The origin of HIV has been found in wild chimpanzees living in southern Cameroon, researchers report.

It is thought that people hunting chimpanzees first contracted the virus – and that cases were first seen in Kinshasa, in the Democratic Republic of Congo – the nearest urban area – in 1930.

Scientists believe the rareness of cases – and the fact that symptoms of Aids differ significantly between individuals – explains why it was another 50 years before the virus was named.

[Read](http://news.bbc.co.uk/2/hi/health/5012268.stm) (BBC)