Ray Suarez has our conversation.

　　RAY SUAREZ: Since AIDS was first identified in the West 30 years ago, its toll across the world has been vicious. It's killed 25 people since 1981. An estimated 34 million are living with the virus today.

　　Just how the disease began and spread perplexed scientists for years. A new book tracks the emergence of the HIV virus out of a remote part of Cameroon to what is now Kinshasa in the former Belgian Congo. "Tinderbox: How the West Sparked the AIDS Epidemic and How the World Can Finally Overcome It" connects the economies and atrocities of colonialism to that initial outbreak and to current medical approaches to the treatment and prevention of HIV in Africa.

　　Craig Timberg and Daniel Halperin, welcome.

　　DANIEL HALPERIN, author: Thank you.

　　CRAIG TIMBERG, author: Thank you for having us.

　　RAY SUAREZ: The book is about a great many things, but one of the conclusions that's gotten a lot of attention is the responsibility of colonialism for helping AIDS break out of the deepest rain forests into the rest of the world. How does that happen?

　　CRAIG TIMBERG: Well, the virus that became HIV was infecting a community of chimpanzees for hundreds of years, probably thousands of years. And scientists now theorize that it actually made its way into the human population several times over centuries.

　　As humans caught infected chimps, butchered them, the blood probably passed through a cut. What's crucial about the moment that leads to the actual AIDS epidemic is that at that exact moment, there are new intrusions of steam ships and porter paths as humans move into these remote places where the chimpanzees lived.

　　And it's at that moment when HIV becomes a human epidemic, starts moving down the rivers and into the birthplace of the epidemic, if you will, in Central Africa.

　　DANIEL HALPERIN: And even to this day, there are small strains of HIV virus that exist. For example, in Cameroon, there are more strains of the virus than anywhere else in the world.

　　And some of these strains probably originated during the last century, in other words, are more recent than the strain that has caused over 99 percent of the deaths by AIDS in the world. So we hypothesized that if it hadn't been for the role of colonialism, that what we now know today as the type of HIV virus that has become this hugely global problem might likely have become like these other strains we have seen in Cameroon. It may have gone out and infected a few hundred or a few thousand people. But we may never even have known about it because it's a fairly remote part of the world.

　　CRAIG TIMBERG: And this is a place that was one of the most sparsely populated parts of a very sparsely populated continent.

　　And so were it not for the intrusions of colonialism, it's unlikely that the epidemic we know today would have come out in the way that we have seen it, and in particular that they have been able to track porter paths, where Africans are force marched to the jungle. They're carrying guns and ivory tusks and rubber. They have been able to track that to exactly the place where these chimpanzees lived.

　　And there would have no reason for those people to go there before. They went there because they were forced to go there. And they come down these porter paths, they go to these trading stations, they get on steam ships. And that becomes the actual spark for this epidemic.

　　DANIEL HALPERIN: We can now see in retrospect that this was going on.

　　And that perhaps gives us a little bit insight hopefully into how to approach the problem today, that, as Westerners, we are not merely bystanders who care about what happened in Africa, but in a sense we have a little bit perhaps of responsibility to help remedy a situation that we may have partly helped to have initiated.

　　RAY SUAREZ: What happened in later decades, in the '60s, '70s, and '80s, to allow HIV to become so deeply rooted in Africa and also break out to the rest of the world?

　　CRAIG TIMBERG: The two very important things happened in the middle part of the 20th century.

　　One is that HIV makes its way on the railroads, on the highways into the parts of Africa where male circumcision, which is an ancient tradition in much of the continent, is not in fact a tradition. So when you cross over the mountains, and you're suddenly in East Africa, you're in the areas where men aren't circumcised.

　　And, suddenly, instead of having infection rates of 1 percent, 2 percent, you get infection rates of 5 percent, 10 percent, 15 percent. You see the kind of the disaster that we're more familiar with, where entire villages, you know, lose a huge percentage of their adults.

　　And that kind of problem also moves into Southern Africa, where also you have lower rates of male circumcision. And the other crucial thing that happens is HIV makes its way to the Americas. It makes its way from Kinshasa in the 1960s to Haiti. And that's where eventually it works its way into the Americas, it works its way into the gay American population, and it spreads much more widely eventually.

　　RAY SUAREZ: But the shadow of colonialism is never really gone from Africa, is it? When it comes to the way we look at AIDS, look at AIDS sufferers, talk about and to the people who are HIV-positive, how do you explain that part of it in your book?

　　DANIEL HALPERIN: We believe, of course, that the Europeans and North Americans and other foreigners who are in Africa now and other places trying to help people with epidemic are in one sense completely different from the colonials who were there a hundred years ago. They're not there to rape and to plunder, so to speak.

　　They're there with good intentions. They want to help deal with this and other diseases. But there's unfortunately a little bit of a kind of paternalism or a hubris maybe that continues, a sense of, we're the experts, we know what to do.

　　RAY SUAREZ: There's been a lot of coverage in the book of the sort of condescending, paternalistic, tsk-tsk way of looking at African societies where people were changing their behavior and not getting much credit for it.

　　CRAIG TIMBERG: When you look at what happened in societies when they faced this problem, several of them sort of did the math. Right? They were faced with an incurable disease. It was spread by sex. It was fatal.

　　And in several societies, the leaders of the societies, politicians singers, religious singers, led campaigns in which they said, if we're going to survive, we need to make changes in our own sexual behaviors as a society. And that ends up being enormously consequential when you're dealing with a sexually transmitted epidemic.

　　RAY SUAREZ: You don't have a lot of love for the efforts to use high-tech responses, particularly in the African epidemic, whether it's antiretrovirals or universal urging to use condoms. Sort of technical fixes don't really get a lot of praise in this book.

　　And I think you conclude that they're not going to work in the African context. Why?

　　CRAIG TIMBERG: These drugs are miraculous, right? This medicine brings people back from the edge of death.

　　And anyone who's watched that happen understands the power of that. And we want as many people to be treated as possible. And what—the issue we raise is, it's not enough to treat people who already have this virus. To really win the fight against the epidemic, you need to prevent the next million, the next 10 million infections from happening.

　　And, now, drugs may play a role in that, but we think that the most powerful role in the end will be played by the kind of things we're talking about here, changes in sexual behavior, increasing the prevalence of male circumcision. And that's what history shows.

　　RAY SUAREZ: The book is "Tinderbox: How the West Sparked the AIDS Epidemic and How the World Can Finally Overcome It."

　　That's a pretty big ambition in that title.

　　(LAUGHTER)

　　RAY SUAREZ: Craig Timberg and Daniel Halperin, thank you both.

　　DANIEL HALPERIN: Thank you, Ray.

　　CRAIG TIMBERG: Thank you, Ray.

　　DANIEL HALPERIN: This was wonderful.