"HIV mutates rapidly," said Rebecca Gray, a postdoctoral associate in the department of pathology, immunology and laboratory medicine. "This is a successful strategy for the virus, because it evolves quickly and develops drug resistance. But we can use these changes in the genome to follow it over time and develop a history of its progress."
Researchers wanted to know why, the virus smoldered during the 1950s and `60s, before spreading like wildfire through east Africa in the 1970s.
A fateful piece of the puzzle came in the form of geographic information system data, which uses satellite imagery and painstakingly takes into account the availability and navigability of roads between population centers, transportation modes, elevation, climate, terrain and other factors that influence travel.
"We were able to use geographic data to interpret the genetic data," said Andrew J. Tatem, Ph.D., an assistant professor of geography in the College of Liberal Arts and Sciences and a member of UF's Emerging Pathogens Institute. "Genetic data showed once HIV moved out of the Democratic Republic of Congo, it expanded fast and moved rapidly across Uganda, Kenya and Tanzania, all while staying at low levels in the DRC. What was happening was the virus was circulating at stable levels in the urban centers of the DRC, but these centers were isolated. Once it hit east Africa, connectivity between population centers combined with better quality transportation networks, and higher rates of human movement caused HIV to spread exponentially."
HIV was prevalent in about 15 percent of the population in Kenya in 1997, although it has since dropped to about 7 percent, according to the Kaiser Family Foundation. As of 2007, an estimated 22 million people were living with HIV/AIDS in sub-Saharan Africa. About 1.1 million Americans have HIV or AIDS, and an estimated 5.1 millio
|Contact: John Pastor|
University of Florida