Isolation of foamy viruses from baboon (Papio cynocephalus) tissues.

Fourty per cent of baboon kidney cell cultures were found to contain foamy virus contaminants regardless of sex of the animal, source or time of year. The older the animal, however, the higher the incidence. Fifty percent of placentas examined contained foamy virus, with first and second trimester specimens more likely to be positive. Foamy virus isolates from baboon lymphocytes were also more frequent as the age of the animal increased. Freezing and thawing these lymphocytes prevented foamy virus isolation. The foamy virus isolates were identified as types 1, 2, or 3.