Read Online The Chimp and the River: How AIDS Emerged from an African Forest by David Quammen - Free Book Online
Authors: David Quammen
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retroviruses. She moved next to the University of Alabama at Birmingham, where she became Professor of Medicine and Microbiology and codirector of a center for AIDS research, with a group of bright postdocs and grad students working under her aegis. (She remained at Alabama from 1985 to 2011, a period encompassing most of the work described here, and then joined the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia.) The broader purpose of Hahn’s various projects, and the goal she shares with Worobey, is to understand the evolutionary history of HIV and its relatives and antecedents. The fittest label for that sort of research is the one Worobey mentioned when I asked him to describe hisfield: molecular phylogenetics. A molecular phylogeneticist scrutinizes the nucleotide sequences in the DNA or RNA of different organisms, comparing and contrasting, for the same reason a paleontologist scrutinizes fragments of petrified bone from extinct giant saurians—to learn the shape of lineages and the story of evolutionary descent. But for Beatrice Hahn especially, as a medical doctor, there’s an additional purpose: to detect how the genes of HIV function in causing disease, toward the prospects of better treatment, prevention, and maybe even a cure.
Some very interesting papers have come out of Hahn’s laboratory in the past two decades, many of them published with a junior researcher as first author and Hahn in the lab leader’s position, last. That was the case in 1999, when Feng Gao produced a phylogenetic study of SIV cpz and its relationship to HIV-1. At the time there were only three known strains of SIV cpz , all drawn from captive chimps, with Gao’s paper adding a fourth. The work appeared in Nature, highlighted by a commentary calling it “the most persuasive evidence yet that HIV-1 came to humans from the chimpanzee, Pan troglodytes. ” In fact, Gao and his colleagues did more than trace HIV-1 to the chimp; their analysis of viral strains linked it to individuals of a particular subspecies known as the central chimpanzee, Pan troglodytes troglodytes , whose SIV had spilled over to become HIV-1 group M. That subspecies lives only in western Central Africa, north of the Congo River and west of the Oubangui. So the Gao study effectively identified both the reservoir host and also the geographical area from which AIDS must have arisen. It was a huge discovery, as reflected in the headline of Nature ’s commentary: FROM PAN TO PANDEMIC. Feng Gao at the time was a postdoc in Hahn’s lab.
But because Gao based his genetic comparisons (as Martine Peeters had done earlier) on viruses drawn from captive chimps, the soupçon of uncertainty about infection among wild chimpanzees remained, at least for a fewmore years. Then, in 2002, Mario L. Santiago topped a list of coauthors announcing in Science their discovery of SIV cpz in the wild.Santiago was a PhD student of Beatrice Hahn’s.
The most significant aspect of Santiago’s work, for which he got his richly deserved doctorate, was that on the way toward detecting SIV in a single wild chimpanzee (just one animal among fifty-eight tested), he invented methods by which such detections could be made. The methods were “noninvasive,” meaning that a researcher didn’t need to capture a chimp and draw its blood. The researcher needed only to follow animals through the forest, get under them when they pissed (or, better still, send a field assistant into that yellow shower), collect samples in little tubes, and then screen the samples for antibodies. Turns out that urine could be almost as telling as blood.
“That was a breakthrough,” Hahn told me, during a talk at her lab in Birmingham. “We weren’t sure it would work.” But Santiago took the risk, cooked up the techniques, and it did work. The very first sample of SIV-positive urine from a wild chimpanzee came from the world’s most famous community of chimps: the ones at Gombe
Some very interesting papers have come out of Hahn’s laboratory in the past two decades, many of them published with a junior researcher as first author and Hahn in the lab leader’s position, last. That was the case in 1999, when Feng Gao produced a phylogenetic study of SIV cpz and its relationship to HIV-1. At the time there were only three known strains of SIV cpz , all drawn from captive chimps, with Gao’s paper adding a fourth. The work appeared in Nature, highlighted by a commentary calling it “the most persuasive evidence yet that HIV-1 came to humans from the chimpanzee, Pan troglodytes. ” In fact, Gao and his colleagues did more than trace HIV-1 to the chimp; their analysis of viral strains linked it to individuals of a particular subspecies known as the central chimpanzee, Pan troglodytes troglodytes , whose SIV had spilled over to become HIV-1 group M. That subspecies lives only in western Central Africa, north of the Congo River and west of the Oubangui. So the Gao study effectively identified both the reservoir host and also the geographical area from which AIDS must have arisen. It was a huge discovery, as reflected in the headline of Nature ’s commentary: FROM PAN TO PANDEMIC. Feng Gao at the time was a postdoc in Hahn’s lab.
But because Gao based his genetic comparisons (as Martine Peeters had done earlier) on viruses drawn from captive chimps, the soupçon of uncertainty about infection among wild chimpanzees remained, at least for a fewmore years. Then, in 2002, Mario L. Santiago topped a list of coauthors announcing in Science their discovery of SIV cpz in the wild.Santiago was a PhD student of Beatrice Hahn’s.
The most significant aspect of Santiago’s work, for which he got his richly deserved doctorate, was that on the way toward detecting SIV in a single wild chimpanzee (just one animal among fifty-eight tested), he invented methods by which such detections could be made. The methods were “noninvasive,” meaning that a researcher didn’t need to capture a chimp and draw its blood. The researcher needed only to follow animals through the forest, get under them when they pissed (or, better still, send a field assistant into that yellow shower), collect samples in little tubes, and then screen the samples for antibodies. Turns out that urine could be almost as telling as blood.
“That was a breakthrough,” Hahn told me, during a talk at her lab in Birmingham. “We weren’t sure it would work.” But Santiago took the risk, cooked up the techniques, and it did work. The very first sample of SIV-positive urine from a wild chimpanzee came from the world’s most famous community of chimps: the ones at Gombe
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