"This demonstrates that HIV evolution is an ongoing process," Dr. David Robertson, an AIDS researcher and frequent contributor to Nature Medicine, told the magazine.
The HIV-1 strain, which is the main source of human infections, with 33 million cases worldwide, came from a chimpanzee virus. It was discovered in the 1980s, but is believed to have jumped to humans who came into contact with infected bush meat, the BBC reported.
French doctors who were treating the 62-year-old Cameroonian woman living in Paris said they initially spotted some discrepancies in routine viral load tests. Further analysis of the HIV strain showed more similarity to Simian Immunodeficiency Virus than to HIV from humans.
The doctors said before moving to Paris, she lived in a semi-urban part of Cameroon and had no contact with bush meat, meaning she may have caught the virus from someone else carrying that particular strain. Researchers said expect to find more similar cases.