Isolation of encephalomyocarditis virus among stillborn and post-weaning pigs in Quebec

Encephalomyocarditis (EMC) virus was isolated from aborted fetuses and lungs of suckling pigs from three Quebec pig farms that experienced outbreaks of reproductive failure in sows and respiratory problems in suckling and post-weaning piglets. Multifocal interstitial pneumonia and mild non-suppurative myocarditis and meningoencephalitis were the more significant histopathological lesions observed in piglets. Vero cells were found to be more sensitive than BHK-21 cells and pig cell lines for primary isolation of EMC virus. The Quebec EMC virus isolates were highly virulent for mice and were antigenically related to reference strain of EMC virus as demonstrated by indirect immunofluorescence, seroneutralization and Western immunoblotting. Specific virus neutralization antibody titers up to 1:12,800 were detected in samples of thoracic or abdominal fluids of the aborted fetuses.