The University of Nebraska-Lincoln reports evidence that supports the theory of the origins of HIV, and in particular, confirms that forms of HIV can cross species from chimps to humans.

Share on Pinterest SIV strains, which have not previously been found in humans, have the potential to cause another HIV-like infection.

HIV attacks the immune system by destroying cells that fight disease and infection. There is no cure for HIV, but with medical care and treatments, most people with the virus can live a long and productive life.

More than 1.2 million people in the United States are estimated to have HIV, and 1 in 8 are unaware that they have the virus.

The origin of HIV has been the cause of much debate among scientists. The most commonly accepted theory identifies a type of chimpanzee in Central or West Africa as the source of HIV infection in humans.

Scientists suggest that the chimpanzee form of the immunodeficiency virus, called simian immunodeficiency virus (SIV), was potentially transmitted to humans and mutated into HIV.

The transmission from chimpanzees to humans was thought to occur when humans hunted chimps for meat in the early 1900s and came into contact with their blood.

In previous research, some scientists discovered a strain of SIV in a chimpanzee that was almost identical to HIV in humans, which validated the view that chimps were the source of HIV-1 and, furthermore, that the virus had crossed species.

The new study, led by senior author Qingsheng Li, associate professor of biological sciences and member of the Nebraska Center for Virology, supports the hypothesis of HIV originating from SIV.

The research team reports the first in-vivo evidence that strains of chimpanzee-carried SIVs can infect human cells. The strains involved are ancestors of HIV-1 M – the strain of HIV responsible for the global HIV pandemic – and another strain found in Cameroon.