The Chimp and the River: How AIDS Emerged from an African Forest Read Online Free PDF Page A

hadn’t, so far as the records showed, yet been subjected to any experimental infection. They were using her in a study of diet and cholesterol. The New Iberia facility didn’t happen to work on leprosy infections, so once Louise’s condition had been recognized she was transferred to a place, also in Louisiana, that did: the Delta Regional Primate Research Center, north of Lake Pontchartrain. The researchers at Delta were glad to get her, for one very practical reason. If Louise had acquired her leprosy naturally, then (contrary to previous suppositions) the disease might be transmissible in populations of sooty mangabey. And if that were true, then the sooty mangabey could prove valuable as an experimental model for studies of human leprosy. This is how human medical research works: at the expense of other creatures.
    So the Delta team injected some infectious material from Louise into another sooty mangabey. This one was a male. Unlike Louise, he is nameless in the scientific record, remembered only by a code: A022. He became the first in a chain of experimentally infected monkeys that turned out to carry more than leprosy. The scientists at Delta had no idea, not at first, that A022 was SIV-positive.
    The leprosy from Louise took hold easily in A022, which was notable, given that earlier attempts to infect monkeys with human leprosy had failed. Was this strain of Mycobacterium leprae a peculiarly monkey-adapted variant? If so, might it succeed in rhesus macaques too? That would be convenient for experimental purposes, because rhesus macaques were cheaper and more available, in the medical-research chain of supply, than sooty mangabeys. So the Delta team injected four rhesus macaques with infectious gunk from A022. All four developed leprosy. For three of the four, that proved to be the least of their troubles. The unlucky three also developed simian AIDS. Suffering chronic diarrhea and weight loss, they wasted away and died.
    Screening for virus, the researchers found SIV. How had their three macaques become SIV-positive? Evidently by way of the leprous inoculum from the sooty mangabey, A022. Was he unique? No. Tests of other sooty mangabeys at Delta revealed that the virus was quite prevalent among them. Other investigators soon found it too, not just among captive sooty mangabeys but also in the wild. Yet the sooty mangabeys (native to Africa),unlike the Asian macaques, showed no symptoms of simian AIDS. They were infected but healthy, which suggested that the virus had a long history in their kind. The same virus made the macaques sick, presumably because it was new to them.
    The roster of simian immunodeficiency viruses was growing more crowded and complex. Now there were three known variants: one from African green monkeys, one from rhesus macaques (which they probably acquired in captivity), and one from sooty mangabeys. Needing a way to identify and distinguish them, someone hit upon the expedient of adding tiny subscripts to the acronym. Simian immunodeficiency virus as found in sooty mangabeys became SIV sm . The other two were labeled SIV agm (for African green monkeys) and SIV mac (for Asian macaques) . This little convention may seem esoteric, not to mention hard on the eyes, but it will be essential and luminous when I discuss the fateful significance of a variant that came to be known as SIV cpz .
    For now it’s enough to note the upshot of the leprosy experiment in Louisiana. One scientist from the Delta team, a woman named Michael Anne Murphey-Corb, collaborated with molecular biologists from other institutions to scrutinize the genomes of SIVs from sooty mangabeys and rhesus macaques, and to create a provisional family tree. Their work, published in 1989 with Vanessa M. Hirsch as first author, revealed that SIV sm is closely related to HIV-2. So is SIV mac . “These results suggest that SIV sm has infected macaques in captivity and humans in West Africa,” the group wrote, placing the onus of