Study pushes back origin of AIDS pandemic
By Julie Steenhuysen
CHICAGO (Reuters) - The deadly AIDS virus first began spreading among humans at the turn of the 20th century in sub-Saharan Africa, just as modern cities were emerging in the region, U.S. researchers said Wednesday.
The finding pushes back the origin of the human immunodeficiency virus (HIV) by several decades, they reported in the journal Nature.
Researchers think the growth of cities -- and high-risk behavior associated with urban life -- may have helped the virus to flourish. There is no cure for AIDS, which is most commonly transmitted through sexual contact.
Prior estimates put the origin of HIV at 1930. But Michael Worobey of the University of Arizona in Tucson now believes HIV began infecting humans between 1884 and 1924.
The research is based on 48-year-old gene fragments dug from a wax-embedded lymph node from a woman in Kinshasa in the Democratic Republic of Congo, formerly Zaire.
The 1960 sample is the second-oldest genetic sequence of HIV-1 group M, the main strain of the virus responsible for the AIDS pandemic.
The oldest sequence came from a 1959 blood sample given by a man in Kinshasa, formerly known as Leopoldville.
"Once you have two you can line them up and compare them," Worobey said in a telephone interview. Continued...