Reverse transcription polymerase chain reaction (RT-PCR) was used for the detection of classical swine fever virus (CSFV) in blood and tissue samples of field cases and experimentally inoculated pigs. The distribution of CSFV in different organ samples showed some discrepancies in infected pigs. Four weaner pigs were inoculated with C-strain vaccine virus, then samples of spleen, tonsil, lung, mesenteric lymph node, kidney and brain were collected after slaughter and tested for E2 and NS5B genes using one-step RT-PCR and nested RT-PCR. Using the same method, 12 field cases were simultaneously studied. A discrepancy of CSFV in different samples was found upon detecting the target gene. The most reliable diagnostic organs were spleen and tonsil, and the nested RT-PCR assay provided a highly sensitive and specific method with comparable performance to the one-step RT-PCR assay.
