Summary 1. Mongooses of 2 species (Ichneumia albicauda and Mungos mungo), exposed to EMC virus either by the oral route or by parenteral inoculation, have proved to be extremely susceptible to a severe myocarditis. 2. The role which these animals may play in maintaining EMC virus in nature, either by predation on other mammals or by becoming intestinal carriers, is discussed in relation to experimental data. 3. An endoparasite commonly found in mongooses, Porocephalus armillatus, was found to contain virus when recovered from infected animals. 4. Although the effects of cardiac puncture are an important consideration in animals developing myocarditis under experimental conditions, mongooses not submitted to this procedure developed a myocarditis equal in severity to those which had been bled from the heart prior to inoculation.