Gorillas harbour AIDS-like virus

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gorillaPARIS (AFP) - Gorillas appear to be widely infected by a close relation to the AIDS virus, according to a study that appears in the British journal Nature.

French scientists made the startling discovery -- which has wide implications for the illegal market in bushmeat -- as they were looking for traces of the simian immunodeficiency virus (SIV) among chimpanzees.

Chimpanzees have already been closely implicated in the origin of AIDS. The apes are believed to have initially spread SIV to Man, where the agent mutated into a form that adapted to a human host -- the human immunodeficiency virus (HIV).

Martin Peeters and Eric Delaporte of the Institute for Development Research (IRD) and the University of Montpellier, southern France, analysed more than 500 faecal samples deposited by chimps and gorillas in remote forests in Cameroon.

Forty of the 323 chimp faeces had antibodies that reacted against the HIV-1 strain, which was consistent with previous findings. But, quite unexpectedly, so did six of the 213 gorilla samples.

Genetic analysis of the infected gorilla faeces showed that the sub-type, called SIVgor, was very close to the subtype O of HIV-1 lineage, which is found among humans in central west Africa.

As the faecal samples came from gorillas that live nearly 400 kilometers (250 miles) apart, it is likely that the apes' infections were not coincidental but a sign that SIV is endemic among their species, the authors say.

Gorillas are classified into two species -- Gorilla gorilla, the western African species, and Gorilla berengei, the eastern species, which in turn is sub-divided into four sub-species.

Still unclear is whether the eastern species is infected by the virus as the western species appears to be.

As to the cause, the finger points at chimpanzees. Pan troglodytes probably infected gorillas as well as humans with SIV, the study says.

"Gorillas are hunted for food and medicinal use, and it is possible that these practices may have been responsible for the HIV-1 group O zoonosis (animal-borne pathogen)," the study says. SIV-infected gorillas "could pose an ongoing risk to humans."

At the end of last year, 38.6 million people were living with the human immunodeficiency virus, the agency UNAIDS reported in May.

The disease was first detected among a small number of homosexuals in California in 1981. It has since killed around 25 million people.

One theory, based on a "molecular clock" on the rate at which the virus mutates, suggests the virus leapt from ape to man in the 1920s or 30s. The speculation is that this occurred through a bite or by a hunter who handled infected meat and received the virus through a cut.

source - AFP