Tuesday, November 02, 2004

The Puzzling Origins of AIDS

Red Nova, which appears to be a popular science website, presents an article by Jim Moore, an anthropologist on the faculty of the University of California at San Diego, who has done some research on the question of where/how AIDS might have originated. The article, which may first have been published in Scientific American, outlines four competing theories of the origin of AIDS:
  • Tainted polio vaccine - chimpanzee or monkey tissue used to cultivate early polio vaccines in Africa may have allowed species crossover;
  • Cut hunter - indigenous hunters of various primates, especially chimpanzees, may have been exposed to a virus that crossed species;
  • Contaminated needles - inadequate health facilities may have spread a crossover virus in local populations;
  • Heart of darkness - labor and health practices in the former Belgian Congo may have spread a debilitating virus in forced labor camps.

Moore's conclusions do not point to the greater validity of one theory over another. Rather, he looks at the "lessons" to be drawn from them:

Given the precarious status of each of the current theories, it seems more reasonable to try to keep an open mind until better evidence emerges and, in the meantime, to consider the literature on each of these origin stories as representing a highly refined simulation scenario. Insofar as there is any material benefit to come from understanding the origin of HIV in terms of cautionary tales, each model can and should be considered plausible-and worrisome. After all, unsterile needles do transmit diseases, contaminated polio vaccine did spread a simian virus (one called SV40) to millions of people, doctors do sometimes conduct risky research, colonial policies did have major health consequences, and contact with wild animals can introduce pathogens into humans.

An obvious general lesson can be drawn from all four theories: For some very puzzling reason, the origin of HFV was not fundamentally natural, given that humans apparently failed to acquire an immunodeficiency virus from simians during thousands of years of exposure. Instead, the emergence of HIV involved social change in one form or another: the abuses carried out at the hand of an invading foreign power; abrupt urbanization overwhelming the ability of medical and political authorities to manage the process; the undersupervised transfer of medical technology and half- measures in development programs; doctors taking liberties in distributing medicines without adequate precautions. It is worth noting that three of the four theories postulate an origin for AIDS that involves the inadvertent results of medical efforts, with what were then state-of-the-art health programs and technologies carrying with them unforeseen dangers.

Whether understanding the origin of HIV and AIDS is useful for evaluating risks associated with present-day concerns (say, the consumption of wildlife that might be the natural reservoir for emerging diseases like SARS, or evaluating the likelihood that the transplantation of animal organs into people will unleash a dangerous new virus) is a matter of opinion. My own view is that a firmer grasp of what happened in the past-and what might easily have happened had circumstances been slightly different-helps society to understand these dangers and to minimize the risk of sparking the next global scourge. [Emphasis added.]

The article itself is interesting reading. Its conclusions might prod us into thinking more about the ways in which social and healthcare practices in the current environment promote the spread of HIV in the U.S.

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