TUCSON, July 17 (UPI) -- A U.S. study suggested that monkey viruses related to the human immunodeficiency virus might have swept across Africa more recently than thought.
University of Arizona researchers have determined an HIV-like virus -- the simian immunodeficiency virus, or SIV -- first infected green monkeys after their lineage split into four species. The new research reveals the split occurred about 3 million years ago. Previously, scientists thought SIV infected an ancestor of green monkeys long before that split occurred.
"Studying SIV helps us learn more about HIV," said the study's first author, doctoral candidate Joel Wertheim. "This finding sheds light on the future direction of HIV evolution."
The study suggested that African green monkeys' SIVs may have lost their virulence more recently than the millions of years previously thought. If SIV was once a monkey killer, the change in its virulence might shed light on the future course and timing of the evolution of HIV.
The research also challenges the idea that one ancient SIV was transmitted vertically, down through time, and evolved into many SIVs as its original host diverged into many different species.
The research appears in the July issue of PLoS Pathogens.
