Belief that polio vaccine can spread AIDS has hampered the World Health Organization's efforts to stamp out polio. In Nigeria, several states recently banned use of the vaccine. Nigeria now has the highest number of polio cases in the world.
Although scientists agree that HIV comes from a chimpanzee simian immunodeficiency virus (SIV) that infected humans, when and how SIV jumped the species barrier has not been definitively determined.
The researchers found and sequenced genetic material from a new strain of SIV present in wild chimpanzees in the Kisangani region of the Democratic Republic of Congo (DRC).
The new SIV is not the one from which HIV-1, the virus responsible for the human AIDS pandemic, originated. The research shows that the new SIV resides on a different part of the SIV family tree.
One theory about the origin of HIV-AIDS alleges that tissues from chimps from the vicinity of Kisangani were used in preparing oral polio vaccine, thus letting the vaccine be contaminated by SIV.
"We found a new simian immunodeficiency virus, SIVcpzDRC1," said Michael Worobey, an assistant professor of ecology and evolutionary biology at the University of Arizona in Tucson. "It's a new variant of SIV, and it's not closely related to HIV-1." Finding the new strain of SIV in chimpanzees near Kisangani shows that HIV-1 did not originate from polio vaccines that were tested in that area in the 1950s.
The team's research article will be published in the April 22 issue of the journal Nature.
Worobey's coauthors are Beatrice H. Hahn, George M. Shaw, Mario L. Santiago, and Brandon F. Keele of the University of Alabama in Birmingham, Jean-Bosco N. Ndjango, Bernard L. Labama and Benot D. Dhed'a of the University of Kisangani in the Democratic Republic of Congo,
Contact: Michael Worobey
University of Arizona