University of Texas at Austin InfoTrac Newspapers The New York Times, Jan 29, 2002 pF1(L) col 01 (39 col in) When H.I .V. Made Its Jump to People. (Science Desk) Gina Kolata. Full Text: COPYRIGHT 2002 The New York Times Company For several years now, Dr. Beatrice H. Hahn and Dr. George M. Shaw, AIDS researchers at the University of Alabama at Birmingham, have been well aware that the scientific evidence for the origins of AIDS had a few crucial gaps. And they intended to fill them. But, as their new research has now shown, AIDS viruses do not always behave as expected. The investigation began when the Alabama scientists and others argued that the AIDS virus causing the devastating human epidemic originated in chimpanzees. It jumped to humans decades ago, they said, probably when infected animals were killed and eaten. The evidence was three captive chimpanzees, all infected with a virus closely resembling the one that causes AIDS and all of a subspecies, Pan troglodytes troglodytes, that lives in west-central Africa. So, scientists hypothesized, AIDS originated there. Investigators also found a fourth captive chimpanzee that was infected with a genetically distinct AIDS-like virus. No one knew where this animal came from, but Dr. Hahn and others said it must be from somewhere other than west-central Africa -- its virus was just too different from the one in the other three animals. ''We had four chimp viruses, three that were closely related to each other and to the human strains,'' Dr. Hahn said. ''And they were different from a fourth strain. So we said, obviously, the west-central African chimps were the likely source'' of the human AIDS virus. But, she added, some scientists looked askance. ''Some said: Four chimps are not a lot. You don't know what happens in the wild,'' Dr. Hahn recalled. And so, she said, she and her colleagues set out to find a way to detect AIDS-like viruses in wild chimpanzees. Dr. Hahn and Dr. Shaw were pretty certain what they would find -- widespread infection with a virus that resembles the AIDS virus but does not make chimpanzees ill. After all, they reasoned, there must be a reservoir of infected chimpanzees if the virus had passed to people . The captive chimpanzees that were infected had not become ill. And researchers have found that other animals have their own AIDS-like viruses and are widely infected with them but do not become ill. Page 1 of 4Article 28/1/2002http://web3.infotrac.galegroup.com/itw/infomark/744/626/50552607w3/purl=rc1_SP00_0_...That story began more than a decade ago, when Marlo Brown, a resident of Petaluma, Calif., who ran a shelter for cats, was astonished to see that several of them were showing symptoms that looked like AIDS. She took them to a veterinarian, who was baffled. So she took the cats to Dr. Niels Pedersen, an animal virologist at the University of California at Davis, telling him they had AIDS. She turned out to be right. A year later, in August 1987, Dr. Pedersen and a research colleague, Dr. Janet Yamamoto, found the virus. It is a close cousin of the human AIDS virus, although it does not infect people . But where did it come from? Were wild cats infected too? And, if so, did that mean that endangered species like lions and pumas were going to get a version of AIDS, like the domestic cats, and be exterminated? Dr. Stephen O'Brien, a cat expert who is chief of the Laboratory of Genomic Diversity at the National Cancer Institute in Frederick, Md., intrigued and alarmed, began looking for the virus in a repository of serum from thousands of wild cats, including cheetahs, lions, ocelots and pumas. To his great surprise, it was everywhere, with a vast majority of wild cats carrying the virus. ''Every cat was infected with a virus that had the potential to kill the immune system,'' Dr. O'Brien said. But, somehow, those animals were not even ill. ''We spent a lot of time looking for a disease, but no one could find it,'' Dr. O'Brien said. It seemed that wild cats had somehow learned to live with the virus and not get sick. But domestic cats, which were new victims for the virus, were defenseless and quickly succumbed. Meanwhile, others were discovering the same pattern in primates, looking in the wild at monkeys that were not endangered, even kept as pets, and also examining captive animals. At least 20 species of African primates are infected with, but seemingly unaffected by, AIDS-like viruses. Asian monkeys, in contrast, were not infected. But when Asian monkeys in research laboratories were given the African monkey viruses -- either deliberately by researchers who were studying the viruses or accidentally because they were in cages with African monkeys -- the Asian monkeys contracted a disease that looked like AIDS. ''African primates all carry their own little viruses,'' said Dr. Jonathan S. Allan, a virologist at the Southwestern Foundation for Biomedical Research in San Antonio. ''In some species, the viruses have been there for thousands of years. And the natural host never gets sick.'' With this background, the challenge for Dr. Hahn and Dr. Shaw was to find a way to look for AIDS-like viruses in wild chimpanzees, which are a protected and endangered species. It is illegal to capture them or even to anesthetize them and take their blood. The investigators discovered that they could find identifying traces of the virus in feces and urine. They tested their methods, first with human feces and urine and then with feces and urine from chimpanzees in captivity. (Dr. Hahn said her students rebelled after testing human feces, saying they would not spend months working with such material. But chimpanzee feces, she added, turned out not to have an objectionable odor.) Finally, it was time to go into the wild, working with primatologists who study chimpanzees so closely that they know each animal in a colony. That allowed the researchers to trace every sample to a specific animal, to verify suspected infections by looking at more than one sample from an animal, and to observe whether infected animals were ill. Page 2 of 4Article 28/1/2002http://web3.infotrac.galegroup.com/itw/infomark/744/626/50552607w3/purl=rc1_SP00_0_...The primatologists collected urine and feces from 58 chimpanzees from colonies in the Tai Forest, a national park in Ivory Coast, in Kibale National Park in Uganda, and in Gombe National Park in Tanzania, and shipped the material to Dr. Hahn and her colleagues in the