The history of the United Kingdom's HIV-1 subtype B epidemic began with six separate introductions of the virus in the early to mid 1980s, rather than from one transmission, according to genetic research by Deenan Pillay, of University College London's Centre of Virology, and colleagues. HIV-1 subtype B is the United Kingdom's most common form of the virus and is transmitted there mostly among men who have sex with men. Study authors created a genetic family tree for HIV using samples taken from 1,645 U.K. patients and 1,784 samples of subtype B around the world. In the United Kingdom there was no epicenter for any of the epidemics, suggesting the carriers moved around the country, said researchers.
"Our study suggests that the HIV-1 subtype B epidemic currently circulating in the United Kingdom is made up of at least six established chains of transmission, introduced in the early and mid 1980s," said Pillay. "This goes against the prevailing belief that one initial entry of HIV-1 was responsible for the spread of the epidemic." (Reuters)