French researchers have isolated a new strain of the AIDS virus in West Africa that appears to have close genetic links to a version that infects non-human primates such as chimpanzees. It's a reminder, they said, of how genetically flexible and cunning the human immuno-deficiency virus can be.The new strain so far has been found only in one patient, a 40-year-old woman in Cameroon who died of AIDS in 1995.