An international team of researchers has identified a wild chimpanzee infected with simian immunodeficiency virus (SIVcpz). The identification of the infected animal strengthens the case that wild chimpanzees are the reservoir of SIVcpz, which researchers believe is a relative of the human immunodeficiency virus (HIV). Analysis of the SIVcpz strain found in the Gombe chimpanzee revealed that it was different from any previously known SIVcpz or HIV-1 strains. According to scientists, the lack of resemblance with other strains of the virus found in the wild animal rules out east African chimpanzees as the natural source of human HIV.