AIDS may not be a new disease. The HIV virus probably long possessed its own niche in the African rain forests. The opening up of isolated areas to economic exploitation, population migrations, travel and tourism may have flushed it out into a defenceless world. Some experts consider that it may not be a coincidence that AIDS appeared in Africa at the same time that the World Health Organisation was eradicating smallpox. ‘During the 1970s members of the WHO were vaccinating young people in central Africa with live smallpox vaccine, re-using needles 40 to 60 times. Live vaccines directly provoke the immune system, and can awaken sleeping giants such as viruses'.