Detection of bovine polyomavirus contamination in fetal bovine sera and modified live viral vaccines using polymerase chain reaction.

A nested polymerase chain reaction (PCR) assay has been developed for the detection of bovine polyomavirus (BPyV) DNA. The assay has been used to screen commercial lots of fetal bovine serum and modified live veterinary vaccines for the presence of the agent. A PCR product of the expected size was detected after the first round of PCR for eight out of 20 serum lots, but in none of the 14 vaccines tested. The subsequent nested assay revealed that four more serum lots were positive for BPyV DNA, as well as two vaccine lots. When hybridized with a labelled probe, blots of the PCR products from vaccines revealed that in one of the two positive samples a specific product was present after the first PCR at a level not detectable in gel electrophoresis. Nested PCR appears to be a useful tool for the detection of low level contamination with BPyV DNA of products used in, and derived from cell culture.