[Epidemiology of enteroviral meningitis in Croatia 1958-1988 with special emphasis on the great epidemic of 1988].

In 1988, there was a large outbreak of enteroviral meningitis in the Republic of Croatia and in other parts of Yugoslavia as well. A total of 4079 cases of enteroviral meningitis were registered with one fatal outcome (Mb 8.7 0/ooo). The outbreak was caused by echovirus 4. Analysis of epidemiological, virologic and ecological data for 1988, as well as for a number of previous years, showed the following: an upward morbidity trend observed from 1958 to 1979 turned to a high level stationary trend with irregular annual oscillations. A cyclic morbidity trend was noticed with peaks in 9-10 years. Seasonal peak was lower in July regularly. In 1988, age and sex distribution of the diseased persons differed from the usual picture, showing greater proportion of older age and women. The probable reason is in the long absence of echovirus 4 from the target population, resulting in low herd immunity. This caused greater proportion of older cases, among which women (mothers) had probably been more exposed to infections than men (nursing ill household members, laundry handling, etc). The epidemic years 1988 and 1979 were hot during spring and summer, at above-average level. Such climatic factors (high temperature) coupled with the sufficiently low level of herd immunity probably triggered in both examples the outbreak of enteroviral meningitis.