New York Times Reports on Research into African Chimpanzees as Source of HIV-1

In a continuation of its "AIDS at 20" series, the New York Times today reports on the discovery of a virus highly similar to HIV-1 in a "long-dead" chimpanzee that may be "the missing link in the search for the origins of AIDS." In 1998, Dr. Beatrice Hahn of the University of Alabama-Birmingham and an international team of 11 other scientists examined the organs of a dead chimpanzee and "unravel[ed] the mystery of the origin of the epidemic." The chimp, which died a decade earlier while giving birth, came from west-central Africa, a region thought to have been the "place where the human AIDS epidemic began," as genetic sequences of HIV are most diverse there, indicating a long-time presence of the disease. In addition, some people in west-central Africa eat chimpanzees, making it "entirely reasonable to think that an infected animal's blood gave the virus to a person who was handling the chimpanzee meat, infecting the person and setting the stage for an AIDS epidemic," the Times reports. But until Hahn's examination of the chimp, many scientists had remained unconvinced that the animals were the source of the human epidemic. While researchers continue to find HIV-like viruses in other animals and primates in Africa, none are as closely related to HIV-1 as the virus found in Hahn's chimpanzee and two other viruses isolated earlier from two different chimps. Researchers now say they have identified two more chimps captured in the west-central African nation of Cameroon that carried a virus like HIV-1. From viral mutation calculations based on the chimp evidence, researchers estimate that the epidemic began in 1931, plus or minus 15 years, and "almost certainly infected humans repeatedly as they killed and ate chimpanzees over the years." Some researchers say that the epidemic was not detected until much later because "the conditions were ripe" for the disease to spread only after Africans began moving into cities and attending clinics where physicians often reused needles. Others suggest that it simply took many years for enough people to become infected to draw attention to the disease (Kolata, New York Times, 9/4).