Pathogenesis of Fatal Encephalomyocarditis (EMC) Virus Infections in Albino Rats

Abstract

Encephalomyocarditis (EMC) virus can cause fatal infections in albino rats as shown in experiments with 3 different strains of the agent, 2 isolated in Africa and one in Florida. Susceptibility to intraperitoneal inoculation ranged from 100% in suckling to 10% in full grown adult rats. Suckling rats had a generalized infection with viremia and growth of virus in skeletal and heart muscles as well as in brain tissue. Histologic studies showed that both myocarditis and encephalitis were present. In older rats which became infected, virus apparently multiplied only in the brain. Studies of previous investigators had indicated that albino rats experience only inapparent infections following inoculation with EMC virus. In present experiments, however, 4 different strains of albino rats have proved equally susceptible to infection characterized by paralysis and death.