Chimps are not the only animals that can harbor and introduce HIV into human populations, according to a new report. A 62-year-old woman, who recently arrived in Paris after living in Cameroon, is thought to be the first human to carry a strain of HIV originating in a gorilla.

The woman most likely got the virus from another person, since she claims not to have made contact with gorillas or meat from wild animals. This suggests she is not an isolated case. In fact, the authors note in Nature Medicine that the virus “could be circulating unnoticed in Cameroon or elsewhere.” [Scientific American is part of the Nature Publishing Group.]
“This demonstrates that HIV evolution is an ongoing process,” co-researcher David Robertson of the University of Manchester told BBC News. “The virus jumps from species to species, from primate to primate, and that includes us.”

Experts suggest there is no need for alarm. While the unique strain might be difficult to detect by conventional tests, researchers think it should still be sensitive to current cocktails of powerful antiretroviral treatments that can keep the replicating virus at bay. (See our recent feature on why these drugs can’t fully eradicate HIV.)

The new HIV strain is called RBF 168—or more simply the “P” variant of HIV—and is likely linked to a virus recently discovered in wild gorillas, according to the Nature Medicine paper. It joins three previously identified variants of HIV that originated in chimpanzees: M, N and O. (The M variant accounts for the majority of infections worldwide.) The authors observed that P replicates more rapidly than any of the other strains, which could mean that the virus has adapted to human cells.

However, given the number of variations in HIV, is it unlikely that one more will make a difference, Robert C. Gallo, who co-discovered HIV in 1984, told CNN. “Even if the new variant proves lethal,” he said, “it’s not likely to increase AIDS infections.”

Picture of gorilla family by guenterguni via iStockphoto