AIDS is the biggest public health threat for a generation. To date there have been a few hundred victims in Britain, but experts predict there will soon be many thousands. AIDS will affect men, women and children and, unless a cure is found, all those who get it will rapidly die. Doctors and scientists are desperately searching for a drug or a vaccine to knock out the virus. Will prevention - safer sex - prove better than a cure? Can alternative medicine bring hope to AIDS victims?