REVIEW ARTICLE

Abstract

CURRENT opinion is divided as to the role of the encephalomyocarditis (EMC) group of viruses in human disease. In the serologic survey of Tarahumara Indians reported elsewhere in this issue it has been shown that antibody neutralizing significant amounts (namely, 20, 80, 1000, and 6000 LD50, respectively) of the AMS strain of EMC virus was found in 4 of the 56 serum specimens studied. This finding serves to focus attention again on the scattered reports suggesting the EMC virus as an etiologic agent in human disease. History of the Discovery of EMC Viruses Jungeblut and Sanders isolated from cotton rats inoculated with Yale-SK strain of poliomyelitis virus, a virus different from that which they had inoculated. They designated this new agent "Columbia-SK." Later Jungeblut and Dalldorf isolated an agent they called MM-virus from hamsters inoculated with central nervous system (CNS) tissue of a fatal case of undiagnosed paralysis suspected of being poliomyelitis. Many workers have assumed that these first isolations were of viruses latent in the laboratory rodents. Helwig and Schmidt obtained encephalomyocarditis (EMC) virus from a captive chimpanzee with myocarditis and hydrothorax in Florida; and Dick, Best, Haddow, and Smithburn obtained so-called Mengo encephalomyelitis virus in Uganda from a paralyzed rhesus monkey, later from mosquitoes (Taeniorrhynchus fuscopennatus), and from a wild mongoose caught near the monkey compound in Entebbe, Uganda. Accidental infection of a laboratory worker in Entebbe with Mengo virus demonstrated the pathogenicity of this agent for man. The worker developed an encephalitic illness and the virus was isolated from his serum.