Part 4: The Virus, Past and Future

There Are Two AIDS Epidemics—and More May Be Coming

Additional articles in this series.

Franceville, Gabon —Primatologist Caroline Tutin was boarding a flight from her home in Africa when a baby in toddler clothes and sunbonnet caught her eye. Then she did a "horrendous double-take." The baby was a chimpanzee. The animal's French owners, who lived in equatorial Gabon, were childless and they treated the animal as their baby, even giving it its own room, decorated like a little girl's.

About 10 years ago, Amandine, as they had named the chimp, became ill. Its owners—who insisted on being called its parents—took the animal to Gabon's Centre International de Recherches Medicales, Franceville (CIRMF), a world-class primate center. The scientists never discovered what was ailing the ape, but they did find another connection to human beings besides Amandine's wardrobe and the more than 98 percent of DNA that chimps and people have in common. Amandine was the first chimpanzee found to be infected with SIV, the simian equivalent of HIV.

Karakoula Bertheloise, shown here with his wife, is a hunter in the Cameroon rainforest. He hunts whatever game he can, including monkeys and apes.
photo: Mark Schoofs
Karakoula Bertheloise, shown here with his wife, is a hunter in the Cameroon rainforest. He hunts whatever game he can, including monkeys and apes.

Because of the genetic similarity between the chimp and human viruses, it appeared that HIV had

originated in chimpanzees—a theory all but confirmed in February of this year by University of Alabama researcher Beatrice Hahn, who appears to have identified the exact chimpanzee subspecies—Pan troglodytes troglodytes—that harbors HIV's mother virus.

This finding is no mere historical anomaly. There is strong evidence that the virus has jumped from animals to humans on at least seven occasions. Unfortunately, the way this critically important science has been reported is undermining its credibility in Africa, the very place where most new variants of HIV are arising.

When Hahn presented her findings to about 5000 AIDS researchers in Chicago, she emphasized how the virus could have passed from apes to humans through the hunting and butchering of chimpanzees—a common practice that has provided protein for rainforest Africans over many centuries. But the hunting of "bush meat" has become commercialized, pushing the apes toward extinction. To emphasize her point, Hahn showed slides of slaughtered chimps. The normally staid scientific audience groaned in disgust, and it wasn't long before eating chimps was compared to cannibalism in The New York Times Magazine.

To many Africans, this was one more sign that nothing about Western thinking could be trusted, including science. Based on the media reports, many Africans dismissed the research as just another tool to denigrate their culture. "In France you eat frogs and oysters, which to us is very strange," says Léopold Zekeng, director of Cameroon's national HIV research program. Eating monkeys and apes, he says, "is part of our culture." Portraying it as barbaric could backfire, Zekeng warns: "Politicians could close up and say, 'We don't want you to do research because you might come out with findings that lead to more discrimination.' "

In fact, research into the origin of AIDS could help save Africans and everyone else, because the virus is still emerging: still mutating and moving from apes and monkeys into humans.

Zekeng vividly remembers the 26-year-old patient he calls Miss A. In 1991, she came to his lab in Cameroon's capital, Yaoundé, with "all the symptoms of AIDS—diarrhea, fever, weight loss, swollen lymph nodes. I was 200 percent sure she would test HIV-positive." But she didn't. Zekeng took her blood to a sophisticated German lab and discovered that the woman was infected with a new, previously undocumented variant of HIV called Group O. It is so genetically distinct that scientists believe it didn't evolve from the main strains of HIV, but represents a separate transmission from chimps to humans. Eighteen months after Miss A came to Zekeng's office, the virus had killed her.

Just last year, another team of researchers found a variant of HIV, Group N, that is more closely related to the chimp virus than any yet found in humans. As with Group O, scientists say it entered humans through its own cross-species transmission. And it, too, eluded conventional blood tests.

"I still see patients with the clinical symptoms of AIDS, yet they turn out HIV-negative using all assays," says Zekeng.

"The AIDS viruses are not over," agrees Preston A. Marx, another expert in the evolution of HIV, who works at the Aaron Diamond AIDS Research Center. "We have the potential for more to come. It's possible we could develop an AIDS vaccine and have viruses that the vaccine doesn't work against. This isn't science fiction. New viruses are still emerging, viruses that can cause AIDS."

In the mild rainforest evening, along a red-dirt logging road in southern Cameroon, the palm wine flows freely as a group of villagers talk around an open fire. The men all hunt, taking whatever the forest yields, from the small antelope called duikers to the great apes. "Our parents were hunters, and their parents," says Gerard Ampoh Mentsilé.

But hunting has changed. In addition to spears and snares, the hunters now use guns, some homemade from truck axles. Bullets are expensive, so they get them from poachers who sell the bush meat in cities. Sometimes bullets constitute the hunters' only payment. When they get paid in cash, they use themoney to buy soap or fuel for their gas lanterns. No one here has electricity.

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