October 31, 2007
The most widespread HIV subtype outside Africa likely emerged in Haiti in the 1960s and arrived in the U.S. a few years later -- about 10 years earlier than previously believed -- according to a study published Tuesday in the Proceedings of the National Academy of Sciences, the Los Angeles Times reports.
For the study, Michael Worobey, an evolutionary biologist at the University of Arizona, and colleagues analyzed five blood samples collected in 1982 and 1983 from Haitian HIV/AIDS patients in Miami that had been frozen and stored by CDC (Chong, Los Angeles Times, 10/30). In addition, the researches examined genetic data from 117 early HIV/AIDS patients worldwide (Dunham, Reuters, 10/29). The researchers examined two viral genes and compared their sequences with viruses found worldwide, using HIV samples from Central Africa considered to be some of the earliest forms of HIV as a baseline.
The researchers then constructed a timeline of HIV development by measuring how much the genes in recent blood samples differed from early samples. According to the study, samples from Haitians were genetically the most similar to the African virus, indicating the Haitian viruses were among the earliest to branch off. The researchers found a 99.7% certainty that HIV subtype B originated in Haiti, Worobey said.
"Once the virus got to the U.S., then it just moved explosively around the world," Worobey said (AFP/Yahoo! News, 10/29). Worobey added that there likely were "hundreds of thousands of infections" before HIV was discovered. Arthur Pitchenik, a study co-author from the University of Miami, said the study "gives [scientists] more clear insight into the history of" the HIV/AIDS pandemic and "what path the virus took" (Reuters, 10/29).
Worobey added that the study did a "good job of settling the debate" over whether the virus arrived in the U.S. from Africa or Haiti. "This shows quite clearly that the data is really only consistent with a Haiti-first origin," Worobey said. Beatrice Hahn, a virologist at the University of Alabama-Birmingham who was not involved with the study, said the study's "calculations are as good as the currently available methods allow." Hahn cautioned against blaming the spread of HIV/AIDS on Haitians or Central Africans. "These viruses are fairly clever, and they have to survive. They will find niches. ... You realize chance events play a very important role," Hahn said (Los Angeles Times, 10/30).
The Miami Herald on Wednesday examined how the study's findings have "stoked controversy among researchers and Haitians" by "reopening deep wounds over the medical community's role in perpetuating a stigma against people from the island" (Tasker/Charles, Miami Herald, 10/31).
NPR's "Day to Day" on Tuesday included a discussion with NPR science correspondent Richard Knox about the study (Brand, "Day to Day," NPR, 10/30). Audio of the segment is available online.
Reprinted with permission from kaisernetwork.org. You can view the entire Kaiser Daily HIV/AIDS Report, search the archives, or sign up for email delivery at www.kaisernetwork.org/dailyreports/hiv. The Kaiser Daily HIV/AIDS Report is published for kaisernetwork.org, a free service of the Kaiser Family Foundation, by The Advisory Board Company. © 2007 by The Advisory Board Company and Kaiser Family Foundation. All rights reserved.
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