Experimental Encephalomyocarditis Virus Infection in Pigs

A field isolate of Encephalomyocarditis (EMC) virus was inoculated intravenously into 8 pigs. Four animals died at post inoculation day (PID) 2, the remaining being sacrificed at PID 5, 7, 11 and 15. Two control, in-contact pigs were sacrificed at PID 19. Virus was isolated from leucocytes and nasal swabs until PID 4, from rectal swabs until PID 2 and, in the pigs found dead at PID 2, from several organs. EMC virus was further isolated from brain and spleen of the pig sacrificed at PID 7. One of the 2 control pigs became infected: virus was isolated from nasal swabs at days 6 and 7 and from leucocytes at day 4 of the experiment. Serum-neutralizing (SN) antibody was detected in the injected pigs starting from PID 4; two days later, it was also revealed in the infected, in-contact control. To our knowledge, this is the first report of an experimental transmission of EMC virus infection in pigs by contact exposure.