Laboratory surveillance of viral meningitis by examination of cerebrospinal fluid in Cape Town, 1981-9.

Nine years accumulated laboratory data derived from the culture of the cerebrospinal fluid of 11,360 aseptic meningitis cases were retrospectively reviewed to establish the epidemiology of viral meningitis in Cape Town. Virus was isolated from 3406 of the cases (91% enteroviruses and 9% mumps). Five major summer viral meningitis episodes were documented: two of echovirus 4 (706 and 445 cases), echovirus 9 (223), coxsackie A9 (104) and one of unidentified enterovirus (324 cases--probably echo 9). Although coxsackie B was endemic, clusters of one or other type were dominant at any one time. Mumps was endemic. Sixty-two percent of all viral cases were < 5 years old. The median ages of 4 and 5 years in echoviruses 9 and 4 (the epidemic strains) contrasted with that of 1 year in coxsackie B (with many cases < 3 months old). Mumps peaked at 3-4 years of age. Males dominated overall, particularly in mumps.