Experimental infection of pregnant sows with porcine enteroviruses.

In a series of experiments, SMEDI A--porcine enterovirus serotype 8--was given by intrauterine route to pregnant gilts at intervals between gestation days 0 and 30, and SMEDI C-porcine enterovirus serotype 1--was given to pregnant gilts at intervals between gestation days 30 and 41 to 43. Antibodies were detected in fetuses from groups inoculated at gestation days 30 and 41 to 43, whereas virus was isolated from fetuses only from groups inoculated at gestation days 41 to 43. When inoculated directly into the uterus, embryonic or fetal infection with these viruses was observed regardless of the preinoculation serologic status of the gilts, indicating that maternal antibody had no effect on embryonic or fetal infections after the virus was in the uterus. Intranasal inoculation of SMEDI C caused embryonic or fetal infections in seronegative gilts but not in gilts that carried specific antibody to SMEDI C at the time of exposure. Antibodies in gilts that were seropositive at time of inoculation probably neutralized the virus before it could reach the uterus and thus prevented embryo or fetal infections.