out his bowels by hand. Better to step back, blow a kiss and burn the hut.”
Given the reviews by my GR friends (including Greta, Max, carol, Jeanette, Hannah) and our current COVID-19 crisis, I thought a re-read would be beneficial. Was it ever! It was definitely worth reviewing zoonosis, pandemics, human behavior, and measures that can be taken. Quammen definitely deserves 5* ---and--- Do NOT Touch Your Face!
March 17, 2020
Quamman explores zoonotic diseases, infectious diseases caused by pathogens that “spillover” from animals to man. The pathogen may be a virus, bacteria or parasite. Zoonotic diseases include well known ones like Ebola, Lyme disease, SARS, and AIDS, lesser known ones like Hendra virus, Marburg virus and Q fever, and ones just being recognized as zoonotic such as some forms of malaria. Zoonotic diseases require a reservoir animal, an animal that sustains the virus without serious complications. Reservoir animals feed a cycle of epidemics. The virus can be eliminated from all humans and still come back. Non-zoonotic infectious diseases like polio, smallpox and measles can be eradicated once the pathogen is eliminated from every human. Some non-zoonotic diseases may have originally jumped from an animal, for example measles from goats or sheep.
Zoonotic diseases may require a vector like a mosquito. A pathogen may jump from a bat or monkey to a human and then from human to human. Or it may jump to an intermediate animal that reproduces it in large quantities sufficient to infect humans. The reservoir animals for the Hendra virus are fruit bats, which pass it to horses, which are “amplifier” animals that pass it to humans. Fruit bats are suspected as the reservoir animal for Ebola. Gorillas and chimpanzees are susceptible to Ebola just like humans and many thousands have died from it. Outbreaks in humans have been caused by eating infected gorilla and chimpanzee meat.
It is important to consider the ecosystem of the animals and organisms involved in spreading infection. Lyme disease is a good example. Deer ticks infect humans and deer are often blamed as the reservoir but they are not. Adult ticks that feed off deer and humans fall off never to bite again. Both humans and deer are dead ends. They don’t spread the disease. Larval ticks feed off of small mammals such as shrews, chipmunks and particularly mice which are the reservoir animals for the Lyme disease bacterium. Larval ticks become infected from animals that have been bitten by infected nymphal ticks. To control the spread of the disease culling deer won’t work, the mice must be controlled, a near impossible task. The best way would be to encourage natural predators such as owls, foxes, weasels and the like. Unfortunately, woodlands today have been divided into ever smaller patches that don’t support these carnivores.
Zoonotic pathogens can be parasites, bacteria, DNA viruses or RNA viruses. RNA viruses like the flu, West Nile, Hendra, HIV and Ebola can quickly mutate turning into new infectious agents. Flu viruses are especially prone to reassortment, a process in which viruses of different subtypes exchange components creating new subtypes. Thus we regularly see new versions of the flu. Retroviruses like HIV are particularly sinister. HIV uses the invaded cell to turn its RNA into DNA which it inserts into the host cell’s DNA, producing more viruses and replicating every time the cell divides. There are a dozen variants of HIV in humans and each is believed to be the result of a separate spillover. Thus the Simian virus, SIV, spills over regularly to the human virus, HIV. While only the main variant of HIV is responsible for most deaths, a new dangerous one could cross over anytime. In contrast DNA viruses such as herpes viruses (only some zoonotic) self-correct errors in replication and have larger genomes. They cannot mutate so quickly and must be persistent in order to sustain themselves. A great example is the chickenpox virus (not zoonotic) that infects children causing an itchy rash. The virus remains after the rash is gone and ramps up late in life causing shingles. Transmission methods for viruses and other pathogens include airborne, oral-fecal (water and food contamination), blood-borne, sexual, vertical (mother to child), or the bite of an animal.
Modern animal husbandry densely packs large numbers of animals in close confinement. For example in the Netherlands dairy goats are housed in huge barns holding thousands of animals creating perfect conditions for the bacteria causing Q fever to grow. Q fever bacteria were spread everywhere when the infected manure was used to fertilize crops. When the fields dried out the wind picked up the loose soil. People downwind breathed in dust full of the highly contagious and lethal bacteria. SARS was spread in China from the markets that sold wild animals (some raised on farms) for food. The animals were crammed together and not cared for by the marketers. These conditions undermine their immune systems making it easier for the virus that had been held in check to spread. Another example is parrot fever carried particularly by parakeets and cockatoos that many breeders keep in close dirty confines allowing latent infections to erupt.
Statistical analysis can reveal the requirements for an epidemic. There must be a critical mass, a sufficient number of susceptible individuals in sufficient density. Then a virulent pathogen will quickly spread. But those who die and those who recover (now immune) are no longer susceptible. When the number and density of those susceptible falls too low the epidemic is over until the susceptible population is replenished, an endless cycle. Concentration and number of pathogens and their infection rate also have required parameters, different for each disease. A good analysis of these factors can predict which measures to control the outbreak will work and which won’t.
Quammen’s book consists largely of descriptions of outbreaks, each crafted as a detective story. People get sick, die and nobody understands it. Tenacious doctors, veterinarians and scientists come to investigate. Some work in labs identifying the pathogen. Others track the associations of the victims. Still others figure where to look for animal hosts, collect samples and get them to the labs. Quammen embellishes these stories with frightening descriptions of the disease spread and the victim’s plight. He details the many hurdles the investigators must overcome. Their aim is prevention. Too often there is little that can be done for the victims. After typically years of work and false leads they identify the reservoir animal and the means of transmission. It is a repetitive story and one doomed to repeat time and again.
As human population expands and encroaches on natural environments and as wild species adapt to human presence and expand into human habitat, we will see evermore spillover. The increasing number and density of both people and the animals they eat favor the spread of zoonotic diseases. Poor countries with limited resources are particularly prone to epidemics. Wherever disease breaks out, modern day frequent travel and extensive global supply chains can quickly spread it to distant locations. Quammen expresses particular concern about the flu virus given its ability to reassort potentially mixing highly infectious and lethal subtypes. But whether flu, HIV or something new we can be sure we will be facing many more epidemics. The good news is that modern science gives us many tools to contain these outbreaks. However, the current wave of science bashing, nationalism, politicizing and underfunding government agencies is troubling. We need the institutions defending us against communicable diseases such as the CDC and its counterparts to have the resources, science based direction and international cooperation that are essential to be vigilant and responsive.
Zoonotic diseases may require a vector like a mosquito. A pathogen may jump from a bat or monkey to a human and then from human to human. Or it may jump to an intermediate animal that reproduces it in large quantities sufficient to infect humans. The reservoir animals for the Hendra virus are fruit bats, which pass it to horses, which are “amplifier” animals that pass it to humans. Fruit bats are suspected as the reservoir animal for Ebola. Gorillas and chimpanzees are susceptible to Ebola just like humans and many thousands have died from it. Outbreaks in humans have been caused by eating infected gorilla and chimpanzee meat.
It is important to consider the ecosystem of the animals and organisms involved in spreading infection. Lyme disease is a good example. Deer ticks infect humans and deer are often blamed as the reservoir but they are not. Adult ticks that feed off deer and humans fall off never to bite again. Both humans and deer are dead ends. They don’t spread the disease. Larval ticks feed off of small mammals such as shrews, chipmunks and particularly mice which are the reservoir animals for the Lyme disease bacterium. Larval ticks become infected from animals that have been bitten by infected nymphal ticks. To control the spread of the disease culling deer won’t work, the mice must be controlled, a near impossible task. The best way would be to encourage natural predators such as owls, foxes, weasels and the like. Unfortunately, woodlands today have been divided into ever smaller patches that don’t support these carnivores.
Zoonotic pathogens can be parasites, bacteria, DNA viruses or RNA viruses. RNA viruses like the flu, West Nile, Hendra, HIV and Ebola can quickly mutate turning into new infectious agents. Flu viruses are especially prone to reassortment, a process in which viruses of different subtypes exchange components creating new subtypes. Thus we regularly see new versions of the flu. Retroviruses like HIV are particularly sinister. HIV uses the invaded cell to turn its RNA into DNA which it inserts into the host cell’s DNA, producing more viruses and replicating every time the cell divides. There are a dozen variants of HIV in humans and each is believed to be the result of a separate spillover. Thus the Simian virus, SIV, spills over regularly to the human virus, HIV. While only the main variant of HIV is responsible for most deaths, a new dangerous one could cross over anytime. In contrast DNA viruses such as herpes viruses (only some zoonotic) self-correct errors in replication and have larger genomes. They cannot mutate so quickly and must be persistent in order to sustain themselves. A great example is the chickenpox virus (not zoonotic) that infects children causing an itchy rash. The virus remains after the rash is gone and ramps up late in life causing shingles. Transmission methods for viruses and other pathogens include airborne, oral-fecal (water and food contamination), blood-borne, sexual, vertical (mother to child), or the bite of an animal.
Modern animal husbandry densely packs large numbers of animals in close confinement. For example in the Netherlands dairy goats are housed in huge barns holding thousands of animals creating perfect conditions for the bacteria causing Q fever to grow. Q fever bacteria were spread everywhere when the infected manure was used to fertilize crops. When the fields dried out the wind picked up the loose soil. People downwind breathed in dust full of the highly contagious and lethal bacteria. SARS was spread in China from the markets that sold wild animals (some raised on farms) for food. The animals were crammed together and not cared for by the marketers. These conditions undermine their immune systems making it easier for the virus that had been held in check to spread. Another example is parrot fever carried particularly by parakeets and cockatoos that many breeders keep in close dirty confines allowing latent infections to erupt.
Statistical analysis can reveal the requirements for an epidemic. There must be a critical mass, a sufficient number of susceptible individuals in sufficient density. Then a virulent pathogen will quickly spread. But those who die and those who recover (now immune) are no longer susceptible. When the number and density of those susceptible falls too low the epidemic is over until the susceptible population is replenished, an endless cycle. Concentration and number of pathogens and their infection rate also have required parameters, different for each disease. A good analysis of these factors can predict which measures to control the outbreak will work and which won’t.
Quammen’s book consists largely of descriptions of outbreaks, each crafted as a detective story. People get sick, die and nobody understands it. Tenacious doctors, veterinarians and scientists come to investigate. Some work in labs identifying the pathogen. Others track the associations of the victims. Still others figure where to look for animal hosts, collect samples and get them to the labs. Quammen embellishes these stories with frightening descriptions of the disease spread and the victim’s plight. He details the many hurdles the investigators must overcome. Their aim is prevention. Too often there is little that can be done for the victims. After typically years of work and false leads they identify the reservoir animal and the means of transmission. It is a repetitive story and one doomed to repeat time and again.
As human population expands and encroaches on natural environments and as wild species adapt to human presence and expand into human habitat, we will see evermore spillover. The increasing number and density of both people and the animals they eat favor the spread of zoonotic diseases. Poor countries with limited resources are particularly prone to epidemics. Wherever disease breaks out, modern day frequent travel and extensive global supply chains can quickly spread it to distant locations. Quammen expresses particular concern about the flu virus given its ability to reassort potentially mixing highly infectious and lethal subtypes. But whether flu, HIV or something new we can be sure we will be facing many more epidemics. The good news is that modern science gives us many tools to contain these outbreaks. However, the current wave of science bashing, nationalism, politicizing and underfunding government agencies is troubling. We need the institutions defending us against communicable diseases such as the CDC and its counterparts to have the resources, science based direction and international cooperation that are essential to be vigilant and responsive.
April 18, 2020
One does not need to be a science wiz to understand or enjoy this book.
Author David Quamman spills the beans on how disease spreads.
The original emergence of the virus ‘Hendra’, didn’t seem very dire or newsworthy unless you happened to live in eastern Australia.
In September 1994, a violent distress erupted among horses in a suburb at the north fringe of Brisbane.
The place itself is called Hendra.... a quiet neighborhood filled with
racecourses, racing people, weatherboard houses whose backyard had been converted to stables, newstands that sold tip sheets, corner café’s with names like ‘The Feed Bin’.
“The first victim was a bay mare named Drama Series, retired from racing and now heavily in foal—that is, pregnant and well along”.
“A zoonosis is an animal infection transmissible to humans”.
There was nothing dramatically wrong with Drama Series— but she had gotten sick. Her trainer was named Vic Rail...a shrewd and forcefully charming man.
Vic had a reputation for being ‘tough as nails’ in the local racing world.
Some people resented Vic Rail, but no one denied he knew horses.
Just before Drama Series died, ( temperature had been high, heart rate was high, there was facial swelling, and a frothy discharge from her nostrils), a veterinarian named Peter Reid didn’t perform a necropsy because Vic Rail couldn’t afford it and because nobody forced saw a disease emergency which every bit of data would’ve been crucial.
The cause of her death remained uncertain.
Then, 12 more animals died within the next several days, ( thrashing and gasping), “either expiring horrifically or euthanized”.
Reid later said....”the speed with which it went through those forces with unbelievable, but in these early moments no one had identified ‘it’”.
What was causing the mayhem? How was it spreading from one horse to another?
It was a very traumati time treating and trying to help the suffering animals with antibiotics, fluids, and anti-shock medicines.
Meanwhile, Vic Rail became sick. So had one of the other stable helpers. It seemed like they each had a touch of a bad flu.
Vic Rail died. An autopsy showed that his lungs were full of blood, other fluids, and
some sort of virus.
The other stable hand, named Ray Unwin, after a fever and flu symptoms, he recovered and survived.
As the horse deaths came to crescendo, the government of
Queensland had intervened, in the form of veterinarians and other personnel from the Department of Primary Industries (responsible for livestock, wildlife, and agriculture throughout the state).
The DPI veterinarians began doing necropsies.
They found the virus. It was something new -something never seen before but which
from its size and its shape, resembled members of a particular virus group: the paramyxoviruses.
Around the same time, researchers tested is sample tissue from Vic Rail’s kidney during his autopsy. That sample also yielded and identical virus from the horses — confirming that this equine morbillivirus didn’t afflict only equines.
The details and descriptions of how zoonotic pathogens afflict humans was written for mainstream every day people ( non scientists), to easily understand.
🦇🐴 🦜😊
“Nearly all zoonotic diseases result from infection by one of six kinds of pathogen: viruses, bacteria, fungi, protists, (a group of small complex creatures such as amoebae, formally misleadingly known as protozoans), prions, and worms”.
In time it was learned that
molecular tracks of Hendra virus had been exposed long before it struck Vic Rail’s horses.
Two years later after the Rail outbreak, a flying fox tested positive for antibodies, making it possible for the first isolation of Hendra virus from a bat.
The identification of flying foxes as reservoir hosts, plus the high levels of seroprevalence, caused public-image trouble for A group of animals that had a legacy of such trouble already.
Approval ratings for bats were never high- and with the new information in Australia they weren’t even lower.
There seem to be a lot of mystifying concerns around the bat-human relationship-There was much they didn’t know about the nature of the virus....
other than they knew it was very contagious, making livestock ill.
“An amplifier host is a creature in which a virus or other pathogen replicates— and from which it spews—with extraordinary abundance”.
“Spillover is the term used by disease ecologists (it has a different use for economists)
to denote the moment when pathogen passes from members of one species, as host, into members of another. It’s a focused event.
Hendra virus spilled over into Drama series ( from bats) and then into Vic Rail (from horses) in September 1994”.
Reading this book greatly helped me understand COV19, coronaviruses.... and how the viruses transfer from animals to humans.
This physical science and biology, where is easy to understand. Thank you, David Quamman!!
David has a funny bone too.
This book is as entertaining as it is informative.
Vegans: I applaud you!!
Thank you for your contributions to our planet.
This book didn’t scare me: it made me more aware!!!
I leave you with a song —-
(it kept ‘speaking/singing’ to me while reading this book).
By Sam Cooke: “What A Wonderful World”.
🎶 🎤 Sing along.....📀📣🎶
Request: if somebody knows how to insert the link to the song, “What a Wonderful Life”, by Sam Cooke, in a comment, I would appreciate it. 🎶... thanks!
Author David Quamman spills the beans on how disease spreads.
The original emergence of the virus ‘Hendra’, didn’t seem very dire or newsworthy unless you happened to live in eastern Australia.
In September 1994, a violent distress erupted among horses in a suburb at the north fringe of Brisbane.
The place itself is called Hendra.... a quiet neighborhood filled with
racecourses, racing people, weatherboard houses whose backyard had been converted to stables, newstands that sold tip sheets, corner café’s with names like ‘The Feed Bin’.
“The first victim was a bay mare named Drama Series, retired from racing and now heavily in foal—that is, pregnant and well along”.
“A zoonosis is an animal infection transmissible to humans”.
There was nothing dramatically wrong with Drama Series— but she had gotten sick. Her trainer was named Vic Rail...a shrewd and forcefully charming man.
Vic had a reputation for being ‘tough as nails’ in the local racing world.
Some people resented Vic Rail, but no one denied he knew horses.
Just before Drama Series died, ( temperature had been high, heart rate was high, there was facial swelling, and a frothy discharge from her nostrils), a veterinarian named Peter Reid didn’t perform a necropsy because Vic Rail couldn’t afford it and because nobody forced saw a disease emergency which every bit of data would’ve been crucial.
The cause of her death remained uncertain.
Then, 12 more animals died within the next several days, ( thrashing and gasping), “either expiring horrifically or euthanized”.
Reid later said....”the speed with which it went through those forces with unbelievable, but in these early moments no one had identified ‘it’”.
What was causing the mayhem? How was it spreading from one horse to another?
It was a very traumati time treating and trying to help the suffering animals with antibiotics, fluids, and anti-shock medicines.
Meanwhile, Vic Rail became sick. So had one of the other stable helpers. It seemed like they each had a touch of a bad flu.
Vic Rail died. An autopsy showed that his lungs were full of blood, other fluids, and
some sort of virus.
The other stable hand, named Ray Unwin, after a fever and flu symptoms, he recovered and survived.
As the horse deaths came to crescendo, the government of
Queensland had intervened, in the form of veterinarians and other personnel from the Department of Primary Industries (responsible for livestock, wildlife, and agriculture throughout the state).
The DPI veterinarians began doing necropsies.
They found the virus. It was something new -something never seen before but which
from its size and its shape, resembled members of a particular virus group: the paramyxoviruses.
Around the same time, researchers tested is sample tissue from Vic Rail’s kidney during his autopsy. That sample also yielded and identical virus from the horses — confirming that this equine morbillivirus didn’t afflict only equines.
The details and descriptions of how zoonotic pathogens afflict humans was written for mainstream every day people ( non scientists), to easily understand.
🦇🐴 🦜😊
“Nearly all zoonotic diseases result from infection by one of six kinds of pathogen: viruses, bacteria, fungi, protists, (a group of small complex creatures such as amoebae, formally misleadingly known as protozoans), prions, and worms”.
In time it was learned that
molecular tracks of Hendra virus had been exposed long before it struck Vic Rail’s horses.
Two years later after the Rail outbreak, a flying fox tested positive for antibodies, making it possible for the first isolation of Hendra virus from a bat.
The identification of flying foxes as reservoir hosts, plus the high levels of seroprevalence, caused public-image trouble for A group of animals that had a legacy of such trouble already.
Approval ratings for bats were never high- and with the new information in Australia they weren’t even lower.
There seem to be a lot of mystifying concerns around the bat-human relationship-There was much they didn’t know about the nature of the virus....
other than they knew it was very contagious, making livestock ill.
“An amplifier host is a creature in which a virus or other pathogen replicates— and from which it spews—with extraordinary abundance”.
“Spillover is the term used by disease ecologists (it has a different use for economists)
to denote the moment when pathogen passes from members of one species, as host, into members of another. It’s a focused event.
Hendra virus spilled over into Drama series ( from bats) and then into Vic Rail (from horses) in September 1994”.
Reading this book greatly helped me understand COV19, coronaviruses.... and how the viruses transfer from animals to humans.
This physical science and biology, where is easy to understand. Thank you, David Quamman!!
David has a funny bone too.
This book is as entertaining as it is informative.
Vegans: I applaud you!!
Thank you for your contributions to our planet.
This book didn’t scare me: it made me more aware!!!
I leave you with a song —-
(it kept ‘speaking/singing’ to me while reading this book).
By Sam Cooke: “What A Wonderful World”.
🎶 🎤 Sing along.....📀📣🎶
Request: if somebody knows how to insert the link to the song, “What a Wonderful Life”, by Sam Cooke, in a comment, I would appreciate it. 🎶... thanks!
February 28, 2020
Dr. Jan Pol is a practicing veterinarian in rural Michigan and the star of the National Geographic TV Series “The incredible Dr. Pol”.
He is also guilty of not meeting required minimum standards of veterinary care, and negligence. He doesn’t carry out surgery in a sterile environment, wear surgical gloves, a gown, a mask, and a cap during surgery.
I watched a few episodes and was appalled by what I saw, for instance during an assisted calving. He was probing with his bare arms in a cow’s birth canal, without gloves and without disinfecting either the cow or his arms. No disinfecting afterwards either; the farmer’s water well will do.
How in the world is this man getting away with this stuff, and become a TV star at that.
The next time there’s a virus outbreak in Michigan, scientists at least know where to look for patient zero and the superspreader alike.
(Review in progress)
He is also guilty of not meeting required minimum standards of veterinary care, and negligence. He doesn’t carry out surgery in a sterile environment, wear surgical gloves, a gown, a mask, and a cap during surgery.
I watched a few episodes and was appalled by what I saw, for instance during an assisted calving. He was probing with his bare arms in a cow’s birth canal, without gloves and without disinfecting either the cow or his arms. No disinfecting afterwards either; the farmer’s water well will do.
How in the world is this man getting away with this stuff, and become a TV star at that.
The next time there’s a virus outbreak in Michigan, scientists at least know where to look for patient zero and the superspreader alike.
(Review in progress)
July 18, 2020
"Ecco perché" (ho ripetuto come un mantra durante tutta la lettura.)
Non ne potevo più di sentir parlare di Covid. Quindi di leggere un tomo di più di 500 pagine non mi girava neanche per l'anticamera del cervello, anche se tutti i miei amici di libri me ne parlavano bene. Poi ho visto che Quammen ha scritto Perchè non eravamo pronti e a questo punto ho capito che dovevo leggere il primo.
Un libro che ha cominciato a inanellare premi fin dal 2012. Otto anni prima del maledetto Covid. Un libro sui virus. Su tutti i virus letali: Ebola, HIV, Sars, e un sacco di altri di cui abbiamo solo sentito la brezza sfiorarci le orecchie, tanto erano cose lontane, da noi non arrivano.
Temevo di annoiarmi o magari di spaventarmi, perchè ormai eravamo tutti esperti, non potendo più fare gli allenatori della Nazionale di Calcio, eravamo tutti diventati virologi, immunologi, tuttologi. Il panettiere sotto casa mi ha redarguita sui virus respiratori, perchè LUI sapeva benissimo che durante l'estate sarebbe scomparso (il Covid purtroppo, e non LUI!), mentre il mio compagno di coppia a Bigliardino, che abita vicino a Codogno, freme per ricominciare a giocare mentre io mi mantengo su una linea attendista: “forse è meglio aspettare, tanto ora fa troppo caldo”, alla faccia di tutti gli Zangrillo e i Burioni, e che qualcuno ce ne liberi per favore. Mia figlia mi diceva: “Leggere un tomo così sul Covid? Perchè vuoi farti del male?”
Invece ho fatto benissimo. Perchè mi sono divertita un sacco. Quammen ha scritto con un brio e la capacità di appassionare su argomenti che qualunque esperto avrebbe infarcito di dati inutili alla comprensione di chi virologo non è. Mi ha catturato con le storie sia degli scienziati di laboratorio e le loro scoperte e dei loro guai, ma soprattutto dei ricercatori dei virus nelle foreste, strani Indiana Jones che si infilano in grotte impestate di milioni di pipistrelli infetti, che traversano per tremila chilometri foreste raccogliendo cacche di animali nella ricerca di morbi contaminati, portandoti indietro nella storia per capire dove è avvenuto lo “Spillover”, e quando, e chi è l'animale ospite, l'originario, quello che non si ammala e lo porta dentro magari da chissà quanto, e se ce ne è un altro che amplifica il virus, ma che sta a contatto con gli umani, e che quindi facilita il salto, che so, un cavallo, un maiale, un'anatra.
E perchè per alcuni virus la battaglia è stata vinta (Poliomelite, Vaiolo) ma per altri potremo non farcela? Perchè quello dell'influenza cambia ogni anno? E perchè, santiddìo, ci sono nel mondo laboratori di ricerca sofisticatissimi (mutuati da quelli militari per la guerra batteriologica, ora politicamente scorretta) con livelli di sicurezza estrema, magari anche negli Stati Uniti, e questo cavolo di Covid ci ha preso alla sprovvista? Eppure tutti i ricercatori di alto livelli erano lì a dirsi “chissà quando arriverà il Big One”, la nuova pandemia, certi che ci sarebbe stata, ma senza dirci quando.
Non potevano dircelo: un sacco di cose sui virus, specie se nuovi, non si sanno. Non si sanno e basta. Si impara dopo. A parte il mio panettiere.
Se cinquecento e passa pagine sono troppe, basta venire a prendere il pane sotto casa mia, ma se volete avere le idee chiare affidatevi al libro di Quammen, vi assicuro che ne vale la pena, avvincente come un buon romanzo.
Le stelle potevano essere cinque e anche più, se nonché tutte le varianti delle scimmie dell'HIV mi hanno un po' assopito, e quindi ne ho tolto mezza, ma non di più.
Non ne potevo più di sentir parlare di Covid. Quindi di leggere un tomo di più di 500 pagine non mi girava neanche per l'anticamera del cervello, anche se tutti i miei amici di libri me ne parlavano bene. Poi ho visto che Quammen ha scritto Perchè non eravamo pronti e a questo punto ho capito che dovevo leggere il primo.
Un libro che ha cominciato a inanellare premi fin dal 2012. Otto anni prima del maledetto Covid. Un libro sui virus. Su tutti i virus letali: Ebola, HIV, Sars, e un sacco di altri di cui abbiamo solo sentito la brezza sfiorarci le orecchie, tanto erano cose lontane, da noi non arrivano.
Temevo di annoiarmi o magari di spaventarmi, perchè ormai eravamo tutti esperti, non potendo più fare gli allenatori della Nazionale di Calcio, eravamo tutti diventati virologi, immunologi, tuttologi. Il panettiere sotto casa mi ha redarguita sui virus respiratori, perchè LUI sapeva benissimo che durante l'estate sarebbe scomparso (il Covid purtroppo, e non LUI!), mentre il mio compagno di coppia a Bigliardino, che abita vicino a Codogno, freme per ricominciare a giocare mentre io mi mantengo su una linea attendista: “forse è meglio aspettare, tanto ora fa troppo caldo”, alla faccia di tutti gli Zangrillo e i Burioni, e che qualcuno ce ne liberi per favore. Mia figlia mi diceva: “Leggere un tomo così sul Covid? Perchè vuoi farti del male?”
Invece ho fatto benissimo. Perchè mi sono divertita un sacco. Quammen ha scritto con un brio e la capacità di appassionare su argomenti che qualunque esperto avrebbe infarcito di dati inutili alla comprensione di chi virologo non è. Mi ha catturato con le storie sia degli scienziati di laboratorio e le loro scoperte e dei loro guai, ma soprattutto dei ricercatori dei virus nelle foreste, strani Indiana Jones che si infilano in grotte impestate di milioni di pipistrelli infetti, che traversano per tremila chilometri foreste raccogliendo cacche di animali nella ricerca di morbi contaminati, portandoti indietro nella storia per capire dove è avvenuto lo “Spillover”, e quando, e chi è l'animale ospite, l'originario, quello che non si ammala e lo porta dentro magari da chissà quanto, e se ce ne è un altro che amplifica il virus, ma che sta a contatto con gli umani, e che quindi facilita il salto, che so, un cavallo, un maiale, un'anatra.
E perchè per alcuni virus la battaglia è stata vinta (Poliomelite, Vaiolo) ma per altri potremo non farcela? Perchè quello dell'influenza cambia ogni anno? E perchè, santiddìo, ci sono nel mondo laboratori di ricerca sofisticatissimi (mutuati da quelli militari per la guerra batteriologica, ora politicamente scorretta) con livelli di sicurezza estrema, magari anche negli Stati Uniti, e questo cavolo di Covid ci ha preso alla sprovvista? Eppure tutti i ricercatori di alto livelli erano lì a dirsi “chissà quando arriverà il Big One”, la nuova pandemia, certi che ci sarebbe stata, ma senza dirci quando.
Non potevano dircelo: un sacco di cose sui virus, specie se nuovi, non si sanno. Non si sanno e basta. Si impara dopo. A parte il mio panettiere.
Se cinquecento e passa pagine sono troppe, basta venire a prendere il pane sotto casa mia, ma se volete avere le idee chiare affidatevi al libro di Quammen, vi assicuro che ne vale la pena, avvincente come un buon romanzo.
Le stelle potevano essere cinque e anche più, se nonché tutte le varianti delle scimmie dell'HIV mi hanno un po' assopito, e quindi ne ho tolto mezza, ma non di più.
March 11, 2020
“Non dico tutto ciò allo scopo di angosciarvi o deprimervi. Non ho scritto questo libro per spaventare il pubblico, ma per renderlo più consapevole. Ecco cosa distingue gli esseri umani per esempio dai bruchi: noi, al contrario di loro, possiamo fare mosse intelligenti.”
Lo sapevate che quella che noi chiamiamo influenza e ogni inverno crediamo sia la stessa patologia, in realtà è causata da tre tipi di virus differenti?
E sapevate che da questi tre ceppi principali si diffondono ogni stagione molteplici forma virali?
Forse lo sapevate già ma pochi sanno quello che ormai è scientificamente provato, ossia che, quella che noi definiamo comune influenza, ha negli uccelli acquatici i più grandi serbatoi di questo tipo di virus.
Leggere questo voluminoso saggio mi ha fatto rendere conto realmente di quanta disinformazione ci sia riguardo alla virologia.
Così il debutto di questi anni ’20 ci ha catapultati in un mondo sconosciuto dove le giornate sono diventate un aggiornamento continuo sull’infezione mondiale in atto.
Il riconoscimento di una specificità virale è battezzato nei laboratori con il nome Covid-19 ma per la gente rimane Il Coronavirus come se fosse un virus unico e non una grande famiglia comprendente più virus che possono causare diverse infezioni, dal comune raffreddore a malattie più gravi come la sindrome respiratoria del Medio Oriente (MERS) e la sindrome respiratoria acuta grave (SARS).
Il giornalista scientifico David Quammen, collaboratore della prestigiosa rivista National Geographic, aveva forse una sfera magica quando nel 2012 scrisse in questo libro che un’epidemia potenzialmente pandemica si sarebbe presto verificata?
Solo una questione di tempo in cui l’incrocio di diversi elementi e le occasioni sfortunatamente propizie avrebbero causato la diffusione di un altro virus.
Senza essere realmente un preveggente, Quammen ha semplicemente fatto sue le deduzioni e teorie frutto di centinaia fra sperimentazioni in laboratorio e vere e proprie battute di caccia:
”Il Next Big One, la prossima grande epidemia, è un tema ricorrente tra gli epidemiologi di ogni parte del mondo. Ne ragionano, ne parlano e sono abituati a vedersi chiedere un parere in proposito. Mentre fanno esperimenti o studiano le pandemie del passato, il Big One ha sempre un posticino nei loro pensieri.”
Leggendo si scopre che, oltre ai Ghostbusters, esistono i Cacciatori di virus; personaggi che nella mia immaginazioni sfiorano le capacità dei supereroi:
sprezzanti di ogni pericolo tendono trappole a pericolosi pipistrelli serbatoio di virus primordiali e potenziali bombe chimiche sul pianeta terra;
oppure si cimentano in agguati a diversi tipi di scimmie anch’essi animali che conservano riserve infettive.
In nome della scienza una morìa di animali su cui dobbiamo chiudere un occhio forse due perché mi dicono che il fine giustifica i mezzi (???)
D’altro canto anche i virus, protagonisti di questa storia, sono riconosciuti come forme viventi e come tutte le forme viventi hanno questa cieca aspirazione a sopravvivere ad ogni costo.
Accade così che da dormienti, un bel (!!!) giorno, i Virus facciano un salto da una specie all’altra.
Questo significa il termine spillover
Come sempre in tutta questa storia c’entra anche l’attuale condizione del pianeta terra dove, diciamo, che l’Uomo ha smosso un po’ troppo gli equilibri preesistenti.
I virus riconoscono nell’uomo un ideale contenitore in cui moltiplicarsi e, grazie ai suoi spostamenti diffondersi
Il libro parte dal 1994 quando in Australia si diffuse un virus che fu chiamato Handra non fu certo il primo di una serie di nuovi e spaventosi patogeni, né il peggiore.”.
Quammen non segue una linea temporale ma viaggia attraverso i binari di un concetto fondamentale dove ”Le malattie animali e quelle umane sono, come vedremo, due fili strettamente intrecciati.”
Esiste un virus annidato in un ospite serbatoio, esiste un ospite di amplificazione e la vittima potenziale
Ma non è solo una questione di caso quanto una storia dell’uomo che converge verso un’amplificazione di questo fenomeno che va analizzato secondo tre elementi di riflessione:
1. Devastazione ambientale che va dalla deforestazione alla trasformazione degli ambienti e il loro sfruttamento;
la caccia agli animali selvatici (”(strano, quando lo fanno gli africani è «bracconaggio », quando lo fanno gli occidentali è uno « sport »!!!!!!);
inquinamento; esaurimento delle risorse.
2. Il riconoscimento da parte degli esperti di un universo di viventi come virus, batteri, funghi, protisti e altri organismi, molti dei quali parassiti. Una dimensione che è stata nominata «virosfera»
3. Le conseguenze di una massiccia deforestazione risvegliano molti agenti patogeni che sfrattati dal loro habitat possono o estinguersi o trovare una nuova casa e, in questo caso, le occasioni favorevoli sono moltiplicate dal numero considerevole di esseri umani sul pianeta Terra.
Appassiona questa lettura che ci porta a conoscenza anche di patologie che credevano di conoscere. Ad esempio le origini dell’AIDS che pensavamo di collocare negli USA degli anni ’80 ed invece sono in Africa e, addirittura, nel 1908 (!!!).
Un libro che ci spiega concetti prima sconosciuti dalla zoonosi allo spillover che titola l’opera
” Lo spillover è un concetto diverso dall’emergenza, a cui è comunque collegato. Nell’uso corrente in ecologia ed epidemiologia (viene utilizzato anche dagli economisti, con un altro significato), lo spillover (che potremmo tradurre con « tracimazione ») indica il momento in cui un patogeno passa da una specie ospite a un’altra. “
Lettrici e lettori: leggete questo libro.
Essere informati ci dà modo di parlarne a chi letture non ne fa.
Diffondere conoscenze scientifiche su ciò che sta accadendo è importante perché coscienza, responsabilità ed equilibrio siano alla portata di tutti.
In questi giorni oltre ai comportamenti spropositati da chi preso dal panico non guarda in faccia a nessuno, se ne affiancano altri che, al contrario, negano i rischi.
Ho sentito addirittura dire che il virus è stato mandato da Trump per annientare la Cina...
Non dico altro..
”Quindi prima di reagire in modo calmo o isterico, con intelligenza o stupidamente, dovremmo conoscere almeno le basi teoriche e le dinamiche di quel che è in gioco. Dovremmo sapere che le recenti epidemie di nuove zoonosi, oltre alla riproposizione e alla diffusione di altre già viste, fanno parte di un quadro generale più vasto, creato dal genere umano. Dovremmo renderci conto che sono conseguenze di nostre azioni, non accidenti che ci capitano tra capo e collo. Dovremmo capire che alcune situazioni da noi generate sembrano praticamente inevitabili, ma altre sono ancora controllabili.”
Lo sapevate che quella che noi chiamiamo influenza e ogni inverno crediamo sia la stessa patologia, in realtà è causata da tre tipi di virus differenti?
E sapevate che da questi tre ceppi principali si diffondono ogni stagione molteplici forma virali?
Forse lo sapevate già ma pochi sanno quello che ormai è scientificamente provato, ossia che, quella che noi definiamo comune influenza, ha negli uccelli acquatici i più grandi serbatoi di questo tipo di virus.
Leggere questo voluminoso saggio mi ha fatto rendere conto realmente di quanta disinformazione ci sia riguardo alla virologia.
Così il debutto di questi anni ’20 ci ha catapultati in un mondo sconosciuto dove le giornate sono diventate un aggiornamento continuo sull’infezione mondiale in atto.
Il riconoscimento di una specificità virale è battezzato nei laboratori con il nome Covid-19 ma per la gente rimane Il Coronavirus come se fosse un virus unico e non una grande famiglia comprendente più virus che possono causare diverse infezioni, dal comune raffreddore a malattie più gravi come la sindrome respiratoria del Medio Oriente (MERS) e la sindrome respiratoria acuta grave (SARS).
Il giornalista scientifico David Quammen, collaboratore della prestigiosa rivista National Geographic, aveva forse una sfera magica quando nel 2012 scrisse in questo libro che un’epidemia potenzialmente pandemica si sarebbe presto verificata?
Solo una questione di tempo in cui l’incrocio di diversi elementi e le occasioni sfortunatamente propizie avrebbero causato la diffusione di un altro virus.
Senza essere realmente un preveggente, Quammen ha semplicemente fatto sue le deduzioni e teorie frutto di centinaia fra sperimentazioni in laboratorio e vere e proprie battute di caccia:
”Il Next Big One, la prossima grande epidemia, è un tema ricorrente tra gli epidemiologi di ogni parte del mondo. Ne ragionano, ne parlano e sono abituati a vedersi chiedere un parere in proposito. Mentre fanno esperimenti o studiano le pandemie del passato, il Big One ha sempre un posticino nei loro pensieri.”
Leggendo si scopre che, oltre ai Ghostbusters, esistono i Cacciatori di virus; personaggi che nella mia immaginazioni sfiorano le capacità dei supereroi:
sprezzanti di ogni pericolo tendono trappole a pericolosi pipistrelli serbatoio di virus primordiali e potenziali bombe chimiche sul pianeta terra;
oppure si cimentano in agguati a diversi tipi di scimmie anch’essi animali che conservano riserve infettive.
In nome della scienza una morìa di animali su cui dobbiamo chiudere un occhio forse due perché mi dicono che il fine giustifica i mezzi (???)
D’altro canto anche i virus, protagonisti di questa storia, sono riconosciuti come forme viventi e come tutte le forme viventi hanno questa cieca aspirazione a sopravvivere ad ogni costo.
Accade così che da dormienti, un bel (!!!) giorno, i Virus facciano un salto da una specie all’altra.
Questo significa il termine spillover
Come sempre in tutta questa storia c’entra anche l’attuale condizione del pianeta terra dove, diciamo, che l’Uomo ha smosso un po’ troppo gli equilibri preesistenti.
I virus riconoscono nell’uomo un ideale contenitore in cui moltiplicarsi e, grazie ai suoi spostamenti diffondersi
Il libro parte dal 1994 quando in Australia si diffuse un virus che fu chiamato Handra non fu certo il primo di una serie di nuovi e spaventosi patogeni, né il peggiore.”.
Quammen non segue una linea temporale ma viaggia attraverso i binari di un concetto fondamentale dove ”Le malattie animali e quelle umane sono, come vedremo, due fili strettamente intrecciati.”
Esiste un virus annidato in un ospite serbatoio, esiste un ospite di amplificazione e la vittima potenziale
Ma non è solo una questione di caso quanto una storia dell’uomo che converge verso un’amplificazione di questo fenomeno che va analizzato secondo tre elementi di riflessione:
1. Devastazione ambientale che va dalla deforestazione alla trasformazione degli ambienti e il loro sfruttamento;
la caccia agli animali selvatici (”(strano, quando lo fanno gli africani è «bracconaggio », quando lo fanno gli occidentali è uno « sport »!!!!!!);
inquinamento; esaurimento delle risorse.
2. Il riconoscimento da parte degli esperti di un universo di viventi come virus, batteri, funghi, protisti e altri organismi, molti dei quali parassiti. Una dimensione che è stata nominata «virosfera»
3. Le conseguenze di una massiccia deforestazione risvegliano molti agenti patogeni che sfrattati dal loro habitat possono o estinguersi o trovare una nuova casa e, in questo caso, le occasioni favorevoli sono moltiplicate dal numero considerevole di esseri umani sul pianeta Terra.
Appassiona questa lettura che ci porta a conoscenza anche di patologie che credevano di conoscere. Ad esempio le origini dell’AIDS che pensavamo di collocare negli USA degli anni ’80 ed invece sono in Africa e, addirittura, nel 1908 (!!!).
Un libro che ci spiega concetti prima sconosciuti dalla zoonosi allo spillover che titola l’opera
” Lo spillover è un concetto diverso dall’emergenza, a cui è comunque collegato. Nell’uso corrente in ecologia ed epidemiologia (viene utilizzato anche dagli economisti, con un altro significato), lo spillover (che potremmo tradurre con « tracimazione ») indica il momento in cui un patogeno passa da una specie ospite a un’altra. “
Lettrici e lettori: leggete questo libro.
Essere informati ci dà modo di parlarne a chi letture non ne fa.
Diffondere conoscenze scientifiche su ciò che sta accadendo è importante perché coscienza, responsabilità ed equilibrio siano alla portata di tutti.
In questi giorni oltre ai comportamenti spropositati da chi preso dal panico non guarda in faccia a nessuno, se ne affiancano altri che, al contrario, negano i rischi.
Ho sentito addirittura dire che il virus è stato mandato da Trump per annientare la Cina...
Non dico altro..
”Quindi prima di reagire in modo calmo o isterico, con intelligenza o stupidamente, dovremmo conoscere almeno le basi teoriche e le dinamiche di quel che è in gioco. Dovremmo sapere che le recenti epidemie di nuove zoonosi, oltre alla riproposizione e alla diffusione di altre già viste, fanno parte di un quadro generale più vasto, creato dal genere umano. Dovremmo renderci conto che sono conseguenze di nostre azioni, non accidenti che ci capitano tra capo e collo. Dovremmo capire che alcune situazioni da noi generate sembrano praticamente inevitabili, ma altre sono ancora controllabili.”
July 6, 2021
I find solace in knowledge.
In research.
In science.
In realizing (again) that history is a teacher.
Reading a book about pandemics during a pandemic might not work for everyone, but I find comfort in realizing that shit has happened many many times before and it will happen again and again.
I like to remember that we, as humans, are animals, and no matter what we do, we are not infallible.
Our own hubris is and always will be our biggest downfall.
I like to remember that science and research can save lives and change history.
I read David Quammen's SPILLOVER: Animal Infections and the Next Human Pandemic, a 500+ page book in a few short days because:
1) It is great writing and hard to put down
2) I've got the time as work is a slow trickle now (early weeks of the Covid pandemic in Spring 2020)
3) I craved those reminders, stated above.
Quammen is a first-rate researcher and writer, the book details the emergence and spillover of zoonotic diseases that cross from non-human animals to human animals, many I've heard of, and some I hadn't.
The book opens with a detailed history or the Hendra virus, which attacks both horses and humans that was first studied in Australia in the 90s. Through forensics, and many many samples, this virus, and many other recent viruses have been traced to various species of bats (SARS, Marburg, Ebola, and now COVID-19).
Quammen and some bat biologists speculate why these mammals, an ancient and highly diversified group, are the reservoir host for so many viruses. These chapters were amongst my favorite in the book - highly informative and highly readable.
Written in 2012, but pertinent in this very moment, and will continue to be.
In research.
In science.
In realizing (again) that history is a teacher.
Reading a book about pandemics during a pandemic might not work for everyone, but I find comfort in realizing that shit has happened many many times before and it will happen again and again.
I like to remember that we, as humans, are animals, and no matter what we do, we are not infallible.
Our own hubris is and always will be our biggest downfall.
I like to remember that science and research can save lives and change history.
I read David Quammen's SPILLOVER: Animal Infections and the Next Human Pandemic, a 500+ page book in a few short days because:
1) It is great writing and hard to put down
2) I've got the time as work is a slow trickle now (early weeks of the Covid pandemic in Spring 2020)
3) I craved those reminders, stated above.
Quammen is a first-rate researcher and writer, the book details the emergence and spillover of zoonotic diseases that cross from non-human animals to human animals, many I've heard of, and some I hadn't.
The book opens with a detailed history or the Hendra virus, which attacks both horses and humans that was first studied in Australia in the 90s. Through forensics, and many many samples, this virus, and many other recent viruses have been traced to various species of bats (SARS, Marburg, Ebola, and now COVID-19).
Quammen and some bat biologists speculate why these mammals, an ancient and highly diversified group, are the reservoir host for so many viruses. These chapters were amongst my favorite in the book - highly informative and highly readable.
Written in 2012, but pertinent in this very moment, and will continue to be.
November 28, 2012
Full disclosure first, I'm a fan of this type of non-fiction. Laurie Garret - The Coming Plague, Richard Preston - The Hot Zone, Randy Shilts - And the Band Played On... the list goes on and on. I love this stuff. But having said that, this is truly the best thing I've ever read on the subject of infectious agents spilling over from their host species into humans. Brilliant, readable and absolutely spell-binding, Quammen's description of mutation, illness and the effect of human encroachment into different environments turns science into art. Without a doubt this guy knows his stuff and how to write about it. Highly recommended!
August 27, 2014
Disclamer: I received this book from the Goodreads First Reads Giveaway program.
I'm very grateful that I did. I happen to be a physician, specializing in Public Health and Preventive Medicine. I work in an environment where epidemiology underlies everything I do. Therefore, I feel that I can give an especially educated evaluation of this book.
The first thing I would like to comment on is the cover. It's an eye-catching blurred photograph of a screaming mandrill. Everywhere I carried the book (which is everywhere at work; I could not put it down) people looked at it and asked me what I was reading. Beautiful and suitable, the artwork sets the stage for the gripping narratives contained within.
This is a book written for the intellectually curious. Quammen, as a journalist, understands that some of the material covered in this book can be esoteric for those not trained in the subject. He explains complex subjects clearly, and this is the important part, does not condescend or dumb it down. This makes the content accessible to everyone who may be interested, and the material is fascinating.
As a public health physician, I thought I was fairly well-informed on the subject of zoonoses. I was delighted to find that this book is chock full of new, up-to-date information, and I had never even heard of some of the diseases he discussed. For example, I had though the reservoir for SARS was the civet cat. I had no idea that it was...well, you have to read the book. This book is as gripping and suspenseful as any thriller or mystery, and more terrifying, to boot, since this is non-fiction. As I am typing this, Hanta virus is affecting visitors to Yosemite National Park, Ebola is breaking out in Uganda and The Congo, and who knows what other mystery illnesses have yet to be identified and are lurking for the opportunity to breakout into the greater population.
David Quammen has a delightfully sardonic sense of humor, and as he spins his tales, backed with a tremendous amount of field work on his part, one feels as if they are right there in the field with him and the researchers collecting bat piss (yes, really) or strolling the Hong Kong markets, or munching on Bamboo Rat hot-pot (apparently mild and sweet, quite tasty).
I found myself reading the book like a good, no, excellent, novel. Normally with non-fiction, I pick it up and put it down in spurts. This book is so engrossing, though, that I found myself even walking down the street from the train station to work while reading this (a substantial hardcover, mind you). Quite a few of my co-workers want to read it, particularly the epidemiologists and physicians, but please don't hold back if you haven't got the background. This book is written so as to be accessible to anyone who has the interest. Everyone should be interested. The next big outbreak is inevitable because of human manipulation of climate, habitat and overcrowded conditions and intrusions into the wild, bringing us more and more in contact with potential pathogens. This book is a sobering look at the changing conditions in the world and how they leave us very, very vulnerable. This is easily the most frightening book I have read in a long, long time. Thank you, David for the work of love that produced this.
Note for Goodreads: the page count is wrong; please correct it. The correct page number is 520 pages of text, plus a long reference section.
I'm very grateful that I did. I happen to be a physician, specializing in Public Health and Preventive Medicine. I work in an environment where epidemiology underlies everything I do. Therefore, I feel that I can give an especially educated evaluation of this book.
The first thing I would like to comment on is the cover. It's an eye-catching blurred photograph of a screaming mandrill. Everywhere I carried the book (which is everywhere at work; I could not put it down) people looked at it and asked me what I was reading. Beautiful and suitable, the artwork sets the stage for the gripping narratives contained within.
This is a book written for the intellectually curious. Quammen, as a journalist, understands that some of the material covered in this book can be esoteric for those not trained in the subject. He explains complex subjects clearly, and this is the important part, does not condescend or dumb it down. This makes the content accessible to everyone who may be interested, and the material is fascinating.
As a public health physician, I thought I was fairly well-informed on the subject of zoonoses. I was delighted to find that this book is chock full of new, up-to-date information, and I had never even heard of some of the diseases he discussed. For example, I had though the reservoir for SARS was the civet cat. I had no idea that it was...well, you have to read the book. This book is as gripping and suspenseful as any thriller or mystery, and more terrifying, to boot, since this is non-fiction. As I am typing this, Hanta virus is affecting visitors to Yosemite National Park, Ebola is breaking out in Uganda and The Congo, and who knows what other mystery illnesses have yet to be identified and are lurking for the opportunity to breakout into the greater population.
David Quammen has a delightfully sardonic sense of humor, and as he spins his tales, backed with a tremendous amount of field work on his part, one feels as if they are right there in the field with him and the researchers collecting bat piss (yes, really) or strolling the Hong Kong markets, or munching on Bamboo Rat hot-pot (apparently mild and sweet, quite tasty).
I found myself reading the book like a good, no, excellent, novel. Normally with non-fiction, I pick it up and put it down in spurts. This book is so engrossing, though, that I found myself even walking down the street from the train station to work while reading this (a substantial hardcover, mind you). Quite a few of my co-workers want to read it, particularly the epidemiologists and physicians, but please don't hold back if you haven't got the background. This book is written so as to be accessible to anyone who has the interest. Everyone should be interested. The next big outbreak is inevitable because of human manipulation of climate, habitat and overcrowded conditions and intrusions into the wild, bringing us more and more in contact with potential pathogens. This book is a sobering look at the changing conditions in the world and how they leave us very, very vulnerable. This is easily the most frightening book I have read in a long, long time. Thank you, David for the work of love that produced this.
Note for Goodreads: the page count is wrong; please correct it. The correct page number is 520 pages of text, plus a long reference section.
March 23, 2020
Spillover: salto di specie!
Sinceramente non ne avevo mai sentito parlare prima, non posso negare la mia ignoranza sull'argomento. Sapevo delle iterazioni tra specie viventi, come non potrebbe?
Così, data la situazione attuale catastrofica, che stiamo vivendo, prenoto subito il libro in biblioteca e per un'insperata fortuna riesco ad averlo, data la chiusura di tutte le scuole e biblioteche, per decreto.
Appena ho il libro in mano, una scossa lungo la schiena mi pervade, il volume è molto poderoso, son 600 pagine di saggio, sto facendo la cosa giusta? Devo!
Sì, devo, anzi dovremmo tutti leggerlo, perchè racchiude un'ampia gamma di informazioni fondamentali, non solo per la pandemia in atto.
Il libro è una cronistoria delle zoonosi, cioè quelle malattie che passano da esseri animali ad esseri umani.
Così Quammen ci porta alle origini di esse, almeno alle origini degli studi su di esse (le zoonosi). Il testo è prettamente di divulgazione scientifica, ma scritto sotto forma di racconto di viaggio. Il viaggio è multiforme, ci sono vari patogeni in natura, perchè molti di questi ci colpiscono e colpiscono altri esseri viventi, alle volte in molto assai virulento e letale?
La risposta, anzi, le risposte sono molteplici e sono, per la maggior parte, da ricercare nel nostro Impatto sull'ecosistema Terra. L'evoluzione non è prerogativa degli esseri umani, qualsiasi essere vivente si evolve, fa parte della vita stessa. Ma quando si modificano gli equilibri costruiti nel corso di migliaia se non milioni di anni, in poco tempo, poi le conseguenze sono disastrose. Noi esseri umani abbiamo e continuiamo a depredare la Terra, deforestando interi spazi che negli anni avevano sviluppato un loro ecosistema, noi lo facciamo fuori nel giro di pochi giorni, stiamo e abbiamo fatto estinguere non so quante specie animali e vegetali negli ultimi decenni e non ce ne accorgiamo, magari leggiamo la notizia di una estinzione, così, ma... Però ora il coronavirus ci fa paura, forse abbiamo bisogno di una "bomba" sotto il c... per risvegliarci?
Sinceramente non ne avevo mai sentito parlare prima, non posso negare la mia ignoranza sull'argomento. Sapevo delle iterazioni tra specie viventi, come non potrebbe?
Così, data la situazione attuale catastrofica, che stiamo vivendo, prenoto subito il libro in biblioteca e per un'insperata fortuna riesco ad averlo, data la chiusura di tutte le scuole e biblioteche, per decreto.
Appena ho il libro in mano, una scossa lungo la schiena mi pervade, il volume è molto poderoso, son 600 pagine di saggio, sto facendo la cosa giusta? Devo!
Sì, devo, anzi dovremmo tutti leggerlo, perchè racchiude un'ampia gamma di informazioni fondamentali, non solo per la pandemia in atto.
Il libro è una cronistoria delle zoonosi, cioè quelle malattie che passano da esseri animali ad esseri umani.
Così Quammen ci porta alle origini di esse, almeno alle origini degli studi su di esse (le zoonosi). Il testo è prettamente di divulgazione scientifica, ma scritto sotto forma di racconto di viaggio. Il viaggio è multiforme, ci sono vari patogeni in natura, perchè molti di questi ci colpiscono e colpiscono altri esseri viventi, alle volte in molto assai virulento e letale?
La risposta, anzi, le risposte sono molteplici e sono, per la maggior parte, da ricercare nel nostro Impatto sull'ecosistema Terra. L'evoluzione non è prerogativa degli esseri umani, qualsiasi essere vivente si evolve, fa parte della vita stessa. Ma quando si modificano gli equilibri costruiti nel corso di migliaia se non milioni di anni, in poco tempo, poi le conseguenze sono disastrose. Noi esseri umani abbiamo e continuiamo a depredare la Terra, deforestando interi spazi che negli anni avevano sviluppato un loro ecosistema, noi lo facciamo fuori nel giro di pochi giorni, stiamo e abbiamo fatto estinguere non so quante specie animali e vegetali negli ultimi decenni e non ce ne accorgiamo, magari leggiamo la notizia di una estinzione, così, ma... Però ora il coronavirus ci fa paura, forse abbiamo bisogno di una "bomba" sotto il c... per risvegliarci?
September 28, 2013
A "spillover" occurs when a microbe crosses over from an animal to humans, as an infectious disease. David Quammen describes many examples of this: SARS, ebola, HIV, influenza, marburg and hendra.
Each chapter is a detective story--scientists, veterinarians and medical researchers are detectives searching for the source of a disease. The source is usually a reservoir--an animal that carries the microbe, but is not usually harmed by the microbe.
And--now here's the best part--Quammen is not a stay-at-home researcher. He visits the scientists and interviews them over extended periods of time. And better yet--he accompanies scientists on research expeditions all over the world, in search of the reservoirs for terrible diseases. Quammen describes, in detail, what it is like to hunt for elusive viruses in bats, chimpanzees, monkeys, and horses. Often, the researchers must take special precautions to avoid being infected themselves. Sometimes these precautions fail, with awful consequences.
Quammen investigates why spillovers occur when and where they do. It's a combination of ecology and evolution. A microbe is carried by an animal reservoir, and usually in equilibrium where the animal is unharmed. Then, some dramatic change to the environment occurs, usually it is caused by humans impinging on the local ecology. The microbe mutates and jumps either to a vector (like a mosquito or a rat) or directly to a human. Further mutations then allow the microbe to jump from one human to another, causing an epidemic.
Researchers agree that in the future, there will be lethal epidemics like AIDS and the influenza pandemic of 1918. Such epidemics are totally unpredictable, because of the diversity of human behavior.
David Quammen is an excellent writer--he has a wonderful style. It is obvious from his enthusiasm and from his extensive travels, that this book represents his life-long efforts. Spillover is a sequence of detective mysteries and adventure stories, all rolled up into one. I highly recommend it!
Each chapter is a detective story--scientists, veterinarians and medical researchers are detectives searching for the source of a disease. The source is usually a reservoir--an animal that carries the microbe, but is not usually harmed by the microbe.
And--now here's the best part--Quammen is not a stay-at-home researcher. He visits the scientists and interviews them over extended periods of time. And better yet--he accompanies scientists on research expeditions all over the world, in search of the reservoirs for terrible diseases. Quammen describes, in detail, what it is like to hunt for elusive viruses in bats, chimpanzees, monkeys, and horses. Often, the researchers must take special precautions to avoid being infected themselves. Sometimes these precautions fail, with awful consequences.
Quammen investigates why spillovers occur when and where they do. It's a combination of ecology and evolution. A microbe is carried by an animal reservoir, and usually in equilibrium where the animal is unharmed. Then, some dramatic change to the environment occurs, usually it is caused by humans impinging on the local ecology. The microbe mutates and jumps either to a vector (like a mosquito or a rat) or directly to a human. Further mutations then allow the microbe to jump from one human to another, causing an epidemic.
Researchers agree that in the future, there will be lethal epidemics like AIDS and the influenza pandemic of 1918. Such epidemics are totally unpredictable, because of the diversity of human behavior.
David Quammen is an excellent writer--he has a wonderful style. It is obvious from his enthusiasm and from his extensive travels, that this book represents his life-long efforts. Spillover is a sequence of detective mysteries and adventure stories, all rolled up into one. I highly recommend it!
January 8, 2013
This book was an exciting and informative tour of zoonotic diseases, but the fragmented style diminished my enjoyment. Quammen practices an annoying form of gonzo journalism in which he needlessly inserts himself into the narrative because he is too lazy to do otherwise.
There are numerous throwaway chapters that are included for no other reason than because Quammen made a trip or did the interview. For instance, many pages are devoted to the unenlightening tale of a scientist who accidentally pricks herself with an Ebola-carrying needle. We learn of this woman's childhood, educational background, family life, the cleanliness of her home, etc. We learn of the boredom of her long quarantine and how she and her friends shared unfunny jokes via email about how her quarantine diet is high calorie. One may think that Quammen is building up to some sort of cliffhanger in which this poor woman ends up showing Ebola symptoms, but it is clear from the start (as he describes his visit to her house and the interview) that this didn't happen. This whole ordeal could have been omitted or replaced with one sentence, but Quammen must feel that every interview he conducts deserves many pages of text. (After a few minutes of reflection, I now realize the author's intent with this Ebola-quarantine section. He is de-sensationalizing Ebola by telling a tale of potential laboratory-borne infection completely lacking any excitement or exploding bodies, in stark contrast to THE HOT ZONE.)
While these aren't direct quotes, the book is strewn with needless editorializing along the lines of "I think the guy who first discovered the cause of malaria is one cool dude," and there are way too many one word sentences like "Boring" or "Neato." Seriously.
Worst of all, near the end of the book Quammen takes a novelistic turn and tells an entirely fictional account of a patient zero carrying AIDS from the jungle of central Africa into the city. While this perhaps is demonstrating a plausible scenario for the first cases of human to human transmission of the virus, the level of trivial detail is infuriating. Should we applaud Quammen for so humanizing his fictional character and eagerly await the publication of his first novel? Or should we be upset that so many pages of a 700 page book are wasted on an Introduction-to-Creative-Writing-quality novella?
Nonetheless, most of the book is enthralling. But I dread the approaching day in which all journalistic nonfiction will be told in this short-attention-span, MTV-News-inspired format.
There are numerous throwaway chapters that are included for no other reason than because Quammen made a trip or did the interview. For instance, many pages are devoted to the unenlightening tale of a scientist who accidentally pricks herself with an Ebola-carrying needle. We learn of this woman's childhood, educational background, family life, the cleanliness of her home, etc. We learn of the boredom of her long quarantine and how she and her friends shared unfunny jokes via email about how her quarantine diet is high calorie. One may think that Quammen is building up to some sort of cliffhanger in which this poor woman ends up showing Ebola symptoms, but it is clear from the start (as he describes his visit to her house and the interview) that this didn't happen. This whole ordeal could have been omitted or replaced with one sentence, but Quammen must feel that every interview he conducts deserves many pages of text. (After a few minutes of reflection, I now realize the author's intent with this Ebola-quarantine section. He is de-sensationalizing Ebola by telling a tale of potential laboratory-borne infection completely lacking any excitement or exploding bodies, in stark contrast to THE HOT ZONE.)
While these aren't direct quotes, the book is strewn with needless editorializing along the lines of "I think the guy who first discovered the cause of malaria is one cool dude," and there are way too many one word sentences like "Boring" or "Neato." Seriously.
Worst of all, near the end of the book Quammen takes a novelistic turn and tells an entirely fictional account of a patient zero carrying AIDS from the jungle of central Africa into the city. While this perhaps is demonstrating a plausible scenario for the first cases of human to human transmission of the virus, the level of trivial detail is infuriating. Should we applaud Quammen for so humanizing his fictional character and eagerly await the publication of his first novel? Or should we be upset that so many pages of a 700 page book are wasted on an Introduction-to-Creative-Writing-quality novella?
Nonetheless, most of the book is enthralling. But I dread the approaching day in which all journalistic nonfiction will be told in this short-attention-span, MTV-News-inspired format.
June 6, 2020
Might be beating a dead horse—or preferably not, considering the horse-borne Hendra virus that kickstarts this book—to sing my praises now for Quammen’s masterwork. An investigation into zoonoses (i.e., animals’ diseases that jump into humans), hitting all the big names from bloody Ebola to body-ravaging HIV and AIDS, Spillover also prioritises the narrative impulse over the encyclopedic, laying down each disease’s fascinating story but moreover tying them all together into a larger and frankly terrifying picture of what might await us as we encroach on more of the natural world and then encounter the wrong bat; and makes it all so damn readable as a result. Little surprise there as Quammen, who makes no secret his love for Faulkner, is conscious of and clearly here practices good writing. Particularly choice bit: when Quammen, though respectful ("I don’t like criticizing a colleague"), nevertheless low-key savages The Hot Zone for exaggerating Ebola’s symptoms to great if altogether disingenuous effect. Spillover is necessarily infused towards the end with a heavy note of uncertainty, so long as the Next Big (Final?) One remains still at large. But Quammen everywhere writes driven by a strong sense of certainty and, with his impressive fieldwork, awesome authority.
April 5, 2020
Attraverso i ponti
David Quammen si occupa di divulgazione scientifica e biologia evolutiva. In questo libro racconta cosa siano i virus, se siano da considerare esseri viventi oppure no, e come si sviluppi la loro esistenza in relazione al pianeta terra, alla natura, agli animali e a noi esseri umani. Quammen scrive che si definisce zoonosi ogni infezione animale trasmissibile agli esseri umani, come in passato Hiv-1, l'influenza e ebola o la Sars. Dal 1981 ad oggi le malattie infettive di origine zoonotica hanno causato 30 milioni di morti nel mondo. Ogni cosa, pestilenze incluse, deve avere un'origine e questo testo ne indaga le possibilità. Lo studio sembra confermare la verità darwiniana (sinistra eppure metodicamente dimenticata) che noi umani siamo davvero una specie animale, legata in modo indissolubile alle altre. Si può comprendere, attraverso il discorso storico scientifico, cosa siano Hendra, Nipah, Marburg, i virus dna, quelli rna, i retrovirus, gli hantavirus e i coronavirus; entriamo in contatto con concetti complessi ma qui splendidamente esplicati come lo spillover (il salto interspecifico evolutivo del virus da una specie all'altra), la nozione di ospite serbatoio e quella di ospite amplificatore, le dinamiche di trasmissibilità e virulenza. Quammen ha viaggiato e esplorato regioni e continenti, accompagnando i cacciatori di virus nelle loro investigazioni, interrogando i ricercatori sulle loro sperimentazioni. Ovviamente gli agenti patogeni non agiscono coscientemente, seguono una spinta primordiale alla sopravvivenza e al successo riproduttivo. Quando non c'è un'epidemia in corso, il virus non scompare del tutto, si nasconde, all'interno di organismi ospiti che si differenziano per biodiversità e habitat, rendendo possibile la persistenza e la quiescenza del parassita in natura. Naturalmente, se l'uomo arriva e mette sottosopra una foresta, una giungla o un altro genere di ecosistema, distruggendo e disturbando questo stato entropico, qualcosa, nella catena evolutiva del microorganismo, si altera, dando origine a uno spillover e eventualmente ad un outbreak. Le specie animali, selezionate dal patogeno, rispondono a un criterio biogeografico e genetico: si spostano molto e hanno un sistema immunitario accogliente. La scienza suggerisce che sia bene tenere d'occhio gli animali selvatici, perché mentre li stiamo assediando e accerchiando, ci passano le loro malattie. Quammen sottolinea allora che la crisi che stiamo attraversando ha carattere sanitario e ecologico: la devastazione ambientale, la diffusione della tecnologia e la trasformazione dei modelli sociali e produttivi, la disintegrazione di interi ecosistemi, il consumo di suolo, la crescita incondizionata di insediamenti e popolazione, lo sfruttamento minerario, faunistico, ittico e forestale, sono tutti fattori che hanno costituito un impatto globale insostenibile. La pandemia che stiamo vivendo, scrive quindi Quammen, appoggiandosi a una comunità scientifica in allarme da tempo, è conseguenza diretta di nostre azioni, non di accidenti che ci capitano; sono in definitiva fenomeni che l'essere umano può cambiare da inevitabili a controllabili. È il nostro comportamento individuale ad avere un'influenza decisiva sulla potenzialità e sulla trasmissione dell'infezione. L'incertezza che ora abbiamo davanti può essere affrontata solo con il miglioramento delle basi scientifiche del nostro vivere e con la capacità di risposta della nostra collettività in quanto parte della natura e di una cultura etica e naturale. I virus non ce l'hanno con noi, siamo noi a essere diventati molto visibili, molesti e numerosi. Le epidemie non cessano per cause interne al patogeno, ma per il declino dei contagi nella popolazione. Il fenomeno si diffonde da individuo a individuo e la densità dei soggetti suscettibili al contagio deve scendere sotto una certa soglia per ottenere di avere meno persone malate. Tutti i viventi sono connessi tra loro, l'interconnessione è una parola chiave nella complessità di una pandemia. Gli esseri umani sono parte della natura: credere che il mondo naturale sia distinto da noi è un'idea sbagliata e artificiale. Questo testo ha per tema i virus nella loro specificità e un'ipotesi già acquisita a suo tempo è il timore del Big One, una malattia che gli scienziati lavoravano per scoprire, cercando di rendere le persone, che leggono, più consapevoli e responsabili, più libere di fare mosse intelligenti, per reagire alla minaccia e al disastro.
David Quammen si occupa di divulgazione scientifica e biologia evolutiva. In questo libro racconta cosa siano i virus, se siano da considerare esseri viventi oppure no, e come si sviluppi la loro esistenza in relazione al pianeta terra, alla natura, agli animali e a noi esseri umani. Quammen scrive che si definisce zoonosi ogni infezione animale trasmissibile agli esseri umani, come in passato Hiv-1, l'influenza e ebola o la Sars. Dal 1981 ad oggi le malattie infettive di origine zoonotica hanno causato 30 milioni di morti nel mondo. Ogni cosa, pestilenze incluse, deve avere un'origine e questo testo ne indaga le possibilità. Lo studio sembra confermare la verità darwiniana (sinistra eppure metodicamente dimenticata) che noi umani siamo davvero una specie animale, legata in modo indissolubile alle altre. Si può comprendere, attraverso il discorso storico scientifico, cosa siano Hendra, Nipah, Marburg, i virus dna, quelli rna, i retrovirus, gli hantavirus e i coronavirus; entriamo in contatto con concetti complessi ma qui splendidamente esplicati come lo spillover (il salto interspecifico evolutivo del virus da una specie all'altra), la nozione di ospite serbatoio e quella di ospite amplificatore, le dinamiche di trasmissibilità e virulenza. Quammen ha viaggiato e esplorato regioni e continenti, accompagnando i cacciatori di virus nelle loro investigazioni, interrogando i ricercatori sulle loro sperimentazioni. Ovviamente gli agenti patogeni non agiscono coscientemente, seguono una spinta primordiale alla sopravvivenza e al successo riproduttivo. Quando non c'è un'epidemia in corso, il virus non scompare del tutto, si nasconde, all'interno di organismi ospiti che si differenziano per biodiversità e habitat, rendendo possibile la persistenza e la quiescenza del parassita in natura. Naturalmente, se l'uomo arriva e mette sottosopra una foresta, una giungla o un altro genere di ecosistema, distruggendo e disturbando questo stato entropico, qualcosa, nella catena evolutiva del microorganismo, si altera, dando origine a uno spillover e eventualmente ad un outbreak. Le specie animali, selezionate dal patogeno, rispondono a un criterio biogeografico e genetico: si spostano molto e hanno un sistema immunitario accogliente. La scienza suggerisce che sia bene tenere d'occhio gli animali selvatici, perché mentre li stiamo assediando e accerchiando, ci passano le loro malattie. Quammen sottolinea allora che la crisi che stiamo attraversando ha carattere sanitario e ecologico: la devastazione ambientale, la diffusione della tecnologia e la trasformazione dei modelli sociali e produttivi, la disintegrazione di interi ecosistemi, il consumo di suolo, la crescita incondizionata di insediamenti e popolazione, lo sfruttamento minerario, faunistico, ittico e forestale, sono tutti fattori che hanno costituito un impatto globale insostenibile. La pandemia che stiamo vivendo, scrive quindi Quammen, appoggiandosi a una comunità scientifica in allarme da tempo, è conseguenza diretta di nostre azioni, non di accidenti che ci capitano; sono in definitiva fenomeni che l'essere umano può cambiare da inevitabili a controllabili. È il nostro comportamento individuale ad avere un'influenza decisiva sulla potenzialità e sulla trasmissione dell'infezione. L'incertezza che ora abbiamo davanti può essere affrontata solo con il miglioramento delle basi scientifiche del nostro vivere e con la capacità di risposta della nostra collettività in quanto parte della natura e di una cultura etica e naturale. I virus non ce l'hanno con noi, siamo noi a essere diventati molto visibili, molesti e numerosi. Le epidemie non cessano per cause interne al patogeno, ma per il declino dei contagi nella popolazione. Il fenomeno si diffonde da individuo a individuo e la densità dei soggetti suscettibili al contagio deve scendere sotto una certa soglia per ottenere di avere meno persone malate. Tutti i viventi sono connessi tra loro, l'interconnessione è una parola chiave nella complessità di una pandemia. Gli esseri umani sono parte della natura: credere che il mondo naturale sia distinto da noi è un'idea sbagliata e artificiale. Questo testo ha per tema i virus nella loro specificità e un'ipotesi già acquisita a suo tempo è il timore del Big One, una malattia che gli scienziati lavoravano per scoprire, cercando di rendere le persone, che leggono, più consapevoli e responsabili, più libere di fare mosse intelligenti, per reagire alla minaccia e al disastro.
January 23, 2021
See my review on Booktube.
November 22, 2020
3.5 ☆
Published in 2012, Quammen's Spillover updated and built upon Garrett's work in The Coming Plague, which was released 18 years earlier. His primary concern is the same as Garrett's, and that is the inevitable arrival of the Next Big One (or NBO).
Despite the two authors' common warning, I didn't find reading Spillover to be redundant. The book's title refers to the moment when a pathogen in host species #1 leaps into species #2. This broad definition covers that transmission event whether between animals ("cross-species transmission") or from animal to humans ("zoonosis"). And for the sake of completeness, "anthroponosis" refers to pathogen transmission from human to animals or to another human.
Quammen asserted that the NBO is likely to be viral in origin. Three of the past four epic disease killers were attributable to viruses: smallpox in the 1500s wiped out indigenous peoples throughout the Americas (number of deaths unknown), the 1918-19 influenza pandemic (50 million fatalities), and AIDS which has killed 30 million persons and still counting. The Black Death during the 1300s killed one-third of Europe (25 million estimated) and was likely due to the bubonic plague bacterium. Scientists expect the NBO to have a similar impact in magnitude. By that metric, this 2020 Covid-19 pandemic is likely not the NBO, which is rather daunting considering the toll to date in terms of fatalities and economic costs.
Quammen wrote about bacterial disease zoonosis, such as Lyme disease, but he seemed more fascinated by viruses. Nobel laureate Sir Peter Medewar, a biologist, defined a virus as "a piece of bad news wrapped up in a protein." To a reader who visualizes her favorite ribeye steak upon hearing "protein," this was not an informative description.
Since my local news show regularly displays an image of the Covid-19 cause, crowned in all of its spiky glory, this served as a handy visual reference. First of all, viruses are incredibly tiny and they weren't seen until electron microscopes were invented in the 1930s. Viruses are not quite alive, as a virion (an individual virus particle outside of a host cell) isn't even a cell. No, a virus is technically an obligate intracellular parasite, meaning that it can live it up and replicate only once it hijacks a host cell for its purposes. The virion's innards consist of various proteins and a tiny genome, whose nucleotides contain instructions for replication. The virion's outer surface is called a capsid, which is a protein. The capsid protects the virion's genome as it helps it to breech a host cell's wall, usually injuring it in the process, and it gives the virion its overall shape. The Covid-19 agent is a coronavirus because its spherical capsid with its multiple little spikes resembles its namesake. Those protuberances enable the virion to lock onto its targeted host cells. By the same token, a person's immune system has to create antibodies, white blood cells, that specifically fit those spikes to circumvent the virion's ability to lock onto its target. (An antibody test for Covid-19 only confirms whether a person has been infected by the virus. At this moment in time, lifelong immunity to Covid-19 can not be concluded from a positive antibody test result.)
A virus' genome is either going to be DNA or RNA based. The double-stranded helix shape of DNA makes the virus relatively more stable than a RNA-based version. The latter, as only a single strand, has more flexible genetic instructions and is thus faster to mutate and evolve, discarding iterations which don't achieve its goal of replication. To mitigate the limitations of its tiny genetic programming, RNA viruses are especially inclined to jump between hosts. And since humans are too numerous to ignore, all this explains why RNA viruses are likelier to be zoonotic pathogens than DNA viruses. Some examples of RNA viruses are hantavirus, herpes B, and ebolavirus.
One additional and genetically sly design, however, belongs to retroviruses. A retrovirus is a RNA virus that can reverse transcribe its code into DNA after it breeches a host cell's wall but before it hijacks that cell's nucleus for its replications. This trick results in the retrovirus becoming permanently part of the host cell's DNA. The most notorious retrovirus is HIV-1, which can lead to AIDS. Indeed, if the darn things weren't so injurious to humans, I would likely admire viruses' evolutionary adaptability - no, not truly!
Quammen, of course, included a pathogen parade in Spillover. In Australia, the Hendra (measles) virus killed horses first and then two people. Nipah virus encephalitis erupted among Malaysian pig farmers and then hopscotched to Bangladesh, which has few, if any, pigs. Now I know not to drink date-palm sap, however fresh and "restorative" it may purported to be. He updated Garrett's coverage of Ebola and AIDS research. Of great interest to me was the account of the first coronavirus outbreak, which was SARS (severe acute respiratory syndrome), in 2003.
Since Spillover is about zoonosis, Quammen discussed disease ecology, especially the significance of host or natural reservoirs. We can't eradicate zoonotic pathogens because they take refuge (i.e. hide) in some other hospitable animal species without causing it any long-lasting harm. One great scientific mystery is where the Ebolavirus is biding its time in between its sporadic outbreaks; its natural reservoir has yet to be found. Bats remain the favorite suspect based on scientific hunts in Africa. As there are about 4,000 mammal species, broad diversity in reservoirs, ranging from rodents to primates, exist. But bats are the most common natural reservoirs for viruses and were confirmed as such for 3 of the 5 diseases that I mentioned in the preceding paragraph.
Quammen does not have formal training in the sciences, although many of his previous writings have been scientific in nature. His literature background manifested itself with metaphors like this one -"the busses grind against one another like chummy elephants" - and with a prolonged imaginative account of how HIV-1 spread throughout Africa. I could have done without his personal musings here. Much of Spillover read like a travelogue with his adventures abroad as he followed disease researchers. He was cognizant of the need to educate his readers about the underlying science, so I do feel as though I've attended a lay person's seminar on virology and epidemiology.
There were, however, two major drawbacks with Quammen's lack of scientific training. It appeared as though he believed that his readership not only lacked a scientific background but was actively afraid of science. This tone of voice posed an occasional distraction. The second negative aspect of that tone, which also appeared flippant on many occasions, diminished his credibility with me. For instance, after reading Garrett's description of many bacterial pathogens which have developed resistance to multiple antibiotics, Quammen appeared too casually confident in this misleading, double-pronged assessment: "now that modern antibiotics are widely available, vastly reducing the lethal menace of bacteria, we can guess confidently that the NBO will be a virus too."
I'm including a link to my review for Garrett's The Coming Plague: Newly Emerging Diseases in a World Out of Balance in case you're trying to choose which book to read. I don't regret reading both, but together (totaling about 1,350 pages) they will likely require a substantial commitment of time. Garrett's book is older and written in a clinical / technical style. Garrett, however, has far more scientific credibility than Quammen does with me. In Spillover's favor, it's both more recent and accessible to readers intimidated by science. I agreed with Quammen's conclusion:
If you're a thriving population, living at high density but exposed to new bugs, it's just a matter of time until the NBO arrives.
Published in 2012, Quammen's Spillover updated and built upon Garrett's work in The Coming Plague, which was released 18 years earlier. His primary concern is the same as Garrett's, and that is the inevitable arrival of the Next Big One (or NBO).
Zoonotic pathogens can hide. That's what make them ... so complicated, so problematic.
Ecological disturbances cause diseases to emerge. Shake a tree, and things fall out.
Despite the two authors' common warning, I didn't find reading Spillover to be redundant. The book's title refers to the moment when a pathogen in host species #1 leaps into species #2. This broad definition covers that transmission event whether between animals ("cross-species transmission") or from animal to humans ("zoonosis"). And for the sake of completeness, "anthroponosis" refers to pathogen transmission from human to animals or to another human.
Quammen asserted that the NBO is likely to be viral in origin. Three of the past four epic disease killers were attributable to viruses: smallpox in the 1500s wiped out indigenous peoples throughout the Americas (number of deaths unknown), the 1918-19 influenza pandemic (50 million fatalities), and AIDS which has killed 30 million persons and still counting. The Black Death during the 1300s killed one-third of Europe (25 million estimated) and was likely due to the bubonic plague bacterium. Scientists expect the NBO to have a similar impact in magnitude. By that metric, this 2020 Covid-19 pandemic is likely not the NBO, which is rather daunting considering the toll to date in terms of fatalities and economic costs.
Quammen wrote about bacterial disease zoonosis, such as Lyme disease, but he seemed more fascinated by viruses. Nobel laureate Sir Peter Medewar, a biologist, defined a virus as "a piece of bad news wrapped up in a protein." To a reader who visualizes her favorite ribeye steak upon hearing "protein," this was not an informative description.
Since my local news show regularly displays an image of the Covid-19 cause, crowned in all of its spiky glory, this served as a handy visual reference. First of all, viruses are incredibly tiny and they weren't seen until electron microscopes were invented in the 1930s. Viruses are not quite alive, as a virion (an individual virus particle outside of a host cell) isn't even a cell. No, a virus is technically an obligate intracellular parasite, meaning that it can live it up and replicate only once it hijacks a host cell for its purposes. The virion's innards consist of various proteins and a tiny genome, whose nucleotides contain instructions for replication. The virion's outer surface is called a capsid, which is a protein. The capsid protects the virion's genome as it helps it to breech a host cell's wall, usually injuring it in the process, and it gives the virion its overall shape. The Covid-19 agent is a coronavirus because its spherical capsid with its multiple little spikes resembles its namesake. Those protuberances enable the virion to lock onto its targeted host cells. By the same token, a person's immune system has to create antibodies, white blood cells, that specifically fit those spikes to circumvent the virion's ability to lock onto its target. (An antibody test for Covid-19 only confirms whether a person has been infected by the virus. At this moment in time, lifelong immunity to Covid-19 can not be concluded from a positive antibody test result.)
A virus' genome is either going to be DNA or RNA based. The double-stranded helix shape of DNA makes the virus relatively more stable than a RNA-based version. The latter, as only a single strand, has more flexible genetic instructions and is thus faster to mutate and evolve, discarding iterations which don't achieve its goal of replication. To mitigate the limitations of its tiny genetic programming, RNA viruses are especially inclined to jump between hosts. And since humans are too numerous to ignore, all this explains why RNA viruses are likelier to be zoonotic pathogens than DNA viruses. Some examples of RNA viruses are hantavirus, herpes B, and ebolavirus.
One additional and genetically sly design, however, belongs to retroviruses. A retrovirus is a RNA virus that can reverse transcribe its code into DNA after it breeches a host cell's wall but before it hijacks that cell's nucleus for its replications. This trick results in the retrovirus becoming permanently part of the host cell's DNA. The most notorious retrovirus is HIV-1, which can lead to AIDS. Indeed, if the darn things weren't so injurious to humans, I would likely admire viruses' evolutionary adaptability - no, not truly!
Quammen, of course, included a pathogen parade in Spillover. In Australia, the Hendra (measles) virus killed horses first and then two people. Nipah virus encephalitis erupted among Malaysian pig farmers and then hopscotched to Bangladesh, which has few, if any, pigs. Now I know not to drink date-palm sap, however fresh and "restorative" it may purported to be. He updated Garrett's coverage of Ebola and AIDS research. Of great interest to me was the account of the first coronavirus outbreak, which was SARS (severe acute respiratory syndrome), in 2003.
Since Spillover is about zoonosis, Quammen discussed disease ecology, especially the significance of host or natural reservoirs. We can't eradicate zoonotic pathogens because they take refuge (i.e. hide) in some other hospitable animal species without causing it any long-lasting harm. One great scientific mystery is where the Ebolavirus is biding its time in between its sporadic outbreaks; its natural reservoir has yet to be found. Bats remain the favorite suspect based on scientific hunts in Africa. As there are about 4,000 mammal species, broad diversity in reservoirs, ranging from rodents to primates, exist. But bats are the most common natural reservoirs for viruses and were confirmed as such for 3 of the 5 diseases that I mentioned in the preceding paragraph.
Quammen does not have formal training in the sciences, although many of his previous writings have been scientific in nature. His literature background manifested itself with metaphors like this one -"the busses grind against one another like chummy elephants" - and with a prolonged imaginative account of how HIV-1 spread throughout Africa. I could have done without his personal musings here. Much of Spillover read like a travelogue with his adventures abroad as he followed disease researchers. He was cognizant of the need to educate his readers about the underlying science, so I do feel as though I've attended a lay person's seminar on virology and epidemiology.
There were, however, two major drawbacks with Quammen's lack of scientific training. It appeared as though he believed that his readership not only lacked a scientific background but was actively afraid of science. This tone of voice posed an occasional distraction. The second negative aspect of that tone, which also appeared flippant on many occasions, diminished his credibility with me. For instance, after reading Garrett's description of many bacterial pathogens which have developed resistance to multiple antibiotics, Quammen appeared too casually confident in this misleading, double-pronged assessment: "now that modern antibiotics are widely available, vastly reducing the lethal menace of bacteria, we can guess confidently that the NBO will be a virus too."
I'm including a link to my review for Garrett's The Coming Plague: Newly Emerging Diseases in a World Out of Balance in case you're trying to choose which book to read. I don't regret reading both, but together (totaling about 1,350 pages) they will likely require a substantial commitment of time. Garrett's book is older and written in a clinical / technical style. Garrett, however, has far more scientific credibility than Quammen does with me. In Spillover's favor, it's both more recent and accessible to readers intimidated by science. I agreed with Quammen's conclusion:
We should appreciate that these recent outbreaks of zoonotic diseases, as well as the spread and recurrences of old ones, are part of a larger pattern, and that humanity is responsible for generating that pattern. We should understand that, although some of the human caused factors may seem virtually inexorable, others are within our control.
June 19, 2020
Lodato sii, mio Signore, per nostra sorella madre terra, la quale ci nutre e ci mantiene: produce frutti colorati, fiori ed erba .
Leggere Spillover, per una come me che dovrebbe avere più di una infarinatura scientifica, è simile alla piacevole scoperta, per un austero prof d’Italiano in un liceo classico, di trovare ottima l’esegesi del Paradiso del mai troppo benedetto prof. Bignami ( dico sul serio: era veramente ottima ).
Quammenn, infatti, ha avuto il doppio merito di riportare alla luce nozioni e nomi (uno su tutti: coxiella burneti, l’agente etiologico della febbre Q) persi nella nebbia del passato e di dimostrare che è possibile la divulgazione scientifica “puntuale” e alla portata di una media attenzione.
Se i vari “scienziati” chiamati a spiegarci il Sars Cov2, in questi quattro mesi di pandemia, avessero avuto più dimestichezza con questo linguaggio, senza scadere nella banalizzazione o in loop indistricabili da cui difficilmente usciva qualcosa di coerente, sarebbe stato meglio per loro e per noi.
Certo in alcuni capitoli il nostro divulgatore mi è sembrato Marlow che risalendo i fiumi dei due Congo va alla ricerca di Kurtz, il virus di turno ora Ebola ora HIV, e non ce li vedo i vari “scienzati” di turno in questa veste.
E quanti dei virologi, epidemiologi, immunologi e matematici del racconto hanno la competenza, la passione e l’umiltà di confessare di non sapere. Cosa che non ha avuto la dottoressa Capua la quale, alla chiusura dei voli da e verso la Cina, con un sorrisetto sprezzante di superiorità che manco baffetto D'Alema, ci diceva trattarsi di qualcosa di simile all’influenza. Senza specificare che quello influenzale non è coronavirus ma H1234-N1234 ecc; che è sì a Rna ma ha una velocità di mutare direzione come una trottola che il Sars Cov 2 non ha, errore non da poco per una virologa così “in”, in quanto le mutazioni servono al virus per sopravvivere: non uccidere l'ospite prima di essersi replicato a sufficienza è la legge dell' H1N1 ma non dei corona Sars.
Bene la finisco con le frecciatine lasciandole ai veri scienziati che non le lesinano.
Il valore vero di Spillover è quello di spiegare che non c’è modo per l’uomo di dominare tutto il resto degli esseri viventi, con cui abbiamo legami genetici e “sociali”. Se non ci fosse affinità genetica tra noi e scimpanzé, ratti, pipistrelli, polli e maiali, soprattutto i maiali tra i non antropomorfi, l’Rna virale chiuderebbe bottega.
L’uomo dovrebbe cominciare a imporsi il rispetto di sé nel rispetto del “fratello lupo”.
Leggere Spillover, per una come me che dovrebbe avere più di una infarinatura scientifica, è simile alla piacevole scoperta, per un austero prof d’Italiano in un liceo classico, di trovare ottima l’esegesi del Paradiso del mai troppo benedetto prof. Bignami ( dico sul serio: era veramente ottima ).
Quammenn, infatti, ha avuto il doppio merito di riportare alla luce nozioni e nomi (uno su tutti: coxiella burneti, l’agente etiologico della febbre Q) persi nella nebbia del passato e di dimostrare che è possibile la divulgazione scientifica “puntuale” e alla portata di una media attenzione.
Se i vari “scienziati” chiamati a spiegarci il Sars Cov2, in questi quattro mesi di pandemia, avessero avuto più dimestichezza con questo linguaggio, senza scadere nella banalizzazione o in loop indistricabili da cui difficilmente usciva qualcosa di coerente, sarebbe stato meglio per loro e per noi.
Certo in alcuni capitoli il nostro divulgatore mi è sembrato Marlow che risalendo i fiumi dei due Congo va alla ricerca di Kurtz, il virus di turno ora Ebola ora HIV, e non ce li vedo i vari “scienzati” di turno in questa veste.
E quanti dei virologi, epidemiologi, immunologi e matematici del racconto hanno la competenza, la passione e l’umiltà di confessare di non sapere. Cosa che non ha avuto la dottoressa Capua la quale, alla chiusura dei voli da e verso la Cina, con un sorrisetto sprezzante di superiorità che manco baffetto D'Alema, ci diceva trattarsi di qualcosa di simile all’influenza. Senza specificare che quello influenzale non è coronavirus ma H1234-N1234 ecc; che è sì a Rna ma ha una velocità di mutare direzione come una trottola che il Sars Cov 2 non ha, errore non da poco per una virologa così “in”, in quanto le mutazioni servono al virus per sopravvivere: non uccidere l'ospite prima di essersi replicato a sufficienza è la legge dell' H1N1 ma non dei corona Sars.
Bene la finisco con le frecciatine lasciandole ai veri scienziati che non le lesinano.
Il valore vero di Spillover è quello di spiegare che non c’è modo per l’uomo di dominare tutto il resto degli esseri viventi, con cui abbiamo legami genetici e “sociali”. Se non ci fosse affinità genetica tra noi e scimpanzé, ratti, pipistrelli, polli e maiali, soprattutto i maiali tra i non antropomorfi, l’Rna virale chiuderebbe bottega.
L’uomo dovrebbe cominciare a imporsi il rispetto di sé nel rispetto del “fratello lupo”.
January 11, 2020
This is informative, interesting and entertaining. Parts of it read as a detective story, as the author describes the quest to identify pathogens, and the routes that can lead those pathogens to cause human disease. The approach encompasses the ecological as well as the evolutionary factors that lead to zoonotic diseases.
As I read, I took copious quotes from every chapter. As David Quammen says it much better than I can, I am going to copy some of them here. I will use spoiler tags for my summary notes about what the reservoir host etc. are for viruses, so if you want to read it for yourself, it will come as a surprise.
The passages in italics are tidbits that show the author’s sometimes sarcastic humour which made the book even more enjoyable.
I Pale Horse (Hendra virus)
A zoonosis is an animal infection transmissible to humans. There are more such diseases than you might expect. AIDS is one. Influenza is a whole category of others...This form of interspecies leap is common, not rare; about 60 percent of all human infectious diseases currently known either cross routinely or have recently crossed between other animals and us.
Human-caused ecological pressures and disruptions are bringing animal pathogens ever more into contact with human populations, while human technology and behavior are spreading those pathogens ever more widely and quickly.
II Thirteen Gorillas (Ebola)
Like other zoonotic viruses, ebolaviruses have probably adapted to living tranquilly within their reservoir (or reservoirs), replicating steadily but not abundantly and causing little or no trouble. Spilling over into humans, they encounter a new environment, a new set of circumstances, often causing fatal devastation. And one human can infect another, through direct contact with bodily fluids or other sources of virus. But the chain of ebolavirus infection, at least so far, has never continued through many successive cases, great distances, or long stretches of time. Some scientists use the term “dead-end host,” as distinct from “reservoir host,” to describe humanity’s role in the lives and adventures of ebolaviruses.
Advisory: If your husband catches an ebolavirus, give him food and water and love and maybe prayers but keep your distance, wait patiently, hope for the best—and, if he dies, don’t clean out his bowels by hand. Better to step back, blow a kiss, and burn the hut.
III Everything Comes from Somewhere (Malaria)
Hamer was especially interested in why diseases such as influenza, diphtheria, and measles seem to mount into major outbreaks in a cyclical pattern—rising to a high case count, fading away, rising again after a certain interval of time. What seemed curious was that the interval between outbreaks remained, for a given disease, so constant. The logic of such cycles, Hamer suspected, was that an outbreak declined whenever there weren’t enough susceptible (nonimmune) people left in the population to fuel it, and that another outbreak began as soon as new births had supplied a sufficient number of new victims. Furthermore, it wasn’t the sheer number of susceptible individuals that was crucial, but the density of susceptibles multiplied by the density of infectious people. In other words, contact between those two groups is what mattered.
The four (kinds of malaria) known for targeting humans are transmitted from person to person by Anopheles mosquitoes. These four parasites possess wondrously complicated life histories, encompassing multiple metamorphoses and different forms in series: an asexual stage known as the sporozoite, which enters the human skin during a mosquito bite and migrates to the human liver; another asexual stage known as the merozoite, which emerges from the liver and reproduces in red blood cells; a stage known as the trophozoite, feeding and growing inside the blood cells, each of which fattens as a schizont and then bursts, releasing more merozoites to further multiply in the blood, and causing a spike of fever; a sexual stage known as the gametocyte, differentiated into male and female versions, which emerge from a later round of infected red blood cells, enter the bloodstream en masse, and are taken up within a blood meal by the next mosquito; a fertilized sexual stage known as the ookinete, which lodges in the gut lining of the mosquito, each ookinete ripening into a sort of egg sac filled with sporozoites; and then come the sporozoites again, bursting out of the egg sac and migrating to the mosquito’s salivary glands, where they lurk, ready to surge down the mosquito’s proboscis into another host. If you’ve followed all that, at a quick reading, you have a future in biology.
This elaborate concatenation of life-forms and sequential strategies is highly adaptive and, so far as mosquitoes and hosts are concerned, difficult to resist. It shows evolution’s power, over great lengths of time, to produce structures, tactics, and transformations of majestic intricacy. Alternatively, anyone who favors Intelligent Design in lieu of evolution might pause to wonder why God devoted so much of His intelligence to designing malarial parasites.
IV Dinner at the Rat Farm (SARS)
The very name coined during that early period, SARS, reflects the fact that this thing was known only by its effects, its impacts, like the footprints of a large, invisible beast. Ebola is a virus. Hendra is a virus. Nipah is a virus. SARS is a syndrome.
A superspreader is a patient who, for one reason or another, directly infects far more people than does the typical infected patient.
One further factor, possibly the most crucial, was inherent to the way SARS-CoV affects the human body: Symptoms tend to appear in a person before, rather than after, that person becomes highly infectious. The headache, the fever, and the chills—maybe even the cough—precede the major discharge of virus toward other people..This was an enormously consequential factor in the SARS episode—not just lucky but salvational."
V The Deer, the Parrot, and the Kid Next Door (Q fever, Psittacosis, Lyme disease)
Q fever, or “abattoir’s fever”. It wasn’t a virus, though in some measure it behaved like one. It was a bacterium, but unlike most other bacteria.
First of all, it’s an intracellular bacterium, meaning that it reproduces within cells of its host—as does a virus, though by dissimilar mechanisms—not out in the bloodstream or the gut, where it could be more easily targeted by immune response. Furthermore, it exists in two forms of bacterial particle, one large and one small, each with different characteristics suited to different phases of its life history. The large form replicates prolifically inside host cells and then transmogrifies to the small form, which is tougher and more stable. The small form, almost like a spore, is packaged for survival in the external environment.
Psittacosis. “Parrot fever” a culprit had been identified. It was a small bacterium with some unusual properties, seemingly similar to the agent that causes typhus (Rickettsia prowazekii) and therefore given the name Rickettsia psittaci. (Renamed later Chlamydophila psittaci.)
“If the young cockatoo, after capture, is kept under good conditions,” he and his coauthor wrote, “it remains healthy and presents no danger to human beings.” Likewise, the wild bird populations might carry a high prevalence of infection but suffer little impact in terms of damaged health or mortality. “When, on the other hand, birds are crowded into small spaces, with inadequate food and sunlight, their latent infection is lit up.” The bacterium multiplies and “is excreted in large amounts.” It floats out of the cages along with downy feathers, powdered dung, and dust. It rides the air like a Mosaic plague. People inhale it and become ill.
Lyme disease Part of what makes it problematic is that the life history of Borrelia burgdorferi is very complex, involving much more than ticks and people.
Related to the unchanging fact of noninheritability is a variable that Ostfeld and others call “reservoir competence.” This is the measure of likelihood that a given host animal, if it’s already infected, will transmit the infection to a feeding tick. Reservoir competence varies from species to species, most likely depending on differences in the strength of immune response against the pathogen. If the immune response is weak and the blood teems with spirochetes, that species will serve as a highly “competent” reservoir of B. burgdorferi, transmitting infection to most ticks that bite it. If the immune response is strong and effective, damping down the level of blood-borne spirochetes, that species will be a relatively less competent reservoir. Studies by Ostfeld’s group, involving captive animals and the ticks feeding on them, showed white-footed mice to be the most competent of reservoirs for the Lyme disease spirochete. Chipmunks were a distant second in reservoir competence, with shrews close behind them.
VI Going viral
Expert opinion even divides on the conundrum of whether viruses are alive. If they aren’t, then at the very least they’re mechanistic shortcuts on the principle of life itself. They parasitize. They compete. They attack, they evade. They struggle. They obey the same basic imperatives as all living creatures—to survive, to multiply, to perpetuate their lineage—and they do it using intricate strategies shaped by Darwinian natural selection. They evolve. The viruses on Earth today are well fit for what they do because only the fittest have survived.
R0 = βN/(α + b + v)
In English: The evolutionary success of a bug is directly related to its rate of transmission through the host population and inversely but intricately related to its lethality, the rate of recovery from it, and the normal death rate from all other causes. (The clunky imprecision of that sentence is why ecologists prefer math.) So the first rule of a successful parasite is slightly more complicated than Don’t kill your host. It’s more complicated even than Don’t burn your bridges until after you’ve crossed them. The first rule of a successful parasite is βN/(α + b + v).
And why are RNA genomes so small? Because their self-replication is so fraught with inaccuracies that, given more information to replicate, they would accumulate more errors and cease to function at all. It’s sort of a chicken-and-egg problem, he said. RNA viruses are limited to small genomes because their mutation rates are so high, and their mutation rates are so high because they’re limited to small genomes. In fact, there’s a fancy name for that bind: Eigen’s paradox.
VII Celestial Hosts
From where do these viruses jump? They jump from animals in which they have long abided, found safety, and occasionally gotten stuck. They jump, that is, from their reservoir hosts.
And which animals are those? Some kinds are more deeply implicated than others as reservoirs of the zoonotic viruses that jump into humans. Hantaviruses jump from rodents. Lassa too jumps from rodents. Yellow fever virus jumps from monkeys. Monkeypox, despite its name, seems to jump mainly from squirrels. Herpes B jumps from macaques. The influenzas jump from wild birds into domestic poultry and then into people, sometimes after a transformative stopover in pigs. Measles may originally have jumped into us from domesticated sheep and goats. HIV-1 has jumped our way from chimpanzees. So there’s a certain diversity of origins. But a large fraction of all the scary new viruses I’ve mentioned so far, as well as others I haven’t mentioned, come jumping at us from bats.
Epstein was talking, in an understated way, about the two distinct but interconnected dimensions of zoonotic transfer: ecology and evolution. Habitat disturbance, bushmeat hunting, the exposure of humans to unfamiliar viruses that lurk in animal hosts—that’s ecology. Those things happen between humans and other kinds of organism, and are viewed in the moment. Rates of replication and mutation of an RNA virus, differential success for different strains of the virus, adaptation of the virus to a new host—that’s evolution. It happens within a population of some organism, as the population responds to its environment over time. Among the most important things to remember about evolution—and about its primary mechanism, natural selection, as limned by Darwin and his successors—is that it doesn’t have purposes. It only has results. To believe otherwise is to embrace a teleological fallacy that carries emotive appeal (“the revenge of the rain forest”) but misleads. This is what Jon Epstein was getting at. Don’t imagine that these viruses have a deliberate strategy, he said. Don’t think that they bear some malign onus against humans. “It’s all about opportunity.” They don’t come after us. In one way or another, we go to them.
VIII The chimp and the river (AIDS, HIV-1, HIV-2, SIV)
As the new century began, AIDS researchers pondered this roster of different viral lineages: seven groups of HIV-2 and three groups of HIV-1. The seven groups of HIV-2, distinct as they were from one another, all resembled SIVsm, the virus endemic in sooty mangabeys. (So did the later addition, group H.) The three kinds of HIV-1 all resembled SIVcpz, from chimps. (The eventual fourth kind, group P, is most closely related to SIV from gorillas.) Now here’s the part that, as it percolates into your brain, should cause a shudder: Scientists think that each of those twelve groups (eight of HIV-2, four of HIV-1) reflects an independent instance of cross-species transmission. Twelve spillovers.
In other words, HIV hasn’t happened to humanity just once. It has happened at least a dozen times—a dozen that we know of, and probably many more times in earlier history. Therefore it wasn’t a highly improbable event. It wasn’t a singular piece of vastly unlikely bad luck, striking humankind with devastating results—like a comet come knuckleballing across the infinitude of space to smack planet Earth and extinguish the dinosaurs. No. The arrival of HIV in human bloodstreams was, on the contrary, part of a small trend. Due to the nature of our interactions with African primates, it seems to occur pretty often.
Throughout the rest of the world you see AIDS-education materials crying out: Practice safe sex! Wear a condom! Don’t reuse needles! Here the message was: Don’t eat apes!
IX It depends (Influenza)
Influenza is caused by three types of viruses, of which the most worrisome and widespread is influenza A. Viruses of that type all share certain genetic traits: a single-stranded RNA genome, which is partitioned into eight segments, which serve as templates for eleven different proteins.
Two of those molecules become spiky protuberances from the outer surface of the viral envelope: hemagglutinin and neuraminidase. Those two, recognizable by an immune system, and crucial for penetrating and exiting cells of a host, give the various subtypes of influenza A their definitive labels: H5N1, H1N1, and so on. The term “H5N1” indicates a virus featuring subtype 5 of the hemagglutinin protein combined with subtype 1 of the neuraminidase protein. Sixteen different kinds of hemagglutinin, plus nine kinds of neuraminidase, have been detected in the natural world. Hemagglutinin is the key that unlocks a cell membrane so that the virus can get in, and neuraminidase is the key for getting back out. Okay so far? Having absorbed this simple paragraph, you understand more about influenza than 99.9 percent of the people on Earth. Pat yourself on the back and get a flu shot in November.
One of the things that makes influenza so problematic, Webster said, is its propensity to change. He explained. First of all there’s the high rate of mutation, as in any RNA virus. No quality control as it replicates, he said, echoing what I’d heard from Eddie Holmes. Continual copying errors at the level of individual letters of code. But that’s not the half of it. Even more important is the reassortment. (“Reassortment” means the accidental swapping of entire genomic segments between virions of two different subtypes. It’s similar to recombination, as occurs sometimes between crossed chromosomes in dividing cells, except that reassortment is somewhat more facile and orderly. It happens often among influenza viruses because the segmentation allows their RNA to snap apart neatly at the points of demarcation between genes: those eight railroad cars in a switching yard.) Sixteen available kinds of hemagglutinin, Webster reminded me. Nine kinds of neuraminidase. “You can do the arithmetic,” he said. (I did: 144 possible pairings.) The changes are random and most yield bad combinations, making the virus less viable. But random changes do constitute variation, and variation is the exploration of possibilities. It’s the raw material of natural selection, adaptation, evolution. That’s why influenza is such a protean sort of bug, always full of surprises, full of newness, full of menace: so much mutation and reassortment.
The steady incidence of mutations yields incremental change in how the virus looks and behaves. Ergo you need another flu shot every autumn: This year’s version of flu is different enough from last year’s. Reassortment yields big changes. Such major innovations by reassortment, introducing new subtypes, which may be infectious but unfamiliar to the human population, are what generally lead to pandemics.
If you have read through my admittedly long review, or just scrolled through, I have a few words of advice:
Don’t go into a bat cave without a hazmat suit.
Don’t feed the monkeys in shrines, generally keep your distance from them.
Don’t eat apes.
Practice safe sex, and take your yearly flu shot.
As I read, I took copious quotes from every chapter. As David Quammen says it much better than I can, I am going to copy some of them here. I will use spoiler tags for my summary notes about what the reservoir host etc. are for viruses, so if you want to read it for yourself, it will come as a surprise.
The passages in italics are tidbits that show the author’s sometimes sarcastic humour which made the book even more enjoyable.
I Pale Horse (Hendra virus)
A zoonosis is an animal infection transmissible to humans. There are more such diseases than you might expect. AIDS is one. Influenza is a whole category of others...This form of interspecies leap is common, not rare; about 60 percent of all human infectious diseases currently known either cross routinely or have recently crossed between other animals and us.
Human-caused ecological pressures and disruptions are bringing animal pathogens ever more into contact with human populations, while human technology and behavior are spreading those pathogens ever more widely and quickly.
II Thirteen Gorillas (Ebola)
Like other zoonotic viruses, ebolaviruses have probably adapted to living tranquilly within their reservoir (or reservoirs), replicating steadily but not abundantly and causing little or no trouble. Spilling over into humans, they encounter a new environment, a new set of circumstances, often causing fatal devastation. And one human can infect another, through direct contact with bodily fluids or other sources of virus. But the chain of ebolavirus infection, at least so far, has never continued through many successive cases, great distances, or long stretches of time. Some scientists use the term “dead-end host,” as distinct from “reservoir host,” to describe humanity’s role in the lives and adventures of ebolaviruses.
Advisory: If your husband catches an ebolavirus, give him food and water and love and maybe prayers but keep your distance, wait patiently, hope for the best—and, if he dies, don’t clean out his bowels by hand. Better to step back, blow a kiss, and burn the hut.
III Everything Comes from Somewhere (Malaria)
Hamer was especially interested in why diseases such as influenza, diphtheria, and measles seem to mount into major outbreaks in a cyclical pattern—rising to a high case count, fading away, rising again after a certain interval of time. What seemed curious was that the interval between outbreaks remained, for a given disease, so constant. The logic of such cycles, Hamer suspected, was that an outbreak declined whenever there weren’t enough susceptible (nonimmune) people left in the population to fuel it, and that another outbreak began as soon as new births had supplied a sufficient number of new victims. Furthermore, it wasn’t the sheer number of susceptible individuals that was crucial, but the density of susceptibles multiplied by the density of infectious people. In other words, contact between those two groups is what mattered.
The four (kinds of malaria) known for targeting humans are transmitted from person to person by Anopheles mosquitoes. These four parasites possess wondrously complicated life histories, encompassing multiple metamorphoses and different forms in series: an asexual stage known as the sporozoite, which enters the human skin during a mosquito bite and migrates to the human liver; another asexual stage known as the merozoite, which emerges from the liver and reproduces in red blood cells; a stage known as the trophozoite, feeding and growing inside the blood cells, each of which fattens as a schizont and then bursts, releasing more merozoites to further multiply in the blood, and causing a spike of fever; a sexual stage known as the gametocyte, differentiated into male and female versions, which emerge from a later round of infected red blood cells, enter the bloodstream en masse, and are taken up within a blood meal by the next mosquito; a fertilized sexual stage known as the ookinete, which lodges in the gut lining of the mosquito, each ookinete ripening into a sort of egg sac filled with sporozoites; and then come the sporozoites again, bursting out of the egg sac and migrating to the mosquito’s salivary glands, where they lurk, ready to surge down the mosquito’s proboscis into another host. If you’ve followed all that, at a quick reading, you have a future in biology.
This elaborate concatenation of life-forms and sequential strategies is highly adaptive and, so far as mosquitoes and hosts are concerned, difficult to resist. It shows evolution’s power, over great lengths of time, to produce structures, tactics, and transformations of majestic intricacy. Alternatively, anyone who favors Intelligent Design in lieu of evolution might pause to wonder why God devoted so much of His intelligence to designing malarial parasites.
IV Dinner at the Rat Farm (SARS)
The very name coined during that early period, SARS, reflects the fact that this thing was known only by its effects, its impacts, like the footprints of a large, invisible beast. Ebola is a virus. Hendra is a virus. Nipah is a virus. SARS is a syndrome.
A superspreader is a patient who, for one reason or another, directly infects far more people than does the typical infected patient.
One further factor, possibly the most crucial, was inherent to the way SARS-CoV affects the human body: Symptoms tend to appear in a person before, rather than after, that person becomes highly infectious. The headache, the fever, and the chills—maybe even the cough—precede the major discharge of virus toward other people..This was an enormously consequential factor in the SARS episode—not just lucky but salvational."
V The Deer, the Parrot, and the Kid Next Door (Q fever, Psittacosis, Lyme disease)
Q fever, or “abattoir’s fever”. It wasn’t a virus, though in some measure it behaved like one. It was a bacterium, but unlike most other bacteria.
First of all, it’s an intracellular bacterium, meaning that it reproduces within cells of its host—as does a virus, though by dissimilar mechanisms—not out in the bloodstream or the gut, where it could be more easily targeted by immune response. Furthermore, it exists in two forms of bacterial particle, one large and one small, each with different characteristics suited to different phases of its life history. The large form replicates prolifically inside host cells and then transmogrifies to the small form, which is tougher and more stable. The small form, almost like a spore, is packaged for survival in the external environment.
Psittacosis. “Parrot fever” a culprit had been identified. It was a small bacterium with some unusual properties, seemingly similar to the agent that causes typhus (Rickettsia prowazekii) and therefore given the name Rickettsia psittaci. (Renamed later Chlamydophila psittaci.)
“If the young cockatoo, after capture, is kept under good conditions,” he and his coauthor wrote, “it remains healthy and presents no danger to human beings.” Likewise, the wild bird populations might carry a high prevalence of infection but suffer little impact in terms of damaged health or mortality. “When, on the other hand, birds are crowded into small spaces, with inadequate food and sunlight, their latent infection is lit up.” The bacterium multiplies and “is excreted in large amounts.” It floats out of the cages along with downy feathers, powdered dung, and dust. It rides the air like a Mosaic plague. People inhale it and become ill.
Lyme disease Part of what makes it problematic is that the life history of Borrelia burgdorferi is very complex, involving much more than ticks and people.
Related to the unchanging fact of noninheritability is a variable that Ostfeld and others call “reservoir competence.” This is the measure of likelihood that a given host animal, if it’s already infected, will transmit the infection to a feeding tick. Reservoir competence varies from species to species, most likely depending on differences in the strength of immune response against the pathogen. If the immune response is weak and the blood teems with spirochetes, that species will serve as a highly “competent” reservoir of B. burgdorferi, transmitting infection to most ticks that bite it. If the immune response is strong and effective, damping down the level of blood-borne spirochetes, that species will be a relatively less competent reservoir. Studies by Ostfeld’s group, involving captive animals and the ticks feeding on them, showed white-footed mice to be the most competent of reservoirs for the Lyme disease spirochete. Chipmunks were a distant second in reservoir competence, with shrews close behind them.
VI Going viral
Expert opinion even divides on the conundrum of whether viruses are alive. If they aren’t, then at the very least they’re mechanistic shortcuts on the principle of life itself. They parasitize. They compete. They attack, they evade. They struggle. They obey the same basic imperatives as all living creatures—to survive, to multiply, to perpetuate their lineage—and they do it using intricate strategies shaped by Darwinian natural selection. They evolve. The viruses on Earth today are well fit for what they do because only the fittest have survived.
R0 = βN/(α + b + v)
In English: The evolutionary success of a bug is directly related to its rate of transmission through the host population and inversely but intricately related to its lethality, the rate of recovery from it, and the normal death rate from all other causes. (The clunky imprecision of that sentence is why ecologists prefer math.) So the first rule of a successful parasite is slightly more complicated than Don’t kill your host. It’s more complicated even than Don’t burn your bridges until after you’ve crossed them. The first rule of a successful parasite is βN/(α + b + v).
And why are RNA genomes so small? Because their self-replication is so fraught with inaccuracies that, given more information to replicate, they would accumulate more errors and cease to function at all. It’s sort of a chicken-and-egg problem, he said. RNA viruses are limited to small genomes because their mutation rates are so high, and their mutation rates are so high because they’re limited to small genomes. In fact, there’s a fancy name for that bind: Eigen’s paradox.
VII Celestial Hosts
From where do these viruses jump? They jump from animals in which they have long abided, found safety, and occasionally gotten stuck. They jump, that is, from their reservoir hosts.
And which animals are those? Some kinds are more deeply implicated than others as reservoirs of the zoonotic viruses that jump into humans. Hantaviruses jump from rodents. Lassa too jumps from rodents. Yellow fever virus jumps from monkeys. Monkeypox, despite its name, seems to jump mainly from squirrels. Herpes B jumps from macaques. The influenzas jump from wild birds into domestic poultry and then into people, sometimes after a transformative stopover in pigs. Measles may originally have jumped into us from domesticated sheep and goats. HIV-1 has jumped our way from chimpanzees. So there’s a certain diversity of origins. But a large fraction of all the scary new viruses I’ve mentioned so far, as well as others I haven’t mentioned, come jumping at us from bats.
Epstein was talking, in an understated way, about the two distinct but interconnected dimensions of zoonotic transfer: ecology and evolution. Habitat disturbance, bushmeat hunting, the exposure of humans to unfamiliar viruses that lurk in animal hosts—that’s ecology. Those things happen between humans and other kinds of organism, and are viewed in the moment. Rates of replication and mutation of an RNA virus, differential success for different strains of the virus, adaptation of the virus to a new host—that’s evolution. It happens within a population of some organism, as the population responds to its environment over time. Among the most important things to remember about evolution—and about its primary mechanism, natural selection, as limned by Darwin and his successors—is that it doesn’t have purposes. It only has results. To believe otherwise is to embrace a teleological fallacy that carries emotive appeal (“the revenge of the rain forest”) but misleads. This is what Jon Epstein was getting at. Don’t imagine that these viruses have a deliberate strategy, he said. Don’t think that they bear some malign onus against humans. “It’s all about opportunity.” They don’t come after us. In one way or another, we go to them.
VIII The chimp and the river (AIDS, HIV-1, HIV-2, SIV)
As the new century began, AIDS researchers pondered this roster of different viral lineages: seven groups of HIV-2 and three groups of HIV-1. The seven groups of HIV-2, distinct as they were from one another, all resembled SIVsm, the virus endemic in sooty mangabeys. (So did the later addition, group H.) The three kinds of HIV-1 all resembled SIVcpz, from chimps. (The eventual fourth kind, group P, is most closely related to SIV from gorillas.) Now here’s the part that, as it percolates into your brain, should cause a shudder: Scientists think that each of those twelve groups (eight of HIV-2, four of HIV-1) reflects an independent instance of cross-species transmission. Twelve spillovers.
In other words, HIV hasn’t happened to humanity just once. It has happened at least a dozen times—a dozen that we know of, and probably many more times in earlier history. Therefore it wasn’t a highly improbable event. It wasn’t a singular piece of vastly unlikely bad luck, striking humankind with devastating results—like a comet come knuckleballing across the infinitude of space to smack planet Earth and extinguish the dinosaurs. No. The arrival of HIV in human bloodstreams was, on the contrary, part of a small trend. Due to the nature of our interactions with African primates, it seems to occur pretty often.
Throughout the rest of the world you see AIDS-education materials crying out: Practice safe sex! Wear a condom! Don’t reuse needles! Here the message was: Don’t eat apes!
IX It depends (Influenza)
Influenza is caused by three types of viruses, of which the most worrisome and widespread is influenza A. Viruses of that type all share certain genetic traits: a single-stranded RNA genome, which is partitioned into eight segments, which serve as templates for eleven different proteins.
Two of those molecules become spiky protuberances from the outer surface of the viral envelope: hemagglutinin and neuraminidase. Those two, recognizable by an immune system, and crucial for penetrating and exiting cells of a host, give the various subtypes of influenza A their definitive labels: H5N1, H1N1, and so on. The term “H5N1” indicates a virus featuring subtype 5 of the hemagglutinin protein combined with subtype 1 of the neuraminidase protein. Sixteen different kinds of hemagglutinin, plus nine kinds of neuraminidase, have been detected in the natural world. Hemagglutinin is the key that unlocks a cell membrane so that the virus can get in, and neuraminidase is the key for getting back out. Okay so far? Having absorbed this simple paragraph, you understand more about influenza than 99.9 percent of the people on Earth. Pat yourself on the back and get a flu shot in November.
One of the things that makes influenza so problematic, Webster said, is its propensity to change. He explained. First of all there’s the high rate of mutation, as in any RNA virus. No quality control as it replicates, he said, echoing what I’d heard from Eddie Holmes. Continual copying errors at the level of individual letters of code. But that’s not the half of it. Even more important is the reassortment. (“Reassortment” means the accidental swapping of entire genomic segments between virions of two different subtypes. It’s similar to recombination, as occurs sometimes between crossed chromosomes in dividing cells, except that reassortment is somewhat more facile and orderly. It happens often among influenza viruses because the segmentation allows their RNA to snap apart neatly at the points of demarcation between genes: those eight railroad cars in a switching yard.) Sixteen available kinds of hemagglutinin, Webster reminded me. Nine kinds of neuraminidase. “You can do the arithmetic,” he said. (I did: 144 possible pairings.) The changes are random and most yield bad combinations, making the virus less viable. But random changes do constitute variation, and variation is the exploration of possibilities. It’s the raw material of natural selection, adaptation, evolution. That’s why influenza is such a protean sort of bug, always full of surprises, full of newness, full of menace: so much mutation and reassortment.
The steady incidence of mutations yields incremental change in how the virus looks and behaves. Ergo you need another flu shot every autumn: This year’s version of flu is different enough from last year’s. Reassortment yields big changes. Such major innovations by reassortment, introducing new subtypes, which may be infectious but unfamiliar to the human population, are what generally lead to pandemics.
If you have read through my admittedly long review, or just scrolled through, I have a few words of advice:
Don’t go into a bat cave without a hazmat suit.
Don’t feed the monkeys in shrines, generally keep your distance from them.
Don’t eat apes.
Practice safe sex, and take your yearly flu shot.
April 8, 2020
This exposé of zoonoses (diseases passed from animals to humans) is top-notch scientific journalism: pacey, well-structured and entirely gripping. Although it’s a rather sobering topic, this is not scare-mongering for the sake of it; indeed, Quammen frankly concludes that we are much more likely to die of heart disease or fatal car crashes: “Yes, we are all gonna die. Yes. We are all gonna pay taxes and we are all gonna die. Most of us, though, will probably die of something much more mundane than a new virus lately emerged from a duck or a chimpanzee or a bat.” Still, you can’t help but wonder: what will be the next major pandemic? When, where and how will it happen; how severe could it be?
March 7, 2020
Overall: This book is an absolute masterpiece. Epic in scope, brilliant in how it is all connected, very relevant to today, and extremely eye opening and illuminating. Not an easy read but absolutely worth it! 10/10
Summary:
“When a pathogen leaps from some nonhuman animal into a person, and succeeds there in establishing itself as an infectious presence, sometimes causing illness or death, the result is a zoonosis.”
Much of this story is detailing Quammen's adventures and research following various zoonosis around the world.
Fun fact: Historically, some 60 percent of the infections that plague humankind, from influenza to H.I.V. and bubonic plague, all originated in the bodies of other animals.
This book is neatly divided into sections based around a certain zoonosis or a group of similar ones. Each section is a meticulous telling of the origin, history, pertinent findings and research, development, and current state of these various zoonotic diseases.
Take home message: eat more plants and chocolate!
Note: though this book is all about zoonosis it should not cause the reader to panic or be scared about them. “Spillover” hardly touches on such pandemic-worthy animal pathogens as avian flu or multi-drug-resistant bacteria, rather, it fully describes the unfolding convergence between veterinary science and human medicine, and how veterinary-minded medical experts discover and track diseases that spread across species. “Spillover” is less public health warning than ecological affirmation: these crossovers force us to uphold “the old Darwinian truth (the darkest of his truths, well known and persistently forgotten) that humanity is a kind of animal” — with a shared fate on the planet. “People and gorillas, horses and duikers and pigs, monkeys and chimps and bats and viruses,” Quammen writes. “We’re all in this together.”
The Good: I loved this book! Granted it is a subject I am very interested in but I listened to it with my husband who has no medical or animal background, and he immensely enjoyed it as well. The storytelling is amazing, it really does read like a narrative and I felt swept away at many points that I had to remind myself this was nonfiction. Another major positive is the scope. This book has SO MUCH information and yes, you absolutely have to pay attention, but the author does a great job at bringing everything together and explaining difficult to understand topics. It is a blend of science, history, ecology, anthropology, immunology, research, and all presented cohesively in a narrative that grips you with every chapter. My favorite section of all was Ebola. Overall, this book is phenomenal, very relevant to current events, and I learned so much while listening to it. Highly recommend.
The Bad: There were a few chapters in the section on AIDS that the author was speculating and theorizing that I was not a fan of. I preferred the remainder of the book which was all based on facts and science that I found these few chapters distracting and out of place. Some sections are dense in material that you really do need to be paying attention in order to keep up. I found this to be a positive though as I really learned a lot while reading this book.
Favorite Quotes:
“Make no mistake, they are connected, these disease outbreaks coming one after another. And they are not simply happening to us; they represent the unintended results of things we are doing. They reflect the convergence of two forms of crisis on our planet. The first crisis is ecological, the second is medical.”
“Our findings highlight the critical need for health monitoring and identification of new, potentially zoonotic pathogens in wildlife populations, as a forecast measure for EIDs.” That sounds reasonable: Let’s keep an eye on wild creatures. As we besiege them, as we corner them, as we exterminate them and eat them, we’re getting their diseases.”
“People and gorillas, horses and duikers and pigs, monkeys and chimps and bats and viruses: We’re all in this together.”
“Disappointment, in science, is sometimes a gateway to insight.”
Summary:
“When a pathogen leaps from some nonhuman animal into a person, and succeeds there in establishing itself as an infectious presence, sometimes causing illness or death, the result is a zoonosis.”
Much of this story is detailing Quammen's adventures and research following various zoonosis around the world.
Fun fact: Historically, some 60 percent of the infections that plague humankind, from influenza to H.I.V. and bubonic plague, all originated in the bodies of other animals.
This book is neatly divided into sections based around a certain zoonosis or a group of similar ones. Each section is a meticulous telling of the origin, history, pertinent findings and research, development, and current state of these various zoonotic diseases.
Take home message: eat more plants and chocolate!
Note: though this book is all about zoonosis it should not cause the reader to panic or be scared about them. “Spillover” hardly touches on such pandemic-worthy animal pathogens as avian flu or multi-drug-resistant bacteria, rather, it fully describes the unfolding convergence between veterinary science and human medicine, and how veterinary-minded medical experts discover and track diseases that spread across species. “Spillover” is less public health warning than ecological affirmation: these crossovers force us to uphold “the old Darwinian truth (the darkest of his truths, well known and persistently forgotten) that humanity is a kind of animal” — with a shared fate on the planet. “People and gorillas, horses and duikers and pigs, monkeys and chimps and bats and viruses,” Quammen writes. “We’re all in this together.”
The Good: I loved this book! Granted it is a subject I am very interested in but I listened to it with my husband who has no medical or animal background, and he immensely enjoyed it as well. The storytelling is amazing, it really does read like a narrative and I felt swept away at many points that I had to remind myself this was nonfiction. Another major positive is the scope. This book has SO MUCH information and yes, you absolutely have to pay attention, but the author does a great job at bringing everything together and explaining difficult to understand topics. It is a blend of science, history, ecology, anthropology, immunology, research, and all presented cohesively in a narrative that grips you with every chapter. My favorite section of all was Ebola. Overall, this book is phenomenal, very relevant to current events, and I learned so much while listening to it. Highly recommend.
The Bad: There were a few chapters in the section on AIDS that the author was speculating and theorizing that I was not a fan of. I preferred the remainder of the book which was all based on facts and science that I found these few chapters distracting and out of place. Some sections are dense in material that you really do need to be paying attention in order to keep up. I found this to be a positive though as I really learned a lot while reading this book.
Favorite Quotes:
“Make no mistake, they are connected, these disease outbreaks coming one after another. And they are not simply happening to us; they represent the unintended results of things we are doing. They reflect the convergence of two forms of crisis on our planet. The first crisis is ecological, the second is medical.”
“Our findings highlight the critical need for health monitoring and identification of new, potentially zoonotic pathogens in wildlife populations, as a forecast measure for EIDs.” That sounds reasonable: Let’s keep an eye on wild creatures. As we besiege them, as we corner them, as we exterminate them and eat them, we’re getting their diseases.”
“People and gorillas, horses and duikers and pigs, monkeys and chimps and bats and viruses: We’re all in this together.”
“Disappointment, in science, is sometimes a gateway to insight.”
March 31, 2020
ma sì, facciamoci del male
April 20, 2020
Alcune frasi tratte dalla conclusione del libro, dal titolo Dipende...
Tra parentesi, nessuno degli esperti contesta il fatto che il prossimo Big One, se accadrà, sarà una zoonosi.
...in particolare i coronavirus - "devono essere considerati serie minacce alla salute pubblica...
"Le azioni dei singoli, siano uomini o farfalle, hanno un grande effetto su R0... Se si tiene costante il tasso medio di trasmissione, basta aggiungere eterogeneità per ridurre il tasso globale di infezione" Sembra un arido teorema, ma in altre parole significa che gli sforzi e le scelte ponderate dei singoli possono avere grande importanza al fine di scongiurare la catastrofe che potrebbe ucciderci come mosche.
Il libro è scritto molto bene, l'ho letto lentamente, sia perché è lungo, sia perché potrebbe essere tranquillamente la trama di una serie TV di almeno una quarantina di episodi. Va preso con un po' di calma.
Le serie corrispondono alle malattie virali per zoonosi: Hendra, Nipah, Ebola, HIV, Sars-COV, influenza aviaria, dove l'autore ripercorre, passando dalle esplorazioni sul luogo delle possibile origini ai laboratori di ricerca, l'evoluzione di queste patologie, con i personaggi, veri o immaginari, che hanno dato il via alla diffusione, alla loro scoperta, al loro studio per poterle contrastare.
E' un "romanzo" della vita nelle sue ancestrali azioni evolutive, inquietante perché queste malattie colpiscono con esserini invisibili, difficili da trovare e gestire, sempre pronti a riformularsi per avere a disposizione un proprio spazio nel mondo.
Nel nostro caso non fa differenza chi siamo, per loro unicamente animali come gli altri, una casa dove abitare per svilupparsi, riprodursi e annientarci.
Lettura interessante per approfondire l'attualità.
Tra parentesi, nessuno degli esperti contesta il fatto che il prossimo Big One, se accadrà, sarà una zoonosi.
...in particolare i coronavirus - "devono essere considerati serie minacce alla salute pubblica...
"Le azioni dei singoli, siano uomini o farfalle, hanno un grande effetto su R0... Se si tiene costante il tasso medio di trasmissione, basta aggiungere eterogeneità per ridurre il tasso globale di infezione" Sembra un arido teorema, ma in altre parole significa che gli sforzi e le scelte ponderate dei singoli possono avere grande importanza al fine di scongiurare la catastrofe che potrebbe ucciderci come mosche.
Il libro è scritto molto bene, l'ho letto lentamente, sia perché è lungo, sia perché potrebbe essere tranquillamente la trama di una serie TV di almeno una quarantina di episodi. Va preso con un po' di calma.
Le serie corrispondono alle malattie virali per zoonosi: Hendra, Nipah, Ebola, HIV, Sars-COV, influenza aviaria, dove l'autore ripercorre, passando dalle esplorazioni sul luogo delle possibile origini ai laboratori di ricerca, l'evoluzione di queste patologie, con i personaggi, veri o immaginari, che hanno dato il via alla diffusione, alla loro scoperta, al loro studio per poterle contrastare.
E' un "romanzo" della vita nelle sue ancestrali azioni evolutive, inquietante perché queste malattie colpiscono con esserini invisibili, difficili da trovare e gestire, sempre pronti a riformularsi per avere a disposizione un proprio spazio nel mondo.
Nel nostro caso non fa differenza chi siamo, per loro unicamente animali come gli altri, una casa dove abitare per svilupparsi, riprodursi e annientarci.
Lettura interessante per approfondire l'attualità.
April 18, 2020
I came here to understand Sars/Covid, but I learned a whole lot more! It's a fascinating book with so much rich information. And then a kicker at the end--maybe we humans are the pandemic.
August 13, 2016
Avevo già letto qualche tempo fa un saggio del giornalista scientifico e inviato del National Geographic David Quammen (nato a Cincinnati, in Ohio, nel 1948): l'argomento era il lungo e tortuoso cammino che portò Darwin alla formulazione della sua teoria e devo dire che il libro mi aveva colpito favorevolmente, senza entusiasmarmi troppo. Perciò ero ben contento di leggere, insieme al GdL saggistica del gruppo GR Italia, l'ultimo saggio del nostro autore. Beh, confesso di averlo nettamente sottovalutato: Spillover è un vero capolavoro di divulgazione scientifica, affascinante, rigoroso, esauriente, chiarissimo, scritto molto bene e incredibilmente avvincente. L'ho letto in soli due giorni: preciso che ero in vacanza, quindi avevo molto tempo libero, tuttavia l'ho letteralmente divorato!
Il tema centrale – epidemie e pandemie che nel passato e nel presente hanno colpito gli esseri umani e quelle che potrebbero farlo nell'immediato futuro – è tra i più attuali e interessanti. Quammen mette in campo un buon numero di fonti per raccontarci la storia delle malattie infettive umane di originale animale, le cosiddette zoonosi: la cronaca o la ricostruzione giornalistica, le testimonianze delle vittime e le interviste agli specialisti, gli articoli e i saggi scientifici, e infine il racconto delle proprie esperienze al seguito dei "cacciatori di virus".
Una prova dell'abilità mostrata da Quammen nel costruire questo saggio si ha subito nel primo capitolo, che funge anche da prologo, in cui si narra della comparsa, nel settembre 2004, di un nuovo, misterioso, virus che attaccò e uccise numerosi cavalli prima di colpire alcuni esseri umani. La vicenda del virus Hendra - dal nome del sobborgo di Brisbane, nello stato australiano del Queensland, teatro della storia - viene assunta a case-study e fornisce a Quammen lo spunto per fornire le prime informazioni e mostrare al lettore come gli scienziati procedono per identificare le cause di una malattia e gli agenti (virali o batterici) che ne sono responsabili. Proprio nel primo capitolo vengono definiti i tre concetti chiave dell'intero saggio: zoonosi, malattia emergente e spillover, il salto di specie che l'agente patogeno può fare quando si verificano certe condizioni ideali (per lui, meno per chi ne viene colpito). Quammen sottolinea più volte che sono zoonosi quasi tutte le epidemie e pandemie che hanno colpito gli esseri umani nel corso dei secoli, in particolare negli ultimi 150 anni: tutti i tipi di influenza (compresa la famigerata spagnola, che tra il 1918 e il 1920 si stima abbia ucciso circa 50 milioni di individui in tutto il globo), la SARS, l'AIDS, la peste bubbonica, la rabbia, la malaria, il morbo di Lyme, l'antrace, le malattie causate dai virus Ebola, Marburg, Nipah etc. L'elenco è lunghissimo, e ci rammenta due cose importanti, dice Quammen: la prima è che l'uomo è un animale che al pari di cavalli, maiali e scimmie può essere infettato dagli stessi patogeni, opportunamenti mutati; la seconda è che il Next Big One, la prossima malattia emergente che diventerà per l'Homo Sapiens una pandemia, potrebbe essere con ogni probabilità una zoonosi.
Credo che non si possa esagerare l'importanza delle riflessioni sulla stretta correlazione tra le zoonosi emergenti potenzialmente distruttive e l'impatto di Homo sapiens sul resto della biosfera (dal consumo del suolo alla disintegrazione degli ecosistemi, dall'inquinamento al riscaldamento globale, dallo sfruttamento indiscriminato delle risorse naturali alla sovrappopolazione). Secondo molti studiosi intervistati da Quammen, ci stiamo in un certo senso scavando la fossa da soli: sterminando le specie selvatiche, sostituendole con quelle addomesticate e aumentando noi stessi di numero, stiamo fornendo a virus e batteri un nuovo terreno di caccia, in cui le prede siamo noi stessi. Molto illuminante, a questo proposito, è il racconto delle abitudini culinarie dei cinesi meridionali, avidissimi di cibi esotici preparati con creature selvatiche nel cap. 4.
La curiosità del lettore viene adeguatamente stimolata dai racconti delle spedizioni dei cacciatori di virus alle quali Quammen partecipa come testimone, e spesso come collaboratore: i tortuosi itinerari congolesi del team del biologo Mike Fay sulle tracce di Ebola e dei gorilla scomparsi (cap. 2); la caccia ai pipistrelli ferro di cavallo a Guilin, vicino Canton, al seguito del biologo Aleksei Chmura per scoprire di più sul virus della SARS (cap. 4); la cattura di macachi nel Santuario delle Scimmie di Sylhet, in Bangladesh, al seguito della squadra dei coniugi Jones-Engel alla ricerca dell'herpes B, patogeno che sembra colpire quasi esclusivamente ricercatori in virologia (cap. 6), etc. Nonostante i pericoli, che non provengono soltanto dai virus, ma anche dagli animali stessi (provate voi a imprigionare una decina di scimmie furibonde), Quammen ci dà un quadro molto realistico di cosa significa occuparsi di epidemiologia, immunologia e virologia, comunicandoci anche qualche particolare piuttosto curioso, come il fatto che i pipistrelli se ne stiano tranquilli appesi dentro a un sacchetto di tela. I cacciatori di virus costituiscono in realtà un gruppo molto eterogeneo: oltre ai biologi, agli etologi e agli zoologi che lavorano sul campo con gli animali, ci sono i medici e gli infermieri che curano gli ammalati, i ricercatori che isolano i patogeni in laboratorio e gli analisti che li studiano tra teoria ed esperimento. Quammen è molto attento a restituirci, nelle numerose interviste incluse nel saggio, il lato umano di tutti questi scienziati, impegnati in prima linea contro minacce microscopiche ma letali.
Tra i "personaggi" di questo libro che mi hanno colpito di più il già citato Mike Fay, instancabile ricercatore che attraversa a piedi la giungla del Congo dividendo il suo lavoro tra raccolta dei campioni ed assistenza alle vittime dell'Ebola (cap. 2), Aleksei Chmura con cui Quammen ha un'interessante discussione sui limiti gastronomici della nostra specie (cap. 4), gli ingegnosi coniugi Cox-Singh che si sono inventati un nuovo modo per catturare il DNA in assenza di apparecchiature sofisticate (cap. 3), la coraggiosa infettivologa Brenda Ang, tra i primi a fronteggiare l'epidemia di SARS tra il 2002 e il 2003 (cap. 4), il virologo australiano e premio Nobel Frank Macfarlane Burnet, scopritore degli agenti infettivi della febbre Q e della psittacosi (cap. 5), Edward C. Holmes, il massimo esperto mondiale di virus a RNA (cap. 6), la ricercatrice Kelly Warfield, il cui incidente in laboratorio e la successiva quarantena è raccontato con accenti molto partecipati nel cap. 2. Molti di questi scienziati sono donne, e donne veramente in gamba: come l'etologa Jane Goodall e la virologa Beatrice Hahn, impegnate su fronti diversi per capire cosa è accaduto agli scimpanzé del Parco Nazionale di Gombe in Tanzania (cap. 8).
Altri "personaggi" sono più inquietanti: i pipistrelli, che praticamente svolazzano in tutto il libro e costituiscono i cosiddetti "serbatoi" per la permanenza di patogeni atti a infettare l'uomo. Sorprende apprendere che i pipistrelli costituiscono il 25% delle specie mammifere sul pianeta e che vivono in condizioni di affollamento che potrebbero ricordare quelle di molte metropoli umane... Sono quindi da tenere d'occhio, anche perché sono o sembrano essere le specie da cui i principali flagelli descritti nel libro, da Ebola a Marburg, dalla rabbia a Hendra, possono compiere lo spillover verso l'uomo. E dire che molte donne li temono perché, secondo una nota credenza popolare, potrebbero impigliarsi nei capelli costringendo le malcapitate a tagliarsi la chioma...
C'è molta scienza nel saggio e questo è uno dei suoi maggiori pregi. Quammen racconta con dovizia di particolari la genesi di alcune delle più note zoonosi, la lunga lotta per isolare i rispettivi agenti patogeni e le discussioni tra gli studiosi per analizzarne le caratteristiche. Le teorie dell'epidemiologia e della virologia sono presentate a partire da saggi e articoli scientifici, citati nelle note e raccolti poi nella lunga e dettagliata bibliografia (più di 25 pagine!): la disputa onda-particella sulla distribuzione geografica dell'Ebola (cap. 2) o il confronto tra virus a RNA e a DNA che porta al paradosso di Eigen (cap. 6), o ancora l'analisi statistica della virulenza che modifica in modo inquietante il vecchio assunto secondo il quale un patogeno non può uccidere in modo troppo efficace pena la propria estinzione come parassita (sempre nel cap. 6). Ho trovato particolarmente affascinanti i continui riferimenti alla matematica e alla statistica come discipline da integrare in modo profondo con l'epidemiologia e la citazione di alcune equazioni e modelli matematici di diffusione dei patogeni che hanno trovato piena conferma nella realtà.
Per quanto open-minded e aperto a tutte le testimonianze, Quammen sente il bisogno di fare giustizia di resoconti e libri sensazionalistici e inaffidabili come The Hot Zone: The Terrifying True Story of the Origins of the Ebola Virus di Richard Preston (1994)
e And the Band Played On: Politics, People, and the AIDS Epidemic di Randy Shilts (1987), con la consapevolezza che la diffusione del panico e l'invenzione di dettagli tanto macabri quanto fantasiosi non rendono mai un servizio alla scienza e alla società, come testimonia il pericoloso calo di vaccinazioni sperimentato nel nostro Paese da qualche anno a questa parte.
Il saggio di Quammen aiuta a risolvere molti dubbi e interrogativi: ad esempio, perché vaiolo e poliomielite siano stati debellati, mentre sia difficilissimo trovare un vaccino per certi tipi di influenza o per l'HIV, oppure perché la riduzione della biodiversità costituisca un pericolo diretto per l'essere umano (si leggano le pagine dedicate alle probabili cause della diffusione del morbo di Lyme nel cap. 5). Le due dimensioni dello spillover, la spinta ecologia e quella evolutiva, di cui parla l'ecologo Jon Epstein, sono le chiavi per capire se un patogeno avrà o meno successo. Altrettanto importante è non lasciarsi fuorviare dalla teleologia, a discapito della statistica, e attribuire ai patogeni una volontà "vendicatrice" nei confronti dell'essere umano.
Uno dei capitoli più belli è certo quello dedicato all'AIDS e all'HIV, scritto in forma di anello (e Quammen ne ha anche tratto materia per un breve saggio, intitolato The Chimp and the River: How AIDS Emerged from an African Forest): la ricostruzione dello spillover effettuato dal virus, dai primati all'uomo, è estremamente istruttiva e forse andrebbe riproposta nei corsi di scienze del liceo. Ricordo perfettamente l'emergere della malattia alla fine degli anni Ottanta, i dubbi legati ai meccanismi di diffusione e le numerose sciocchezze che all'epoca autorevoli esponenti politici propalavano alla popolazione senza preoccuparsi di impedire seriamente la diffusione del virus, magari suggerendo l'uso del preservativo nei rapporti occasionali o effettuando controlli sugli emoderivati infetti ("L'AIDS è una malattia che riguarda solo chi se la va a cercare", disse nel 1987 l'allora ministro della sanità, il DC Carlo Donat Cattin, alludendo a omosessuali e tossicodipendenti). Oggi ne sappiamo molto di più e perciò credo che le giovani generazioni che si apprestano a studiare medicina o biologia o biochimica potrebbero leggere con grande profitto il saggio di Quammen.
Con l'ultimo capitolo si conclude in Montana il lungo giro del mondo che abbiamo compiuto in compagnia di Quammen e dei cacciatori di virus, dalle giungle tropicali del Congo e del Cameron ai sofisticati laboratori dell'USAMRIID di Fort Detrick in Maryland, dalle fattorie dei Paesi Bassi agli affollati mercati del Sud-Est asiatico, dalle pianure desolate dell'Australia ai santuari buddhisti in Bangladesh. Il traguardo è nei parchi di una cittadina del Montana dove abita l'autore che, impotente come i suoi concittadini, assiste all'outbreak dei lepidotteri della specie Malacosoma disstria, voraci divoratori di pioppi. Vi lascio leggere la storia dei piccoli insetti e l'interpretazione proposta dall'ecologo matematico Greg Dwyer, che a me ha messo più di un brivido nella schiena. Quammen tuttavia conclude il libro con una nota di speranza, affidata all'intelligenza e alla versatilità di noi esseri umani, che a differenza di altre specie siamo in grado di compiere scelte ponderate.
Un altro punto di forza di questo brillante saggio è la traduzione scorrevolissima e di ottimo livello eseguita da Luigi Civalleri (di formazione fisico-matematico e docente del master in comunicazione scientifica della SISSA). Civalleri non si perita a lasciare nell'originale inglese termini del lessico specifico (fra cui quello che dà il titolo al libro), rendendo un ottimo servizio al lettore. Il volume è stato tradotto con il contributo del SEPS, un'associazione non-profit europea, con sede a Bologna, che si occupa di favorire la traduzione di saggi scientifici da una lingua all'altra.
Unico piccolo neo: oltre alle cartine geografiche, sarebbe stato auspicabile inserire qualche immagine dei patogeni e soprattutto alcuni grafici e diagrammi relativi alla diffusione delle corrispondenti malattie. Se il saggio è completamente scevro dai toni sensazionalistici e dall'allarmismo che contraddistingue l'informazione odierna, la raffinata Adelphi ha deciso di regalarci un piccolo brivido con la copertina di un funebre nero su cui campeggia un inquietante pipistrello dagli occhi rossastri che plana su di noi pronto a infettarci... un po' kitsch, ma molto efficace!
Consigliato agli aspiranti epidemiologi.
Sconsigliato ai chiroptofobici.
Il tema centrale – epidemie e pandemie che nel passato e nel presente hanno colpito gli esseri umani e quelle che potrebbero farlo nell'immediato futuro – è tra i più attuali e interessanti. Quammen mette in campo un buon numero di fonti per raccontarci la storia delle malattie infettive umane di originale animale, le cosiddette zoonosi: la cronaca o la ricostruzione giornalistica, le testimonianze delle vittime e le interviste agli specialisti, gli articoli e i saggi scientifici, e infine il racconto delle proprie esperienze al seguito dei "cacciatori di virus".
Una prova dell'abilità mostrata da Quammen nel costruire questo saggio si ha subito nel primo capitolo, che funge anche da prologo, in cui si narra della comparsa, nel settembre 2004, di un nuovo, misterioso, virus che attaccò e uccise numerosi cavalli prima di colpire alcuni esseri umani. La vicenda del virus Hendra - dal nome del sobborgo di Brisbane, nello stato australiano del Queensland, teatro della storia - viene assunta a case-study e fornisce a Quammen lo spunto per fornire le prime informazioni e mostrare al lettore come gli scienziati procedono per identificare le cause di una malattia e gli agenti (virali o batterici) che ne sono responsabili. Proprio nel primo capitolo vengono definiti i tre concetti chiave dell'intero saggio: zoonosi, malattia emergente e spillover, il salto di specie che l'agente patogeno può fare quando si verificano certe condizioni ideali (per lui, meno per chi ne viene colpito). Quammen sottolinea più volte che sono zoonosi quasi tutte le epidemie e pandemie che hanno colpito gli esseri umani nel corso dei secoli, in particolare negli ultimi 150 anni: tutti i tipi di influenza (compresa la famigerata spagnola, che tra il 1918 e il 1920 si stima abbia ucciso circa 50 milioni di individui in tutto il globo), la SARS, l'AIDS, la peste bubbonica, la rabbia, la malaria, il morbo di Lyme, l'antrace, le malattie causate dai virus Ebola, Marburg, Nipah etc. L'elenco è lunghissimo, e ci rammenta due cose importanti, dice Quammen: la prima è che l'uomo è un animale che al pari di cavalli, maiali e scimmie può essere infettato dagli stessi patogeni, opportunamenti mutati; la seconda è che il Next Big One, la prossima malattia emergente che diventerà per l'Homo Sapiens una pandemia, potrebbe essere con ogni probabilità una zoonosi.
Credo che non si possa esagerare l'importanza delle riflessioni sulla stretta correlazione tra le zoonosi emergenti potenzialmente distruttive e l'impatto di Homo sapiens sul resto della biosfera (dal consumo del suolo alla disintegrazione degli ecosistemi, dall'inquinamento al riscaldamento globale, dallo sfruttamento indiscriminato delle risorse naturali alla sovrappopolazione). Secondo molti studiosi intervistati da Quammen, ci stiamo in un certo senso scavando la fossa da soli: sterminando le specie selvatiche, sostituendole con quelle addomesticate e aumentando noi stessi di numero, stiamo fornendo a virus e batteri un nuovo terreno di caccia, in cui le prede siamo noi stessi. Molto illuminante, a questo proposito, è il racconto delle abitudini culinarie dei cinesi meridionali, avidissimi di cibi esotici preparati con creature selvatiche nel cap. 4.
La curiosità del lettore viene adeguatamente stimolata dai racconti delle spedizioni dei cacciatori di virus alle quali Quammen partecipa come testimone, e spesso come collaboratore: i tortuosi itinerari congolesi del team del biologo Mike Fay sulle tracce di Ebola e dei gorilla scomparsi (cap. 2); la caccia ai pipistrelli ferro di cavallo a Guilin, vicino Canton, al seguito del biologo Aleksei Chmura per scoprire di più sul virus della SARS (cap. 4); la cattura di macachi nel Santuario delle Scimmie di Sylhet, in Bangladesh, al seguito della squadra dei coniugi Jones-Engel alla ricerca dell'herpes B, patogeno che sembra colpire quasi esclusivamente ricercatori in virologia (cap. 6), etc. Nonostante i pericoli, che non provengono soltanto dai virus, ma anche dagli animali stessi (provate voi a imprigionare una decina di scimmie furibonde), Quammen ci dà un quadro molto realistico di cosa significa occuparsi di epidemiologia, immunologia e virologia, comunicandoci anche qualche particolare piuttosto curioso, come il fatto che i pipistrelli se ne stiano tranquilli appesi dentro a un sacchetto di tela. I cacciatori di virus costituiscono in realtà un gruppo molto eterogeneo: oltre ai biologi, agli etologi e agli zoologi che lavorano sul campo con gli animali, ci sono i medici e gli infermieri che curano gli ammalati, i ricercatori che isolano i patogeni in laboratorio e gli analisti che li studiano tra teoria ed esperimento. Quammen è molto attento a restituirci, nelle numerose interviste incluse nel saggio, il lato umano di tutti questi scienziati, impegnati in prima linea contro minacce microscopiche ma letali.
Tra i "personaggi" di questo libro che mi hanno colpito di più il già citato Mike Fay, instancabile ricercatore che attraversa a piedi la giungla del Congo dividendo il suo lavoro tra raccolta dei campioni ed assistenza alle vittime dell'Ebola (cap. 2), Aleksei Chmura con cui Quammen ha un'interessante discussione sui limiti gastronomici della nostra specie (cap. 4), gli ingegnosi coniugi Cox-Singh che si sono inventati un nuovo modo per catturare il DNA in assenza di apparecchiature sofisticate (cap. 3), la coraggiosa infettivologa Brenda Ang, tra i primi a fronteggiare l'epidemia di SARS tra il 2002 e il 2003 (cap. 4), il virologo australiano e premio Nobel Frank Macfarlane Burnet, scopritore degli agenti infettivi della febbre Q e della psittacosi (cap. 5), Edward C. Holmes, il massimo esperto mondiale di virus a RNA (cap. 6), la ricercatrice Kelly Warfield, il cui incidente in laboratorio e la successiva quarantena è raccontato con accenti molto partecipati nel cap. 2. Molti di questi scienziati sono donne, e donne veramente in gamba: come l'etologa Jane Goodall e la virologa Beatrice Hahn, impegnate su fronti diversi per capire cosa è accaduto agli scimpanzé del Parco Nazionale di Gombe in Tanzania (cap. 8).
Altri "personaggi" sono più inquietanti: i pipistrelli, che praticamente svolazzano in tutto il libro e costituiscono i cosiddetti "serbatoi" per la permanenza di patogeni atti a infettare l'uomo. Sorprende apprendere che i pipistrelli costituiscono il 25% delle specie mammifere sul pianeta e che vivono in condizioni di affollamento che potrebbero ricordare quelle di molte metropoli umane... Sono quindi da tenere d'occhio, anche perché sono o sembrano essere le specie da cui i principali flagelli descritti nel libro, da Ebola a Marburg, dalla rabbia a Hendra, possono compiere lo spillover verso l'uomo. E dire che molte donne li temono perché, secondo una nota credenza popolare, potrebbero impigliarsi nei capelli costringendo le malcapitate a tagliarsi la chioma...
C'è molta scienza nel saggio e questo è uno dei suoi maggiori pregi. Quammen racconta con dovizia di particolari la genesi di alcune delle più note zoonosi, la lunga lotta per isolare i rispettivi agenti patogeni e le discussioni tra gli studiosi per analizzarne le caratteristiche. Le teorie dell'epidemiologia e della virologia sono presentate a partire da saggi e articoli scientifici, citati nelle note e raccolti poi nella lunga e dettagliata bibliografia (più di 25 pagine!): la disputa onda-particella sulla distribuzione geografica dell'Ebola (cap. 2) o il confronto tra virus a RNA e a DNA che porta al paradosso di Eigen (cap. 6), o ancora l'analisi statistica della virulenza che modifica in modo inquietante il vecchio assunto secondo il quale un patogeno non può uccidere in modo troppo efficace pena la propria estinzione come parassita (sempre nel cap. 6). Ho trovato particolarmente affascinanti i continui riferimenti alla matematica e alla statistica come discipline da integrare in modo profondo con l'epidemiologia e la citazione di alcune equazioni e modelli matematici di diffusione dei patogeni che hanno trovato piena conferma nella realtà.
Per quanto open-minded e aperto a tutte le testimonianze, Quammen sente il bisogno di fare giustizia di resoconti e libri sensazionalistici e inaffidabili come The Hot Zone: The Terrifying True Story of the Origins of the Ebola Virus di Richard Preston (1994)
e And the Band Played On: Politics, People, and the AIDS Epidemic di Randy Shilts (1987), con la consapevolezza che la diffusione del panico e l'invenzione di dettagli tanto macabri quanto fantasiosi non rendono mai un servizio alla scienza e alla società, come testimonia il pericoloso calo di vaccinazioni sperimentato nel nostro Paese da qualche anno a questa parte.
Il saggio di Quammen aiuta a risolvere molti dubbi e interrogativi: ad esempio, perché vaiolo e poliomielite siano stati debellati, mentre sia difficilissimo trovare un vaccino per certi tipi di influenza o per l'HIV, oppure perché la riduzione della biodiversità costituisca un pericolo diretto per l'essere umano (si leggano le pagine dedicate alle probabili cause della diffusione del morbo di Lyme nel cap. 5). Le due dimensioni dello spillover, la spinta ecologia e quella evolutiva, di cui parla l'ecologo Jon Epstein, sono le chiavi per capire se un patogeno avrà o meno successo. Altrettanto importante è non lasciarsi fuorviare dalla teleologia, a discapito della statistica, e attribuire ai patogeni una volontà "vendicatrice" nei confronti dell'essere umano.
Uno dei capitoli più belli è certo quello dedicato all'AIDS e all'HIV, scritto in forma di anello (e Quammen ne ha anche tratto materia per un breve saggio, intitolato The Chimp and the River: How AIDS Emerged from an African Forest): la ricostruzione dello spillover effettuato dal virus, dai primati all'uomo, è estremamente istruttiva e forse andrebbe riproposta nei corsi di scienze del liceo. Ricordo perfettamente l'emergere della malattia alla fine degli anni Ottanta, i dubbi legati ai meccanismi di diffusione e le numerose sciocchezze che all'epoca autorevoli esponenti politici propalavano alla popolazione senza preoccuparsi di impedire seriamente la diffusione del virus, magari suggerendo l'uso del preservativo nei rapporti occasionali o effettuando controlli sugli emoderivati infetti ("L'AIDS è una malattia che riguarda solo chi se la va a cercare", disse nel 1987 l'allora ministro della sanità, il DC Carlo Donat Cattin, alludendo a omosessuali e tossicodipendenti). Oggi ne sappiamo molto di più e perciò credo che le giovani generazioni che si apprestano a studiare medicina o biologia o biochimica potrebbero leggere con grande profitto il saggio di Quammen.
Con l'ultimo capitolo si conclude in Montana il lungo giro del mondo che abbiamo compiuto in compagnia di Quammen e dei cacciatori di virus, dalle giungle tropicali del Congo e del Cameron ai sofisticati laboratori dell'USAMRIID di Fort Detrick in Maryland, dalle fattorie dei Paesi Bassi agli affollati mercati del Sud-Est asiatico, dalle pianure desolate dell'Australia ai santuari buddhisti in Bangladesh. Il traguardo è nei parchi di una cittadina del Montana dove abita l'autore che, impotente come i suoi concittadini, assiste all'outbreak dei lepidotteri della specie Malacosoma disstria, voraci divoratori di pioppi. Vi lascio leggere la storia dei piccoli insetti e l'interpretazione proposta dall'ecologo matematico Greg Dwyer, che a me ha messo più di un brivido nella schiena. Quammen tuttavia conclude il libro con una nota di speranza, affidata all'intelligenza e alla versatilità di noi esseri umani, che a differenza di altre specie siamo in grado di compiere scelte ponderate.
Un altro punto di forza di questo brillante saggio è la traduzione scorrevolissima e di ottimo livello eseguita da Luigi Civalleri (di formazione fisico-matematico e docente del master in comunicazione scientifica della SISSA). Civalleri non si perita a lasciare nell'originale inglese termini del lessico specifico (fra cui quello che dà il titolo al libro), rendendo un ottimo servizio al lettore. Il volume è stato tradotto con il contributo del SEPS, un'associazione non-profit europea, con sede a Bologna, che si occupa di favorire la traduzione di saggi scientifici da una lingua all'altra.
Unico piccolo neo: oltre alle cartine geografiche, sarebbe stato auspicabile inserire qualche immagine dei patogeni e soprattutto alcuni grafici e diagrammi relativi alla diffusione delle corrispondenti malattie. Se il saggio è completamente scevro dai toni sensazionalistici e dall'allarmismo che contraddistingue l'informazione odierna, la raffinata Adelphi ha deciso di regalarci un piccolo brivido con la copertina di un funebre nero su cui campeggia un inquietante pipistrello dagli occhi rossastri che plana su di noi pronto a infettarci... un po' kitsch, ma molto efficace!
Consigliato agli aspiranti epidemiologi.
Sconsigliato ai chiroptofobici.
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