Though Ebola is unlikely to gain a substantial foothold in the United States, even after the first U.S. diagnosis of an Ebola case this week, author David Quammen argues that our common humanity calls on us to help the people of West Africa. The virus has killed more than 3,400 people there and infected thousands more, according to the World Health Organization, and continues to spread at an out-of-control rate. (Related: "Ebola Questions You Were Afraid to Ask.")

Talking from his home in Montana, Quammen, author of Ebola: The Natural and Human History, describes how he first encountered the story of the disease over a campfire in Gabon; how sorcery and science are often at loggerheads in West Africa; and why we should try to imagine ourselves confronting the dire poverty that many Africans face.

How worried should we be about this first case of Ebola in the U.S.?

We should not be worried for ourselves. We should be more worried for the people in West Africa. This is a virus that does not easily spread from one human to another. It requires contact, direct contact with bodily fluids. It can be stopped with good hospital conditions and barrier nursing, meaning masks, goggles, rubber gloves, etc.

There is only the slimmest likelihood that it can escape that containment in the U.S. There's a far greater chance that we'll die of influenza in the next year than that we'll die of Ebola virus. But we should still be very concerned for what's going on in West Africa.

I suppose the next question is: Why are people in West Africa touching bodies or getting bodily fluids on each other? How is it spreading there? And why?

The severity of this outbreak in West Africa reflects not only the transmissibility of the disease, but also the sad circumstances of poverty and the chronic lack of medical care, infrastructure, and supplies. That's really what this is telling us: that we need to try harder to imagine just what it's like to be poor in Africa. One of the consequences of being poor in Africa, especially in a country like Liberia or Sierra Leone, which have gone through a lot of political turmoil and have weak governance and a shortage of medical resources, is that the current outbreak could turn into an epidemic.

It's being spread because people are taking care of their loved ones at home. They're touching them, they're feeding them, they're washing them, they're cleaning up the vomit and the diarrhea that Ebola generates. That's a classic circumstance in which even health care workers are getting infected.

In addition, there are burial practices that involve washing the bodies and in some cases cleaning out the body cavities. In some cases, the funeral practices also involve a final touch or even a final kiss of the deceased person. And one of the things that's particularly nefarious about Ebola is that it continues to live in a dead person for some period of time after death. A person who's been dead for a day or two may still be seething with Ebola virus. So funeral practices can be a big factor in allowing it to be transmitted.

It's a combination of horrible circumstances. But the primary factor is poverty.

There's a cultural dimension to the way that disease is interpreted in Africa, isn't there? A kind of standoff between sorcery and science.

That's absolutely true. I know a little bit more about that element among the ethnic peoples of central Africa than West Africa. But in both regions there's a belief that these mysterious, invisible plagues are caused by sorcery and evil spirits—what we might call putting hexes on people.

There's a belief in some cultures that if a person experiences good fortune in financial terms and does not share the good fortune, when that person becomes ill with a mysterious fever and dies, people tend to say: "Aha! It was because he didn't share. It was the spirits who brought him down." There's also a belief in some cultures that if someone doesn't share, another person will direct these evil spirits to take that person down. There are a lot of different beliefs from culture to culture that involve the idea of sorcery. And that just adds to the confusion and the capacity for transmission.

When and where did Ebola first appear?

The first known outbreaks were in central Africa, in 1976: one in Zaire, the country that's now the Democratic Republic of the Congo, and one in Sudan. The Zaire outbreak is the more famous. It began in a place called Yambuku, a little mission town in north central Zaire. People were suddenly dying with these horrible symptoms, but nobody knew what it was. An international team led by Karl Johnson went in, and it was this team that first isolated and identified the virus. They named it after a nearby river, the Ebola River.

You write that "every newly emerging disease begins with a mystery." What's the riddle behind Ebola?

There are a couple of mysteries. The main one is: Where does it live when it's not killing humans? In other words, what is its reservoir host? What kind of creature living in the African forest harbors this virus in a chronic, inconspicuous, but permanent way? Viruses have to live somewhere. They can only replicate in living creatures. So, when the Ebola virus disappears between outbreaks, it has to be living in some reservoir host, presumably some species of animal.

But after 38 years since the first outbreak, scientists have yet to identify for certain what the reservoir host of Ebola is. It is suspected that at least one of its reservoir hosts is a fruit bat. Antibodies to Ebola have been found, but no one has ever isolated live Ebola virus from a fruit bat or from any other creature. So we still don't know where this thing lives. And until we do, we can't foresee or forestall further outbreaks.

View Images Michael Fay sits behind author David Quammen on a boat in Africa, accompanied by pygmy tribesmen. The author first heard stories about Ebola from villagers in Gabon. Photograph by Michael Nichols, National Geographic Creative

You first came across Ebola while playing Stanley to Michael Fay's Livingstone on the Megatransect in 1999. Set the scene for us.

Michael is this wonderfully hard-bitten, adventuresome American ecologist who decided to walk 2,000 miles across the last remaining intact forest of central Africa in river sandals and shorts. [Laughs] And he did that for 456 days, surveying what he saw, taking notes of animal and plant populations.

I was assigned by dear National Geographic to be one of two fellows who would document this expedition. The other was the photographer Nick Nichols. We walked with Mike for long stretches. We were crossing a forest in northeastern Gabon that was known to be Ebola habitat. There had been an Ebola outbreak nearby that had killed several dozen people. It had been a horrible outbreak, which was famous in the medical literature. I had read about it before I went over there.

And the first night round the campfire I met these two Gabonese fellows who were working as forest crew for Mike. They started talking in French about the time when Ebola struck their village, killing their friends and loved ones—how horrible it was. Later on the walk, one fellow mentioned something really strange. He told me that when the outbreak hit the village, they also found 13 dead gorillas lying nearby in the forest.

That was riveting to me to hear. I knew from the scientific literature that Ebola kills gorillas and chimpanzees as well as humans. But this was the direct manifestation of the connectedness, by way of this disease, of humans, gorillas, and chimps. And the forest itself.

The term you use for Ebola's transmission from animals is "spillover." The technical term is zoonosis. Explain how that works.

Zoonosis is an animal infection that's transmissible to humans. It could be a virus. It could be a bacterium. And the animal in which it lives inconspicuously is the reservoir host. The moment when it passes from that reservoir host into another species is the event called spillover.

So, for instance, Ebola occasionally comes out of its reservoir host and might infect a chimpanzee; then the chimpanzee falls dead in the forest. That was a spillover from the reservoir to the chimpanzee. Then humans might come along and find the dead chimpanzee carcass and say, "Hurrah! Fresh meat!" And take it back to the village, butcher it, and eat it. Thus it would pass from the chimpanzee into humans, in another stage of the spillover.

That's what happened in a village called Mayibout 2. It was a chimpanzee brought back by some boys who had gone hunting. People ate it and got sick. Later, it was established that the boys had not killed the chimpanzee. They had found the chimpanzee lying dead in the forest. And the chimp was hot with Ebola virus.

Bill Gates has just given $50 million to help fight Ebola. As you tell that story, it seems to me that money desperately needs to be spent on basic health education and hygiene: Don't eat dead chimps.

That's absolutely right. Don't eat dead chimps. Don't eat monkeys. Don't eat any dead animals you find in the forest. Education along those lines is a very important part of it. It's a wonderful and a smart thing Gates and his wife have done, putting serious money into this outbreak.

A good portion of it, I gather, has gone to Nigeria, where the Gates Foundation had already been supporting an anti-malaria project. Some of the money was used to turn the anti-malaria facility into an Ebola treatment facility. And one consequence is that, as of this week, the Nigeria outbreak has reportedly been stopped. So that's enormously beneficial and valuable. But those kinds of resources—and much more—are now desperately needed in the three West African countries: Liberia, Sierra Leone, and Guinea.

Most of us know ebola from the book Hot Zone, by Richard Preston, and the movie Outbreak, which it inspired. In both, Ebola is portrayed as something from a zombie movie, with blood gushing from every orifice. One of the experts you quote derides this as fiction. What do you say?

I don't have any desire to argue or to belittle one of my colleagues, Richard Preston. He's a very fine writer. But when I started talking with Ebola experts and the subject of Hot Zone came up, they would take issue with the notion that Ebola is this preternatural force that causes bodies to essentially liquefy internally and bleed out.

That's a misapprehension. It is sometimes bloody. Frequently it is not at all bloody. It causes diarrhea, and the diarrhea is sometimes bloody. It causes vomiting, and the vomiting is sometimes bloody. But it is not invariably bloody. That is not a good diagnostic sign.

People need to understand that as horrible as this disease is, it's caused by a virus that has to achieve transmission through bodily fluids. It kills people by shutting down their organs or destroying their immune system. In fact, we don't really know yet exactly how it kills people. But it does not cause them to dissolve or to melt down.

View Images Members of the Red Cross remove the body of a suspected Ebola victim in a village in Sierra Leone. Photograph by Samuel Aranda, Redux

The current outbreak has killed more than 3,400 people. It's also wiped out the fragile recovery in places like Liberia and Sierra Leone after decades of civil war and drained resources from the fight against other diseases.

Absolutely. It's not just the toll directly from Ebola that is the tragedy. It's the indirect toll too—the destruction of the economy and education, as well as the health care system. People are dying more of malaria and pneumonia and childhood diarrheal diseases because the health care system has been overwhelmed with Ebola. And there's a real possibility that if it's not stopped, it'll destroy Liberia for generations to come.

Ebola kills in a gruesome way. It also seems to bring out the best in humanity. National Geographic did a piece about the nurses and health care workers on the front line. They seem to truly represent the spirit of Florence Nightingale, don't they?

The people who are working to help contain and stop this outbreak are heroic on a scale above the heroism of most medical responders. Not only is this an awful disease, it's also a very scary one. It may require direct bodily fluids for transmission, but if you're there up to your elbows, day after day, trying to care for and comfort people who are vomiting and having diarrhea and in some cases bleeding, you're exposing yourself in a very dangerous way. We've seen that from the toll among health care workers. I can hardly imagine anybody doing anything more heroic than what they're doing.

You've stared death in the face. How has writing this book changed your perspective on life?

I've been in an Ebola habitat, and I've talked to a lot of people. But I should emphasize that I've never been present during an outbreak. I asked the CDC whether I could embed with them during an outbreak response, but they said, "Absolutely not. We don't let writers tag along in those circumstances."

So I haven't endured anything like the risk that these health care workers are taking. I've gone with scientists into the field looking for Ebola and other emerging viruses. And there's a certain risk in that. But not anything like being in an outbreak response.

How has it changed my view of things? It's vividly emphasized to me that those of us who live in the Western world, with the advantages of health care and comforts and shelter and food, can scarcely imagine what it's like to be poor in Africa or in any tropical country where you've got emerging diseases coming out of the forest.

But we should try to imagine that. I love sitting here in Montana, but I can't forget what it's like out there in that other world. In many ways, it is more real than the world where I live.