St. Louis Encephalitis in Adults During the 1964 Houston Epidemic

The clinical features of St. Louis encephalitis were defined first during the epidemic in St. Louis in 1933, the earliest outbreak in which the virus was recovered and characterized.¹⁻³Since that time numerous observations of the disease have been reported from widely separated areas of the United States.⁴⁻¹²Most outbreaks have occurred in rural areas, the epidemic usually was recognized late, and patients were difficult to study since they were widely separated from each other and from modern diagnostic facilities. In most previous studies the number of serologically confirmed cases was small, preexisting illness was not documented, and the role of concurrent illnesses was not evaluated. Therefore a unique opportunity for study of this disease was provided when an outbreak of St. Louis encephalitis was recognized among patients in a teaching hospital of a university medical center. Results of such a study are the basis of this report.