Simian immunodeficiency virus
Simian immunodeficiency virus (SIV), also known as African Green Monkey virus, is a retrovirus able to infect at least 33 species of African primates. SIV has been present in monkeys and apes for at least 32,000 years, probably longer. Strains from two of these primate species have crossed the barriers into humans resulting in HIV-2 and HIV-1. Contraction involves contact with the blood of chimps that are often hunted for bushmeat in Africa.
SIV infections appear in many cases to be non-pathogenic. Studies have proven that these infections do not cause any disease in animals. However, recent studies in chimpanzees experience an AIDS-like illness similar to HIV-1 infected humans.
Some captive monkeys were reported to have immunodeficiency similar to human AIDS. SIV was isolated in 1985 from some of these animals. SIV discovery was made shortly after HIV-1 had been isolated as the cause of AIDS and led to the discovery of HIV-2 strains in West Africa. HIV-2 was more similar to SIV strains than it was to HIV-1. SHIV was created for research by combining parts of HIV and SIV genomes.