Animal "orphan" enteroviruses.

Since the discovery, some ten years ago, of the pathogenic effect of polioviruses on non-nervous-tissue cells, tissue-culture methods have come to be widely used in virological research. Through these improved techniques for studying viruses, a large number of new cytopathogenic agents have been isolated from the intestinal tract of man. Many of these agents have been obtained from persons suffering from polio-like disease, but others have been isolated from apparently normal persons. The term "orphans" is used to designate those viruses which cannot definitely be associated with any recognized disease syndrome.The existence of these enteric pathogenic human orphan (ECHO) viruses, and their association with clinical disease in certain cases, stimulated interest in their animal counter-parts, which might constitute a serious threat to both human and animal health. In this paper, the author reviews the information at present available on the occurrence of the so-called "orphan" enteroviruses in monkeys, cattle, swine, and other animals in various parts of the world, and discusses the possible interrelationships of these animal viruses with each other and with the human enteroviruses.