An outbreak of St. Louis encephalitis (SLE) occurred in St. Louis County in late summer 1966. Thirteen serologically confirmed or presumptive cases were observed. The most intense SLE-virus activity was in University City, a suburban community of St. Louis, Missouri. A serologic survey conducted 3 months after the outbreak indicated a low level of antibody prevalence among the residents of University City. Most persons with SLE antibody were in the older age groups. A serologic survey conducted in a nearby community that had no reported encephalitis cases revealed antibody patterns similar to those observed in University City. Four cases of central-nervous-system infection that were investigated were related to Coxsackie virus A9 and two to herpes simplex.
Formerly Epidemic Intelligence Service Officer, National Communicable Disease Center, assigned to the Virus Disease Section, Kansas City, Kansas, Present address: University of Minnesota Hospital, Minneapolis, Minnesota.
Formerly Chief, Virus Disease Section, Kansas City, Kansas. Present address: Chief, Zoonoses Section, EIP, Fort Collins, Colorado.
Deputy Health Commissioner, Public Health Laboratory Services, City of St. Louis Division of Health, St. Louis, Missouri.
Director, Ecological Investigations Program, National Communicable Disease Center, 2002 West 39th Street, Kansas City, Kansas 66103. Please address requests for reprints to Dr. Chin.