Two new retroviruses - the type of virus which causes AIDS - have jumped from non-human primates to people, a new study reveals.
The study of blood samples from nearly a thousand bushmeat hunters or handlers in Cameroon showed that at least six viruses had crossed from monkeys to the people who were exposed to freshly caught bushmeat. And two of these viruses have never been seen before in humans.
The newly discovered human T-cell lymphotropic virus 3 (HTLV-3) and HTLV-4 are closely related to the known viruses, HTLV-1 and HTLV-2. These are implicated in cancers like leukaemia and can cause inflammatory or neurological diseases.