An association between encephalomyocarditis virus infection and reproductive failure in pigs.

An outbreak of reproductive failure, characterised by mummified foetuses and stillbirths, was investigated in an intensive piggery. Six foetuses that died towards the end of gestation had multifocal myocardial necrosis and encephalomyocarditis virus was recovered from 4 of these foetuses but not from 6 mummified foetuses. There was also a significant increase in failure of conception or early embryonic deaths in sows mated at the same time as sows which produced affected litters.