SIMIAN FOAMY VIRUS ISOLATED FROM AN ACCIDENTALLY INFECTED HUMAN INDIVIDUAL

Evidence for natural foamy virus (FV) infections in humans is still la cking. However, accidental infections of humans with simian FV have be en demonstrated by serology and PCR, but all previous attempts to reco ver infectious virus in such cases have failed. Here we describe the i solation of a simian FV from peripheral blood mononuclear cells (PBMC) of a healthy animal caretaker, who acquired the virus 20 gears ago fr om an African green monkey (AGM) bite. Properties of the human isolate such as host range in cell cultures including human PBMC and ability to induce neutralizing antibodies in the primate host proved to be sim ilar to those of FV obtained from AGM. The genomic sequence of the iso late was found to be virtually identical to the proviral sequence pres ent in the host lymphocytes and related to AGM isolates but distinct f rom those of all FV isolates handled in the laboratory. For successful virus isolation, it was essential to stimulate the host lymphocytes b y phytohemagglutinin and interleukin-2 for 2 weeks prior to cocultivat ion with permissive cells. In contrast to the situation found in FV-in fected monkeys, virus isolation from the saliva of the animal caretake r was not possible, and no evidence for FV transmission to family cont acts was obtained. We conclude that, in contrast to active infection i n monkeys, FV persists in a state of latency following accidental infe ction of humans.