[Epidemic of aseptic meningitis with echovirus type 18 in Gifu Prefecture in 1988].

On one hundred thirty seven cases with aseptic meningitis and 36 cases except aseptic meningitis in 1988, virological and serological investigations were performed. Cases with aseptic meningitis ranged from 0 to 15 years old age, and 90.5% of them were under 8 years of age. Seven types of enteroviruses and one unidentified strain were isolated from 58 of the 137 cases (42.3%), and echovirus type 18 was recovered from 46 cases (79.3%). Echovirus type 18 was isolated also from 16 cases with acute febrile illness and exanthem etc. With the cross neutralizing test between the prototype and isolated strains in 1988 of echovirus type 18, a slight antigenic variation could be found. In the serological studies in 1989, the positive rate of neutralizing antibody to echovirus type 18, was raised remarkably in children under 8 years old.