One hundred and eighty-one cynomolgus monkeys born and raised at Tsukuba Primate Center for Medical Science (TPC) were serologically examined for the presence of antibodies against simian virus 5, measles virus and herpes simplex virus. All of them were virtually free from infections with these viruses, whereas wild-originated breeders kept at TPC were highly positive for these antibodies. These results can be regarded as demonstrating that an indoor breeding system such as TPC's is useful and valuable for producing nonhuman primates of good quality being completely free from those viral infections.
