"Spillover: The Next Human Pandemic" - Hangout with Author David Quammen

Hi everybody. Welcome to beats 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 awhile 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

I read fifteen books but I guess
twelve of them are non fiction

the include "Song of the DoDo"
"The Reluctant Mr. Darwin"

and most recently "Spillover"
which is a work on science history

and human impacts on 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

and 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
acadamy of arts and letters

he is a three time recipient of
the national magazine award

he is a contributing writer
for national geographic

and he travels often usually
to wild and remote places

he is currently in ??? Montana

right now if you watch the weather channel
at all and you might be

catching his video series
, based on the book "Spillover"

Called "The Virus Hunters"

and its base don stories from the book

so welcome David

(david speaking)
Thank you Joanne very good to be with you

Hi Jeff, nice to be part of this

(Jeff speaking) Its a real pleasure to be talking with you

and 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 is 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 speaking) Yeah.
That is sort of the ABC's of this

whole subject

The book is about zoonatic diseases

um, 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 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 around 60 percent according to

different accounts, of the infectious
diseases known among humans

are zoonatic disease
in the strict and sort of

imminence, in 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 of

infectious 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 speaking) You had a log which
I had 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 speaking) That's right yeah

these 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 a very dramatic way

you mentioned ebola, SARS, MERS

out of Saudi Arabia

Middle Eastern Respiratory Syndrome (MERS)

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

so in some cases no just very destructive

but also very dangerously transmissible

(Joanne speaking) Right so Ebola of
course is one that is real 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 speaking) that's right, Ebola

Ebola has a strange reputation

its a very strange dramatic, gruesome disease

Ebola virus disease

but its 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 a riveting book

when it came out 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 Cresten 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

is 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 its 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

kill them 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 speaking// So what would be highest

on the list of global threats? I'm going to guess

its a flu, but..

(David speaking) 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 yeras

what do you think the next

big one will look like?

what should we be watchign 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 zoanatic 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 thats the reason people have
take 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 speaking) types of viruses so has,
now of course common 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 and
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

you know bats seem to be a new reservoir,
but yeah you could expand a little bit on

MERS in the middle east?

(David speaking) Yeah 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 speaking) of like 35% or so?

(David speaking) I think its about 27%. So
that's high but its any where

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 infected around
the world with eight hundred 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 fifteen new cases and of the fifteen
new cases, seven of those

were among contacts, personal contacts
of people who had already been confirmed

as having MERS. (Joanne speaking) Like Hospital
workers or family

(David speaking) 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 has just been

published in about the last week, online.

By a group of who the senior
author is Ian Lipkin,

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 its perhaps circulating as 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 speaking) 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 and spill over

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 speaking) Well I hope I didn't
add to the undeserved bad reputation

that bats have, they have enough PR
problems. And I do not

want to demonize bats.
I wanted to describe the situation.

(Joanne speaking) I thought it was
realistic though,

I didn't feel like there was any

overt, attempt at demonetization. But
they just kept coming up again and again.

(David speaking) But yes, yeah 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
indicated 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 is one of

every four species of mammal on planet earth is a species of bat