David Quammen on Spillover

Q&A courtesy of W.W. Norton and Co., publisher of the book

So, Spillover is a book about hideous emerging diseases. Thanks very much. Where do these diseases emerge from?

They emerge from other species. They emerge from animals. They emerge from bats and rodents and monkeys and chimpanzees and…

What diseases are we talking about?

All the ones we love to hate and fear: Ebola, SARS, AIDS, Lyme disease, Marburg, West Nile virus, killer influenza, even one form of malaria, plus a long list of other nasty things you’ve never heard of.

Is this a new problem?

No. It’s an old problem. But it’s worse now than ever before.

Why worse?

Because we’re virtually forcing these viruses and other nasty bugs to come at us. We’re invading their territory. We’re cornering them. We’re cutting down the Congo forest. And when the trees go down, things fall out. We’re eating up the monkeys and chimpanzees and fruit bats and rodents that are the natural hosts of these viruses. We’re shipping bushmeat around the world. We’re riding airplanes ourselves, coughing and sneezing on one another. We’re offering ourselves, humans, as 7 billion gobs of alternative meat.

How did you get interested in this subject?

I was sitting at a campfire, in a Central African forest, in July 2000. Two Bantu guys started talking about the time, not long before, when Ebola hit their village. Friends died, family died. Ugly, horrendous. Around the same time, they saw a pile of 13 gorillas, lying dead, nearby in the forest. The gorillas had evidently died of Ebola too. That’s when it struck me: zoonotic diseases. Duh. Their diseases, our diseases: same diseases. Wildlife and humans. Gorillas and bats and monkeys and horses and civet cats and pigs and people. Lesson: We’re all in this together. We get sick together. We share diseases. Globalization means, among other things, the sharing of spooky new diseases.

What about AIDS? You say AIDS comes from wildlife?

The AIDS pandemic began, around 1908, when a chimpanzee virus passed into humans. It passed from one chimp into one human and the pandemic was launched.

I hate to ask but, how did the virus pass from a chimp to a human?

Not by sexual transmission, probably — if that’s what you’re thinking. It probably passed by hunting and butchering a chimpanzee. Blood-to-blood contact. The scientists call that the “cut hunter hypothesis.” One unlucky guy, a village hunter, killed and butchered a chimpanzee; he had a cut on his hand, maybe, and the virus got into him that way. The rest is disease history.

Where did this happen?

Very solid genetic evidence shows that it happened in southeastern Cameroon. That’s in the western part of Central Africa, north of the Congo River.

What about Ebola? Is Ebola the virus that’s going to leap out of Africa and kill millions?

Probably not. Ebola is a hideously lethal virus, but it doesn’t transmit all that readily. It’s horrible in African villages, when health care is inadequate, but it’s relatively easy to stop. It’s the charismatic microfauna - the disease people love to fear. But it’s not nearly as dangerous to the world at large as some others.


SARS out of China, Nipah virus out of Malaysia, influenza out of the ducks of Hong Kong, HIV and the things that may resemble HIV.

So the bottom line is we are all going to die?

Yes. We are all going to die. We are all going to pay taxes and we are all going die. But most of us will die of something more boring than Ebola or SARS or some other disease that spills over from chimpanzees or bats or ducks.

Then what’s the big deal with these zoonotic diseases?

The big deal is that many of us could die, in the next big outbreak of one of these newly emerging diseases. Not all of us but millions of people. Historians figure that 50 million people died of the 1918 influenza. Thirty million people have already died of AIDS. Influenza is still around. AIDS is still around. Both of those are zoonotic diseases. They come from wildlife. They spill over. The point of thinking about this subject, the point of knowing about it, the point of doing scientific research on zoonotic diseases, is to try to foresee the Next Big One, and to be ready to deal with it, insofar as possible. That’s why I wrote the book.

Related Link

Program | Spillover: Animal Infections and the Next Human Pandemic