A NEW herpes virus may be the cause of Kaposi’s sarcoma, a cancer that affects up to a fifth of people with AIDS. Researchers in the US believe they have found the genetic "signature" of a previously unknown virus in cancerous tissue from people with KS. The discovery marks the first step in unravelling a controversy about the causes of the cancer and its links with HIV.

Until the advent of AIDS, KS was a very rare cancer found mainly in older men in the Mediterranean region and in some patients with suppressed immune systems. Then in the early 1980s, KS began to appear in gay men in the cities of the US. Doctors eventually recognised it as one of the conditions associated with AIDS. The cancer, which seems to be particularly aggressive in people with AIDS, causes disfiguring purple blotches on the skin.