Influence of dose and route on transmission of encephalomyocarditis virus to swine.

The susceptibility of swine to infection with encephalomyocarditis virus (EMCV) was assessed. Transmission of EMCV in a single exposure by gavage or intranasal routes was highly dose dependent. In a direct comparison, animals were exposed to EMCV by gavage, intranasal, intramuscular, intratracheal, or transdermal routes. A higher proportion of animals exposed by transdermal (5/5), intratracheal (5/5), or intramuscular (5/5) routes than those exposed by intranasal (2/5) or gavage (3/5) routes became infected. The large quantity of virus required to infect animals intranasally or orally suggests that transmission by these routes may not occur routinely in the field. Transmission of EMCV by wound contamination (transdermally) has not been reported previously. Although EMCV was recovered from rectal, external genitalia, and pharyngeal swabs, there was no evidence of pig-to-pig transmission of EMCV from experimentally infected animals to comingled sentinels.