Gorilla strain of AIDS crosses to French woman from Cameroon
A new strain of HIV has crossed from gorillas to humans, with a 62-year-old French woman from Cameroon so far the only person known to be infected.
Only one case has been detected, and it closely resembles strains of simian immunodeficiency recently discovered in western gorillas living in the wild, New Scientist reported Sunday.
“It would be surprising if there aren’t some more” human cases, said David Robertson, a bioinformaticist at the University of Manchester, who analyzed the virus’s DNA along with colleagues in France. “We don’t think this is a direct gorilla-to-human transmission.”
She has shown no signs of a compromised immune system. The woman, who lived in a suburb of Cameroon’s capital city Yaoundé until 2004, told reseachers she had no contact with gorillas, and they do not believe it was transmitted to her by a gorilla. It is presumed that she had sexual contact with another human who had the virus.
Tests on laboratory-cultured human cells suggest that the virus can replicate in the same white blood cells as other strains of HIV. However, the new virus should be susceptible to anti-retroviral drugs that slow the growth of other strains of HIV, Robertson said.
Based on its genetic sequence, the virus appears most closely related to a number of SIV strains collected recently in gorilla fecal samples from forests in Cameroon. These viruses also resemble “group O” strains of HIV, which infect far fewer people than other strains of HIV, most of them in Cameroon.
The discovery of a gorilla virus in humans could suggest that some of these group O viruses came from gorillas, Robertson said, but it’s also possible the virus originated in a chimpanzee and was transmitted independently to gorillas and to humans.
“Until we do more sampling, we’re also guessing a little bit,” Robertson conceded.
The discovery adds to growing evidence that new HIV strains may regularly emerge from other primates, said Martine Peeters, a virologist at the University of Montpellier, who led the team that identified the first gorilla SIV strains. “It is just an additional demonstration that these viruses have jumped several times from apes to humans.”
Virologists could be missing many of these transmissions because existing HIV tests are biased to identify already circulating strains of the virus. “We’re very good at detecting HIV, so unless you do these other more in-depth tests, you wouldn’t necessarily detect these very divergent viruses,” Robertson said.