title: The emergence of HIV/AIDS in the Americas and beyond.
abstract: HIV-1 group M subtype B was the first HIV discovered and is the predominant variant of AIDS virus in most countries outside of sub-Saharan Africa. However, the circumstances of its origin and emergence remain unresolved. Here we propose a geographic sequence and time line for the origin of subtype B and the emergence of pandemic HIV/AIDS out of Africa. Using HIV-1 gene sequences recovered from archival samples from some of the earliest known Haitian AIDS patients, we find that subtype B likely moved from Africa to Haiti in or around 1966 (1962-1970) and then spread there for some years before successfully dispersing elsewhere. A "pandemic" clade, encompassing the vast majority of non-Haitian subtype B infections in the United States and elsewhere around the world, subsequently emerged after a single migration of the virus out of Haiti in or around 1969 (1966-1972). Haiti appears to have the oldest HIV/AIDS epidemic outside sub-Saharan Africa and the most genetically diverse subtype B epidemic, which might present challenges for HIV-1 vaccine design and testing. The emergence of the pandemic variant of subtype B was an important turning point in the history of AIDS, but its spread was likely driven by ecological rather than evolutionary factors. Our results suggest that HIV-1 circulated cryptically in the United States for approximately 12 years before the recognition of AIDS in 1981.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
authors.forename: Andrew
authors.initials: A
authors.lastname: Rambaut
authors.forename: Gabriela
authors.initials: G
authors.lastname: Wlasiuk
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Spira
authors.forename: Arthur E
authors.initials: AE
authors.lastname: Pitchenik
authors.forename: Michael
authors.initials: M
authors.lastname: Worobey
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology; D000569:Americas; D004279:DNA, Viral / Q000235:genetics; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D013997:Time Factors
chemical_list: D004279:DNA, Viral