Persistence of passively acquired antibodies to hemagglutinating encephalomyelitis virus in swine.

The persistence of passively acquired antibodies to hemagglutinating encephalomyelitis virus (HEV) was determined in 4 pigs in each of the litters of 10 sows. At time of delivery by the sows, the colostrum and serum samples (from the 10 sows) had hemagglutination-inhibiting antibodies to HEV. All of the pigs also had hemagglutination-inhibiting antibodies to HEV at 2 days of age. The level of circulating antibodies to HEV decreased at a nonlinear rate and persisted for about 4 to 18 (mean 10.5) weeks in the circulation of pigs. All 40 pigs were seronegative at 20 weeks of age.