“Spillover: The Next Human Pandemic” – Hangout with Author David Quammen
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“Spillover: The Next Human Pandemic” – Hangout with Author David Quammen

September 16, 2019


Hi everybody. Welcome to Read Science in
conjunction with Scientific American. My name is Joanne Manaster
and I am a blogger with Scientific American and along with my
cohost Jeff Shaumeyer we like to take a little bit of time out
every once and a while to speak with a science author of either great books or
blogs or just something for TV, and today we are very fortunate to
have our guest David Quammen who is an author
and journalist who has written, well, I read fifteen books but I guess
twelve of them are non fiction. They include “Song of the Dodo”,
“The Reluctant Mr. Darwin”, and most recently “Spillover”
which is a work on science history and human impacts of emerging diseases, particularly the viral diseases. It has been recognized on seven
national and international awards lists and he has also published a few hundred
pieces of short non-fiction, featured articles, essays, and columns in all the places we are used
to seeing our great science writers which included Harper’s,
National Geographic, Outside, Esquire The Atlantic, Rolling Stone. He occasionally writes op-eds for the New York Times and reviews books for the New York Times
as well. He has been honored with
an Academy Award from the American Academy
of Arts and Letters. He is a three time recipient of
the National Magazine Award, he is a contributing writer
for National Geographic, and in whose service he travels often,
usually to wild and remote places. He is currently in
Bozeman, Montana right now. If you watch the
Weather Channel at all, you might be catching his video series based on the book “Spillover” called “The Virus Hunters” and its based on stories from the book so welcome David. (David) Thank you Joanne.
Very good to be with you. Hi Jeff, nice to be part of this (Jeff) Its a real pleasure
to be talking with you, David. I hope it doesn’t make you feel old
or something but I will say I was reading your books when I was three years old But I checked the list to make sure and I have read all of your books I’ve enjoyed all of your books I’m just starting “Spillover” so that’s my latest one to enjoy. I have a little story,
if Joanne reminds me later to tell about a personal connection But since we are going to be talking
some about this book, “Spillover”, and about the video
series on the Weather Channel which is called “The Virus Hunters”, I want to throw you the easy ball and say lets start by talking about
this idea of spillover what it is, what zoonatic is,
a new word for everyone to learn and why its important so
we have some context for these things we are going to discuss. (David) Yeah.
That is sort of the ABC’s of this whole subject The book is about zoonatic diseases very simply defined
as Zoonosis is an animal infection that is
transmissible to humans. That could mean a virus, or a bacterium, or a fungus, or preon, or a worm, or what else does that leave? A protozoan, a protist, all the things that infect
humans and other animals so zoonosis is an animal infection
transmissible to humans and if it causes symptoms,
if it causes problems, once that virus or whatever
it is is transmitted then we call that a zoonatic disease. Most of, I think the figure
is roughly 60 percent according to different accounts, of the infectious
diseases known among humans are zoonatic diseases
in the strict and sort of immediate sense, over the longer
term you could argue that all infectious diseases of
humans are ultimately zoonatic because we are a
relatively young species. And even our old diseases had to come from somewhere else originally. The book is all about the spillover,
hence the title, of infectous agents from non-human animals
into humans causing in some cases
dramatic disease, gruesome pandemics, and in the current years
seemingly causing an increasing drum beat of
new emerging diseases. (Jeff) You had a log, which
I hadn’t memorized, with all of the things that have been in the news lately like SARS and Ebola and HIV
and a much longer list than that, all of these are zoonatic. (David) That’s right, yeah. The influenzas are all zoonatic all of the influenzas emerge ultimately from wild aquatic birds there are things, little known things with names like nepovirus, and hendra virus disease, that come out of animals and get into humans and cause death on a small scale, but in very dramatic ways. You mentioned Ebola, SARS, MERS, out of Saudi Arabia, Middle Eastern Respiratory Syndrome Virus, is also a zoonosis. So virtually all of these
scary new diseases that we hear about, that we read about in the headlines, are zoonatic diseases because the fact that they are new, means they have come from somewhere else and gotten into humans, and
they turn out to be really destructive agents once they are in humans and in some cases not
just very destructive, but also very dangerously transmissible. (Joanne) Right so Ebola, of course,
is one that is really well known for being very transmissible and very
devastating but in short loops, it burns itself out, so do
you want to talk a little bit about that? (David) That’s right. Ebola has a strange reputation. It’s a very strange, dramatic,
gruesome disease, Ebola virus disease, but it’s not as preternatural, or quiet as gruesome, quiet as bloody as the public has been led to believe by some of the books that came out ten and twenty years ago. “The Hot Zone” was a riveting book when it came out about twenty years ago. I read it, a lot of other people read it, and in some cases it was the first thing that anyone learned about Ebola virus. I have been back and
forth a little bit with Richard Creston on this,
I don’t want to beat up on him.
But I think even he admits now that there was a bit of exageration a bit of I won’t call it poetic license but it was portrayed as
almost a preternatural virus that caused horrific bleeding in virtually every case,
people were bleeding out, people were melting down from this virus. Well, the experts have told me that’s really not the case with Ebola. It is a horrible disease. It kills between 60 and 90 percent of the people it infects, depending on the species of Ebola virus, depending on the circumstances, so it’s a terrible disease, but its not preternatural. It causes organ shut down, it causes something called disseminated intravascular coagulation which is a blood symptom that can in some cases lead to unusual bleeding but doesn’t necessarily in most cases. It causes a lot of vomitting and diarrhea and it causes people to die for those reasons, but its not very transmissible from human to human. As you said Joanne, it burns out. It burns so hot it kills
people so quickly, it makes them very sick so quickly, and kills them, if its going to,
so quickly that it doesn’t spread as well as some others. Also its not an airborne virus its not transmissible on a sneeze or a cough the way the influenzas and some of the coronaviruses are. So Ebola virus is the most infamous of all these things and its a terrible disease
if you are an African villager but its not the highest on the list of global threats. (Joanne) So what would be
highest on the list of global threats? I’m going to guess its a flu, but.. (David) Well flu, a flu
would be in that group. Near the end of my
research for “Spillover” I asked some of the experts that I’d
been talking to over the years What do you think the next big one will look like? What should we be watching for? and they said well, there will be a next big one its inevitable that there will be another large pandemic whether it kills tens of thousands,
hundreds of thousands or millions of people,
depends on circumstances and how we respond, but,
something like that will come along. It will almost
certainly be a zoonatic agent. It will come out of non-human
animals. It will almost certainly be a virus, it will probably be a
single stranded RNA virus because they replicate less reliably, they mutate, they have
a high rate of mutations so they are very changeable,
the single stranded RNA viruses very changeable and
therefore very adaptable and then you look down
that list of single stranded RNA viruses of zoonotic
origin and the experts say well, that brings us to the influenzas, the coronaviruses, the
paramyxoviruses, so things like SARS represent good scary paradigms for what the next big one might
look like. SARS or the influenzas or some other
sort of coronavirus and that’s the reason people have
taken MERS so seriously, this new virus out of the Saudi Arabia, because it falls in that small
group that rank highest on the watch list of possible
next really, big, bad ones. (Joanne) types of viruses so has,
now of course comment sections are really hard to gather, but has the
middle east been dealing with this appropriately? Because now we do
have our first case, someone who traveled to Saudi Arabia has ended up in Indiana
then diagnosed with MERS my understanding is that at this point human transmission is low, and they are
seeing a lot of the cases might come from camel milk or camel meat and otherwise
implicating camels but maybe bats seem to be a new reservoir,
but yeah you could expand a little bit on MERS in the middle east? (David) Right, well, as of this
morning a message that I got yesterday MERS now stands at 411 cases
with 112 deaths. So that’s a case fatality rate. (Joanne) of like 35% or so? (David) I think its about 27%. So
that’s high but it’s not anywhere near as high as Ebola. Its higher
actually though than SARS was SARS’ case fatality rate was around
10% if I recall correctly something like 8,000 people infected
around the world with 800 fatalities so this has got a higher case
fatality rate than SARS but its not nearly as transmissible
human to human as SARS I gather there does seem to be some,
at least suspected, human to human transmission. I think as of the report
yesterday, I think there were 15 new cases and of the 15
new cases, seven of those were among contacts, personal contacts
of people who had already been confirmed as having MERS.
(Joanne) Like hospital workers or family. (David) yeah, so the
secondary cases, seemingly secondary cases, but I don’t think
that has been proven that they are secondary cases because
there is always a possibility that these secondary cases could have
shared situations with the primary case and they might have been
exposed directly to the reservoir host, or the amplifier host of the
virus rather than getting it from humans. So I’m tossing these terms around,
reservoir host and amplifier host. The reservoir host is the species of
creature, or maybe in some cases several species of creatures, in which
the virus or the other pathogen lives endemically, permanently, inconspicuously,
without causing symptoms. That’s its permanent residence. If it is
something that kills humans as soon as it gets into us then it has to live
somewhere else over the longer term to survive.
That’s the reservoir host. An amplifier host is an animal or a
species of animal that serves as an intermediator, in the case of, for
instance, Hendra virus in Australia, it is known that the virus resides in fruit
bats, three species of fruit bats, it spills out of fruit bats, and gets
into horses, and then it really rampages through horses it causes horrible
symptoms, fast death, high viral loads, a lot of viral shedding in horses and then
it gets into the people who take care of horses, veterinarians and horse trainers
and people. That’s been the pattern of the Hendra virus. Now, with MERS in
Saudi Arabia, I think there is some suspicion that the virus might have it’s
reservoir host in bats, but that it has a presence in camels, as an amplifier
host, and that humans are perhaps getting it from camels and not directly from
bats. But the camels may be getting it from bats, but there
is new work that’s just been published in about the last week, online by a group of who the senior
author is Ian Lipkin at the Mailman School of Public Health at
Colombia, who is a brilliant laboratory researcher on these emerging
viruses, and Ian Lipkin and his group, if I recall correctly, found that based
on molecular phylogenetics, this virus has been circulating in camels since
about 1992, there is enough divergence among the
different strains found in camels in Saudi Arabia, possibly
also Egypt, to suggest that its not just spilling over day by day from bats into
camels, and then from camels into people but it’s perhaps circulating as a new
infection, but as an infection that has become endemic in camels. As I say, don’t hold me to every detail
of what I’ve just said, but that’s what I recall seeing in this new report that
I just saw online, a few days ago. (Joanne) So this brings a couple
questions, one is from someone who is asking
a question here from our audience they said, “Many of zoonatic diseases
examined in “Spillover” need bats as reservoir hosts.
What impact does bat habitat destruction have in this
puzzle? And that is one thing if you read the book, you will leave going,
I think I should be afraid of bats. (laughing). (David) Well, I hope I didn’t add
to the undeserved bad reputation that bats have, they have enough PR
problems. And I did not want to demonize bats.
I wanted to describe the situations. (Joanne) I thought it was
realistic though, I didn’t feel like there was any overt, attempt at demonization. But
they just kept coming up again and again. (David) But yes, there is a
strong pattern that in many many cases these
new zoonatic diseases have been found to have their reservoir
host in one species or other of bats. So that scientists
started asking: Why bats? Why do they seem to be disproportionally
implicated as reservoir hosts? And there are a couple of possible
explanations for that. One is that bats are a very
very diverse group of animals There are lots of species
of bat, I think it’s one of every four species of mammal
on planet Earth is a species of bat, so they are disproportionally represented
in the diversity of mammal species. Also, many of them live long life
times they live to be 18 or 20 years old. They’re very social, they live in huge
aggregations. So you put those things together,
long life spans and massive colonies, at very very close proximity to one
another and you have potentially very good circumstances for incubating
viruses, for allowing viruses to live and persist in a population of
animals. (Jeff) And they travel widely too right? (David) and they travel widely.
They move around, and not just in two dimensions, but in three dimensions
they occupy a big volume of space so all of those things combine to create
this pattern wherein a large number of these new diseases are found to have
their reservoir hosts in bats and SARS which is a coronavirus, belongs
to the coronavirus family, was found in several species of bat
in southern China, and because of that bats were high on the list of
hypothetical reservoirs for MERS because it also is a coronavirus not
too closely related to SARS but within the same family anyway. So some of the
people I write about in my book were involved in doing field work in Saudi
Arabia. Testing bats, sampling bats, looking for evidence of
this new MERS coronavirus and they found some. They found that
there was evidence of the virus in bats but they didn’t find such a prevalence
in bats, and such a high level of virus as to answer the question definitively
where this virus has its reservoir host but the original question was about
habitat destruction. Let me loop back to that before I chatter on too much more
about bats. The question was absolutely right that habitat destruction causes
bats to move closer to humans at least in some cases, this is true in
Australia, where the great inland eucalyptus forests have in broad
areas been cut down, been chained down, been clear cut for agriculture and
human development of various different sorts, and those eucalyptus forests
were habitat for some of the fruit bats that carry Hendra virus, among others
and those fruit bats are now coming into the city. To Sydney, to the botanical
gardens, to the parks in Sydney. They’re coming into orchards along the
eastern coast of Australia up in the sub tropical Australia. They’re coming
closer to humans. And that may be the reason that suddenly this new virus
known as Hendra, started getting into horses and then humans back in
1994. In Malaysia, likewise, the destruction of Malaysian
tropical forests seems to have pushed some species
of bats closer to human orchards
places where humans are growing fruit trees, on which the bats
can feed. These are big tropical fruit eating bats
that they actually eat fruit, and in some cases blossoms and nectar. So they go looking for those
things and if people have planted
orchards, then those will attract bats, when the bats are driven
out of their natural habitat and if the orchards happen
to be planted on pig farms, around pigsties, around even
overhanging pigsties, as was the case in northern
Malaysia then that represents a great opportunity
for the virus to spill over down from these bats down
into the pig pens getting into the pigs, this
happened with nepovirus causing an outbreak of this
disease in pigs and then it passed from pigs
into pig farmers, pig butchers pork handlers, and ended up
killing more than 100 people in the pork industry in
Malaysia. (Jeff) Well habitat destruction
is a big part of your answer to the question of why do we think
we’ve seen so many of these zoonatic outbreaks in the last
few decades? Is that a real phenomenon? Or are we imagining it
and it seems that it’s real and that there are several reasons and that
is one of them? (David) Absolutely yes. Yeah,
habitat destruction. The fact that we are pushing
into the highly diverse ecosystems where lots of
different kinds of species, including lots of different
kinds of viruses, live. We’re building roads, and
timber camps, and mines, and settlements
in the central African forests, in the forests of southeast Asia,
in the forests of South America, and we’re disrupting ecosystems,
we’re destroying habitat, we’re killing and eating the
native animals, and in some cases we’re capturing them and
shipping them to live animal markets in other countries. We’re doing all these
sorts of things that are disruptive of native species, and that bring
us into close contact with native species both animal and
plant, but I think we’re talking mostly about animals, and those
animals, those different kinds of animals carry different kinds of
viruses. So we offer opportunity to those viruses, to change hosts,
to spill over, to leap from one species of animal into this other species,
that happens to be humans. And that turns out
to be, as I said in the book it turns out to be a great
career move, if you are a virus and you infect some sort of
endangered species of primate in central Africa, and you manage to
jump from that endangered species of primate into this other kind
of primate, of which it turns out there are 7 billion individuals
all moving around the planet closely interacting with one another,
then you’ve just made a great career move. And that is what
the HIV-1 virus did. (Jeff) Right. If Joanne
will let me there is some lurking science communication issues
I wanted to… (Joanne interrupts) Although quickly,
since he ended with AIDS, you do, it looks like your last
chapter of your book is going to be turned into its own standalone
book, right? We want to make sure our watchers
here are aware of that. (David) Thank you Joanne, yeah.
Actually the second last chapter of my book, I think of it as the crescendo
of “Spillover”, its a long, about 100 – 110 page chapter on the
ecological origins of the AIDS pandemic. How a chimpanzee
virus, spilled over from a single chimp into a single human,
back around 1908, give or take a margin of error, in the southeastern
corner of Cameroon, we know all this now from good molecular work, and spread across the world as
what we now know as the AIDS pandemic. So I tell the story
of these new scientific findings worked on by some wonderful
scientists Michael Worobey in Tuscon,
Beatrice Hahn of University of Pennsylvania and
a lot of their colleagues that have developed this new
and radically unexpected story of the origins of AIDS.
so I tell that whole story in my penultimate chapter, which
is titled “The Chimp and the River” and my publisher WW Norton
has decided that they want to in addition of publishing a paperback
version of “Spillover” in the coming, I think this winter, they will publish
“The Chimp and the River” as a small free standing paperback book
itself with a new introduction by me. (Joanne) I actually
think that’s a great move because some people will be
intimidated by a book of this size so I think just having the AIDS, and so
many people have questions about AIDS (David) Well good, well I hope
you are right. We think that makes sense too. Now it is, “Spillover” is a
long book, I like to think of it as a concise long book. (Joanne) It is, it’s excellent. (David) The AIDS story
is very important, and very counter-intuitive, very different
from what most people think they know about the history of AIDS
so it seemed like a good idea to put it out as a free standing book. (Joanne) We’ll be sure to promote it. (David) (laughs) Yeah. (Jeff) So there are lots of
things we were talking about Ebola, and how it may have been
over sensationalized and there are several issues, I think about how to
get precise and accurate information to people who need to know about it
and may be not interested and I thought, one starting place I was thinking about
when I was reading the first chapter about Hendra virus and how it had moved to
some humans through horses and that whole thing, and you were
talking to a racehorse trainer, I pictured it in a bar or something,
and a little bit of what he had to say, he gives you his perspective on the
Hendra virus. He said, “They shouldn’t allow it! They should
get rid of those bats! Because of the disease. They hang upside down
and they shit on themselves, and then they shit on people! It’s backwards
let the people shit on them! Yeah but those sentimental greenies
won’t allow it!” and I thought boy, but there is so
much mixed up in his head but how do you break through?
There are several ways to push this but how do you break through those
attitudes? How do you get in there? How do you do some instruction?
Some useful learning and understanding without
being sensational or, everyone has to make
a choice. I think that one choice is sort of to be
calm and very thorough and some people will see it and
you can use materials and that is sort of the way
I’m thinking of spillover and your long conciseness, and you
always approach things with a thoroughness, that’s not boring but
is very important to have and I think that is one way to keep
people calm at least the ones who hear the message
and not everyone is going to hear a message. Is that a choice? How do you decide
these things, how do you avoid sensationalism? Or should you? (David) Well yes, I think
you should. This is potentially a very
sensational subject, maybe even objectively you
could say it is. A lot of people die in this book.
There is a lot of gruesome misery. And its important
I think to convey that, because these viruses many of them are
very very dangerous and the subject is important. So it’s dramatic,
and I wanted to make it dramatic so that people would pay
attention. But I did not want to make it melodramatic.
I did not want to exaggerate. You don’t need to exaggerate
these things in order for them to be arrestingly scary. So I stayed very close, tried
to stay very close to accurate and precise scientific information as it
was presented in the journal literature. When I write a book I travel a lot, I talk to a lot of scientists, I try to spend time in the field,
with field scientists, and I also read huge piles
of journal articles, I read a lot of journal articles, and so that’s where some
of the information, a lot of the information, comes
from, the hard facts. And if they have
appeared in peer reviewed journal articles then you can
presumably rely on them. So that’s where I get a lot of my
hard facts about, for instance Hendra virus or Ebola virus. When I report from the field
I hold myself to a very strict standard of accuracy. In terms, for instance, of
quotes, if I don’t get a quote verbatim in my notebook,
either because I’m scribbling fast, or
on my recorder because I’m taping then I don’t assemble my best
recollection of what somebody said and then put it in
quotation marks later on. For instance you mentioned that
racehorse trainer we were in a bar, we were at
a race course we were in the member’s lounge of a race course
in Australia and I had been brought in my
veterinarian friend who dealt with this disease. A wonderful fellow
named Peter Reid. So he took me to the races
one day , and took me into the member’s lounge and I met
the owners and trainers along the stables and in the back. So I was behind the scenes,
and I was his guest and he introduced me to this
famous Australian race trainer who had won all the big races
in Australia. His name was Bart Cummings, and
he was quite a character. But we were standing there
with beers in our hands and he hears that I am a writer,
following the threat of the story of Hendra virus. And he starts to
give me an earful saying like “Oh they should kill all
the bats etc etc” Well, I’m certainly not
taping him, and I’m really not in a situation to be scribbling
in my notebook, it would seem peculiar and rude. I think I did
scribble a few notes but I did not get his
tirade verbatim and if you look back at that
passage in the book, unless I am hugely mistaken,
there are no quotation marks around what he said, I am
essentially paraphrasing him. Maybe I put it in italics
or I did something to indicate this is the essence of what this guy
said but I’m not claiming that this a verbatim quote. (Jeff) Oh sure. Sure. Well it
certainly gave the flavor of the communication issues
some people might try to directly go at some of his
misconceptions. There’s an awful lot, it’s like,
he’s got some of the truth in there. We learned about the bats and things.
He knows bats are involved but it’s because he has come up with this
idea that bats hang upside down so they shit on themselves
then somehow that causes the disease (coughing)
What do you do? And I think what you do, which
I quite like, is not try to take all of those misconceptions apart
but to tell the coherent story sort of calmly from the
beginning, and try not to be distracted by that. (David) Well good, that’s
what I try to do and I’m glad that it seems like a good
tactic to you, Jeff. I mean there are a couple
of places where it would have been possible to just stop and
give readers a lecture on how important bats are and
they’re beneficial to our ecosystems and they
deserve to live, and you shouldn’t demonize them,
and they pollinate plants, and they eat a lot of insects,
and things, and I mean, I have written a lot of that
kind of thing in other books and in other places, and it just
seemed to me maybe I’m mistaken in this, but
it just seemed to be so obvious, those things. That to
a reasonably intelligent reader that I didn’t want to bring the
narrative and the science explanation to a halt in order to
give that particular ecological lecture so I didn’t, and essentially I let
the facts speak for themselves. (Jeff) I would say it’s a good
choice, not to everyone, but not to entirely change the subject,
but what you can do, in telling those stories in 500 pages of “Spillover”
is an awful lot different from what you could do in a 5 minute
video on the Weather Channel right? And we have both
of these and they are very different ways
of telling the stories. And I think the book appeals
to me more, but I can see a lot of value in the videos,
but do you have anything you want to say about what
you give up by having to work within those 5 minute videos? (David) Yes, I mean this series of videos “Virus Hunters”
is now up on weather.com, produced
by some very good filmmakers at the Weather Channel,
and they came to me, I guess last fall,
through my agent and said “We would like to make a series
of short films, about what you write about in the book,
about some of the facts and ideas and characters of “Spillover”.” And they said, “When we say
short films, we mean short. This is what is happening now
with media, very short but well produced, dramatic
films for streaming on the web. 4, 5, 6 minutes long.
We want to do 6 of these episodes.” So I saw
some of their other work and it was good, it was responsible, it was careful
and it was also dramatic and effective. I saw a couple
of episodes they made about conservation biologists and field
biologists that I know and I thought they did a very
good job of capturing some important things in that little cameo form,
so I said yes, let’s do this. And I was involved with them
in terms of developing contacts, and helping them with ideas and ground truthing some
of their early versions, and helping them
correct things that needed to be corrected. And I
think I’m listed as an executive producer in that basis. But I
didn’t write the scripts. They wrote the scripts.
I helped correct those, so yes you give up a lot
to reach a particular, different kind of audience
in a different way. If I were to start from
scratch and say, “Well, I want to produce a
television series based on “Spillover””, I would
not say, “I want each episode to be 6 minutes long.”
(sounds of agreement) but that was an
opportunity of a particular sort presented to me so I said,
“Well, let’s explore this and see if we can do it
in a way that’s useful, and doesn’t trivialize these
diseases, or these people, or these topics, and if we
can do that, then I’m happy to proceed.” They showed me that they
could do that. You give up an awful lot, but little slices
that you get, I think have a particular value in the form
that they’re in. (Joanne) Right, well I
thought that they were fantastic. Would it be okay if we
go to some of our viewer questions? (David) Absolutely. Yeah. (Joanne) Okay, well we’ve
got one here saying, “Do you think vaccinating primates against
diseases like Ebola could help prevent outbreaks?” (David) Well, vaccinating
wild animals is always tough. It’s just difficult logistically.
But it’s not a crazy idea. It has been considered and
work has been done towards developing a vaccine against
Ebola that could somehow be given to gorillas and chimps in
central Africa because, we haven’t talked about this
but it’s in the book, Ebola turns out to be devastating
not just to humans but also to gorillas and chimps and there
are some people who believe Ebola has been spreading
through gorilla populations in central Africa, killing thousands or
tens of thousands of gorillas over recent decades. There are areas of wonderful
gorilla habitat in central Africa, for instance in Gabon,
that these areas of wonderful gorilla habitat that are empty
of gorillas. And I walked through
one of those areas for ten days on a National Geographic
assignment some years ago with a fellow who was censusing
wildlife, looking for gorillas among other things and in ten days of walking
we found sign of, hundreds and hundreds of signs of forest
elephant and other creatures that were alive and well in that forest
and zero sign of gorilla. What was the reason? Well, the probable reason was
that Ebola had killed those gorillas. Difficult to prove,
but strong inferential hypothesis. So, some of the wildlife conservation
people, including some very good veterinarians have been researching the
possibility of using some sort of baiting system, putting out food that
contains an Ebola vaccine to try and stop the spread, the chain of
transmission of this disease in gorilla populations and the
devastation that it causes. So, as I say, it’s difficult to do,
difficult to vaccinate wild animals. How do you get to every one of them?
How do you get to enough of them? You don’t go running through the forest
tranquilizing gorillas and giving them injections, you have to
do something that is more effective than that, so people are thinking about it
people are working on it. (Joanne) That’s actually a
really good answer, so here’s something that’s interesting.
This comes to probably humans affecting our environment, this
is actually about global warming, which there are whole books written
about how global warming is affecting our health, but this one is
interesting. “With global warming being all too evident, and the
glaciers and ice caps melting, what is the probability that
an ancient virus or bacteria that has been frozen, thawing out
and being re-introduced into the world?” This is not exactly Zoonosis but,
you have become an accidental expert by writing a book. (David). Yeah. Right. Well a
virus frozen in glaciers? Well, viruses only survive in living
cells. So if an animal is frozen for ten thousand years, is it
possible for a virus in that animal to be reactivated?
I suppose that it is. And if I’m wrong I’m sure
people will correct me immediately on that one
but thats my ‘off the top of my head’ recollection response. It might be possible. (Joanne) Yeah I’d not
heard this before so… (David) Yeah, well
you know we know that you can get ancient DNA out of
a creature, even a human being, that’s been frozen for ten
thousand years. It might be possible to wake
up a virus that’s frozen in cells of such creature. Whether that’s something
worth worrying about is a different question. I mean there are a lot of reasons
to be concerned about climate change, global warming, I wouldn’t put
that near the top of the list, because there are so many
other viruses that aren’t frozen that we are coming in contact with. Some people estimate that
every species of plant, animal, fungus, bacterium, on the planet
probably is a unique host of at least one virus, maybe ten viruses,
these are very very rough ballpark guesses. So that you don’t need
to go to a mammoth thawing out of the ice in northern
Canada that might be carrying a new virus in order to
be exposed to a new virus. All you have to do is walk across
central Africa and turn over a couple of rocks, and
eat a fish, and touch a turtle, and be shat upon by a bat,
to be exposed to new viruses. (Joanne) Right, or eat the fruit that
the bat has shat upon. (David) Yeah, or pick up
a piece of fruit that a bat has licked. (Jeff) Well our mothers
were right when “Don’t touch that turtle! You’ll
never know where it’s been!” (David) (laughs) That’s right. (Joanne) Well, and infectors like
mosquitoes, their habitat is increasing with warmer climates
so that infector born disease is not necessarily zoonotic but you did
address that as far as Malaria like how it may have originated in
a different animal. It didn’t just evolve. (David) Yeah.
That’s what I think of when I think of the potential impacts of
climate change in terms of infectious disease in general, and
zoonotic disease in particular. I mean, now we’ve got,
don’t we have West Nile fever in all of the 48 contiguous states?
I think we do, and what’s the reason for that?
Well, one of the reasons for that is there are mosquitoes that are infectors
for West Nile virus that are surviving through the winters in places
where they did not use to survive through the winters. (Joanne) Right.
Yeah, it’s amazing. There is one more question here
from our readers. This one you can modify to answer
the way that you see fit He is asking, “What are the top two
mistakes that humanity has made by in large, historically speaking,
when it’s been hit by a pandemic?” So I suppose you could answer
just one. (David) I remember.
This is from Hugo right? (Joanne) Yes. (David) Interesting question, Hugo. Well, the mistakes that we make
have changed over time. For instance, in the late 19th
century in America, when people came down with
smallpox, we would put them in pest houses. And in particular if they
were poor, and came from tenements and slums. We would
drag them out of those tenements and slums, officials would, city or
state officials, and would confine those people
in pest houses, and these pest houses then
became wonderful places of transmission if you were
a suspected case, but not confirmed and you were confined in a pest house,
the chances are that you would become a confirmed case very quickly. That sort of response,
the idea that infectious diseases were endemic to
poor people, was a horrible mistake,
but it was a common mistake. The idea that poor people,
because their hygiene standards were not high enough, they
were particularly susceptible to these diseases and therefore the
way to deal with these diseases was some sort of a
public health apartheid. That was a horrible mistake
that was made with severe consequences in this
country and a number of other places. In terms of mistakes
that we are making now, Well one potential mistake
is related to that, it’s the notion that
the way to deal with these diseases is to confine people,
to shut down movement, to treat the disease
as a form of guilt. You know we saw that
in the early stages of the AIDS pandemic in the US,
that also occured in Cuba, where people who were HIV
positive were, well I don’t want to say more than I
actually know, but I think in Cuba there were
some harsh measures towards people that were
HIV positive, in terms of segregating them
from the general population. With Ebola, currently
there’s this outbreak in Guinea and they are trying to stop it,
but I noticed that the world health organization has
not recommended restrictions on travel. Guinea. Why
is that? Well, the way it’s been
explained is that if they invoke restrictions on travel and
force confinement of possible cases, you’re going to drive the disease
underground, and people are going to be afraid to
go to clinics if they think they might have the disease
because they’ll be treated as guilty. They’ll be treated as
prisoners. So generally, I guess what I’m saying is,
one of the worst mistakes that we’ve made is the
confusion of being infected with being guilty of something,
and the forms of social segregation and constraint
that followed after that, and we’ve mostly gotten past
that but its something we’ve got to be very careful about. (Jeff) This was something that
we sort of talked about, but I made a note of this. As you were talking
about how these outbreaks of these various zoonotic incidents might
be seen as independent, disconnected, perhaps judgmental
things, said to point out the varoius groups of people as causing
this or that and in fact they are
related, there is a pattern, there are things we can understand,
and it’s a natural event, and it can be pretty hard to keep
our prejudices even for scientists out of understanding what’s going
on, right? (David) That’s right.
We can demonize the victims, we can demonize the reservoir hosts,
we can demonize anybody associated with these things, and that does not lead us either to better understanding
or to better response to these things. I think the way I put it in
the book is that there is a tendency
for the public to think that this drumbeat of new diseases,
Ebola, and Machupo, and Hendra and Nepo, and SARS, and Bird Flu
and MERS, and a number of others, that this drumbeat of
diseases represent things that are happening to us. Independent
forms of misfortune that are happening to us, and the point that I try
to bring out in the book is that these are not merely things that
are happening to us, these are reflections of things
that we are doing, they are part of an
interconnected pattern that relates to our activities,
how we live together, and how we live with other species
on this planet. (Jeff) Yeah, and that things are
different when that’s the habitat destruction, and how we can
do all of these things when there are only say,
500 million people on the earth versus when there are 7
billion people on the earth. (David) That’s right, some of
this the scientists would call this density dependent effects. The fact that if somebody gets
sick from eating a wild animal at a restaurant in southern China,
and that person picks up a virus and that person goes to a wedding
in Hong Kong, and stays in a hotel and coughs or
sneezes in the elevator, and some woman from Toronto can
walk into that elevator, pick up that virus, and
that virus will travel around the world in about 14 hours. That’s a new situation. (Joanne) That’s sort of the
plot for Contagion. So I’m looking like we are at
the end of our show, and its been wonderful to talk
with you David and I really hope our audience here,
if you have not picked up “Spillover” and you’re up
for a nice book. Its got technical depth,
its an engaging story, because you have personalities,
its not just a review paper on every type of zoonotic disease.
It’s really an engaging story. (David) It’s full of detective
stories, I like to say. (Joanne) Yeah, it is like
a detective story. This is great, which makes
the 500 pages go by fast. It is one of the ones
that is hard to put down, which is always helpful
when it’s a big book. And I really enjoyed it.
I also listened to it on audio, I would switch
back between book and audio, and you had a great narrator
for this too. So, is there anything
else you would like to add that maybe we forgot to ask you,
David, before we sign off? (David) Be safe. Travel well.
Stay healthy. And don’t eat the monkeys. (Joanne) Don’t eat the (laughing)
Yes. we have one last story Jeff has a website called
Scienticity and his website has a mascot. And it’s related
to you, David. (Jeff) Yep. The Scienticity
mascot is an American crow and the reason that we thought
the crow was an entirely suitable animal was largely based on,
or largely inspired, by your article from long long ago called something like, “Are
Crows a Product of their own Success?” or “Has Success Spoiled the Crow?”
-(David) Yeah, “Has Success Spoiled the Crow?” I remember that.
-(Jeff) Yeah, in which you describe many of the antics and things they get up to.
Basically, you posited because they’re bored.
-(David) That’s right, yeah. (Jeff) I found very appealing that idea
that crows are just out to learn new things and have new experiences,
and I’ll say about “Spillover” that I enjoy reading it at that rate
and I think it proceeds in a way that parallels the way
science works and unfolds and that’s something that
I always look for as a mark of a good science book, so
congratulations on that. (David) Well thank you both very much.
It’s been a real pleasure to talk to you. I’ve enjoyed this and I
appreciate the interest in the book and the ideas. (Joanne) Great. Well thank you,
David, so much and thank you, Jeff, as always its a pleasure to
sit here with you, and thank you to everybody
who watched and turned in questions, and we will
see you again next time on Read Science.

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