Congenital tremor in pigs farrowed from sows given hog cholera virus during pregnancy.

At different stages of gestation, 3 groups of pregnant sows were inoculated with a strain of hog cholera virus (HCV). After the infection, clinical signs of hog cholera were not observed in the sows. Pigs from the sows infected on day 22 or 43 of gestation showed varying degrees of muscular tremor, ataxia, splayleg, and suckling inability. Of the pigs with tremor, 83% had cerebellar hypoplasia. Surviving pigs demonstrated persistent viral infection and continued to shed HCV, but did not have antibodies to HCV. Sows infected at 72 days of gestation farrowed numerous mummified and stillborn pigs. Signs of tremor were not seen in any pigs from these sows.