Attention has been directed in recent years toward the study of the ECHO viruses in relation to the production of disease in the human central nervous system (CNS). An evaluation of the clinical and epidemiologic potentialities of these viruses is best obtained from the study of an epidemic caused predominantly by one virus serotype, where the study is supported by virologic data. This report presents the results of a study of an epidemic of aseptic meningitis due to ECHO virus Type 4.
The ECHO viruses have been classified, with the polioviruses and the Coxsackie viruses, into the enterovirus group,1 which currently consists of 61 serotypes. All enteroviruses multiply within the human alimentary tract, and they demonstrate fundamental similarities in physical, biochemical, and epidemiologic characteristics. Each serotype must be studied separately because of the diverse potential for disease production demonstrated by individual serotypes. Disease, when it occurs, may range from