2007 Volume 60 Issue 2 Pages 125-130
Pig sera collected from breeding sows in one farm in Hokkaido prefecture were diagnosed as antibody-positive with a commercial ELISA of classical swine fever (CSF) in 2002 and 2003. However, an on-site inspection and virological examination concluded that an outbreak of CSF in this pig farm was negative. As a result of further ongoing inspections, antibody-positive sera with this ELISA were confirmed again from the sows, which had no history of vaccination against CSF. To specify the causative virus that had infected these pigs, the neutralization titers of the sera against classical swine fever virus (CSFV) were compared with those against bovine viral diarrhea viruses (BVDVs) and border disease virus (BDV), since these viruses are classified in the samepestivirusgenus. As a result, neutralization titers against BVDV NOSE strain were markedly higher than those against CSFV, BDV and other BVDV strains. From the data and from epidemiological investigations revealing indirect contact between a pig and a cow, it is concluded that the pigs on this farm were infected with BVDV. This report concludes that infections of pigs with BVDV and BDV should be considered important cases for the laboratory diagnosis of CSF.
