A meticulous unfolding of how, when, where and why HIV took off.
Make that HIV-1, group M, as one thing Crawford (Medicine/Univ. of Edinburgh; The Invisible Enemy: A Natural History of Viruses, 2003, etc.) makes clear is that the world of simian and human immunodeficiency viruses (SIVs and HIVs) is rich, complex and constantly changing due to high mutation rates. By 1983, it was known that a virus was the cause of AIDS. Researchers quickly established that the “gay disease" in America was the same as the heterosexual “slim disease” in central Africa, both caused by a retrovirus of the lentivirus, or slow virus family, so-called because of the long lag time between infection and the end stages of disease. The canny observation of a similar disease in Asian macaques at the U.S. National Primate Centers spurred a focus on primates in Africa; there was reason to believe that the macaques had picked up an SIV from African primates there. How the simian virus jumped to humans is a tangled tale whose unraveling involved international collaborations among epidemiologists, demographers, virologists and evolutionary molecular biologists. The researchers eventually pinned down the origins of HIV-1 to chimpanzees in Cameroon, and the less aggressive HIV-2 disease to West African sooty mangabeys. Getting to that point meant digging into stored blood and tissue samples in Europe and Africa, testing captive primates, and developing techniques for extracting HIV antibodies and viral DNA from urine and fecal samples from primates in the wild. The current consensus is that HIV-1 cases date back to the 1900s and were amplified in the 1920s by mass vaccinations and unsterilized needles. AIDS became a pandemic in recent decades thanks to warfare, global travel, changing mores, movements to cities, the growth of commercial sex workers and the market for bush meat, to name only the most prominent in a vast array of factors.
A wonderful source book for professionals and a highly informative, often engrossing tale for lay readers willing to apply due diligence.