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.