EPIDEMIOLOGIC CHARACTERIZATION OF A PESTI VIRUS ISOLATE FROM A VIREMIC PIG OUT OF A MIXED PIG CATTLE HERD

A pestivirus isolated from a healthy pig out of a mixed pig-cattle hol ding was identified by use of monoclonal antibodies as a porcine virus related or identical to bovine Viral diarrhoea (BVD) virus. About 7% of the pigs of this herd showed neutralizing antibodies (nab) against BVD and Border Disease (BD) Virus and against the homologeous porcine- nonclassical swine fever (GSF) pestivirus isolate 10421/Han94. The nab titres against this virus were clearly higher than against CSF virus strain Alfort/187. Amongst the cattle kept in the farm no BVD viraemic animal was detected. About 13 % of them showed nab to BVD virus with higher titres against the BVD virus strain NADL than against the porci ne pestivirus virus isolate 10421/Han94. There was no indication of a BVD virus transmission from the cattle to the pigs within this herd. T he problem of misinterpretation of non-CSF virus isolation from pigs i s discussed. The necessity of identifying pestiviruses of porcine orig in by use of species-specific monoclonal antibodies is stressed in ord er to prevent erroneous declarations of CSF outbreaks.