Detection and diagnosis of parapoxvirus by the polymerase chain reaction.

The genus Parapoxvirus includes four members, bovine papular stomatitis virus (BPSV), pseudocowpox virus (PCPV), orf virus (ORFV) and parapoxvirus of red deer in New Zealand (PVNZ). A set of primers for polymerase chain reaction (PCR) was designed to detect viral DNA from cells infected with each of the four parapoxviruses. The set of primers resulted in the amplification of appropriately sized products from cells infected with BPSV, PCPV, ORFV and PVNZ, respectively. The PCR method was applied for the detection of seven field isolates of parapoxvirus from cattle, sheep and free-ranging wild Japanese serows. The expected size of DNA was amplified from cells infected with each of the seven isolates. No specific PCR products were detected from vaccinia virus-, fowlpox virus- and mock-infected cells. Moreover, by a semi-nested PCR with an inner primer and Southern blot analysis, viral DNA was detected from lesions of clinically affected cattle, sheep and Japanese serows. These results suggested that the PCR method used in this study was specific for the detection of parapoxviruses and thus useful for diagnosis of parapoxvirus infections, especially in discrimination from diseases with similar clinical symptoms.