Frequent detection of bovine polyomavirus in commercial batches of calf serum by using the polymerase chain reaction.

Twenty commercial batches of calf serum, obtained from several suppliers, were tested for the presence of bovine polyomavirus (BPyV) DNA and antibodies against the virus. Using polymerase chain reaction (PCR) technology, BPyV DNA was detected in 70% of the batches; no BPyV was detected in any of the negative control samples. The specificity of the amplification reactions was proven by hybridization. PCR results were confirmed by virus isolation experiments performed with five PCR-positive and five PCR-negative serum batches. The results indicate that the use of calf serum to supplement tissue culture media involves a serious risk of contaminating cell cultures with BPyV. No correlation was observed between the presence or absence of anti-BPyV immunoglobulins and the detection of BPyV-specific DNA sequences in the serum batches.