| a retrospective serological survey of the encephalomyocarditis virus among pigs in chiba prefecture, japan. | one thousand two hundred and forty pigs' sera collected from 1975 to 1992 on 240 farms in chiba prefecture were subjected to a neutralization test for the encephalomyocarditis (emc) virus. seven (23.3%) of 30 pigs in 1975 had neutralizing antibodies against the emc virus. the antibody positive rates each year ranged from 16.7% (1976) to 56.3% (1981). the differences of antibody positive rates between districts were not great after 1985. these serological results suggested that the emc virus infe ... | 1995 | 8519923 |