writes in about a Norwegian team who believe they have an explanation about the unique distribution of HIV in Africa. "While around the world a vast majority of AIDS victims are men, Africa has long been the glaring exception: Nearly 60 percent are women. And while there are many theories, no one has been able to prove one. In a modest public health clinic behind a gas station here in South Africa's rural KwaZulu/Natal Province, a team of Norwegian infectious disease specialists think they may have found a new explanation. It is far too soon to say whether they are right. But even skeptics say the explanation is biologically plausible. And if it is proved correct, a low-cost solution has the potential to prevent thousands of infections every year. The Norwegian team believes that African women are more vulnerable to H.I.V. because of a chronic, undiagnosed parasitic disease: genital schistosomiasis (pronounced shis-to-so-MY-a-sis), often nicknamed 'schisto.' The disease, also known as bilharzia and snail fever, is caused by parasitic worms picked up in infested river water. It is marked by fragile sores in the far reaches of the vaginal canal that may serve as entry points for H.I.V., the virus that causes AIDS. Dr. Eyrun F. Kjetland, who leads the Otimati team, says that it is more common than syphilis or herpes, which can also open the way for H.I.V."