Woman Contracts Gorilla HIV: Proof of Direct Connection between SIV and HIV /AIDS

A new strain of HIV has jumped from gorillas to humans.

So far, only one person, a 62-year-old French woman from Cameroon, has been reported to be infected with the virus.

It very closely resembles strains of Simian Immunodeficiency Virus (SIV) recently discovered in western gorillas in the wild.

"It would be surprising if there aren't many more" human cases, says David Robertson, a bioinformaticist at the University of Manchester, UK who analysed the virus's DNA along with colleagues in France.

"We don't think this is a direct gorilla-to-human transmission." It is more likely to be the result of eating 'Bush meat', plus transmission via sexual activity.

Drug hope

Until 2004, the infected woman lived in a suburb of Cameroon's capital city Yaoundé, where she didn't come into contact with apes or eat their meat, SIV's primary route to humans. This means that she probably acquired the infection from another human, likely through sexual contact.

AIDS

The woman hasn't yet shown any sign of a compromised immune system, the hallmark of AIDS but 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 says.

SIV

Based on its genetic sequence, the virus appears most closely related to a number of SIV strains collected recently in gorilla faecal 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.

Original source

The discovery of a gorilla virus in humans could suggest that some of these group O viruses came from gorillas, Robertson says, but it's also possible that the virus originated chimpanzees and was transmitted independently to gorillas and to humans.

"Until we do more sampling we're also guessing a little bit," Robertson concedes.

Chimps can Transmit SIV to Humans (HIV)

The discovery that chimpanzees can develop an AIDS-like illness after infection with simian immunodeficiency virus (SIV), may have implications for future AIDS research and the prevention of HIV infection.

Until now, it was thought that SIV infection in chimps did not result in disease. However, after following 94 wild chimps in Gombe Stream National Park in Tanzania for nine years, Beatrice Hahn, of the University of Alabama at Birmingham, and colleagues have shown that SIVcpz, the virus that jumped from chimps to humans as HIV-1, can and does cause an AIDS-like illness.

Over the 9 years of the study, SIVcpz infection caused an increased risk of mortality. "Up to 41 per cent in adults and 100 per cent in infants, and lower birth rates," says Hahn, "but we need longer-term follow-up to determine what proportion of infected animals develop an AIDS-like illness."

Unique opportunity
Hahn suspects that compared to HIV-infected humans, a greater proportion of SIV-infected chimps do not go on to develop fatal disease. "But this is not simple to test because chimpanzees don't just walk into clinics and give you a blood sample."

However, Hahn hopes that future research into animals which have long-term infection without developing an AIDS-like illness will yield insights that will enable us to better tackle HIV infection.

Unique Opportunity
The team believes that these findings provide a unique opportunity to compare the disease-causing mechanisms of two closely related viruses – SIVcpz and HIV-1 – in two closely related species. Such work has also already yielded information on mortality rates, prevalence and routes of spread of HIV and SIV.