[Epidemic of aseptic meningitis with echovirus type 7 in Gifu prefecture in 1986].

During the period from April to November in 1986, an epidemic of aseptic meningitis occurred in Gifu prefecture. Epidemiological, virological and serological investigations were performed. Cases involved ranged from 0 to 30 years of age, and 84.2% of them were under 7 years of age. Seven types of enteroviruses were isolated from 136 of 190 cases (71.6%), and echovirus type 7 was recovered from 121 cases (88.9%). With the cross neutralizing test between the prototype and isolated strains in 1986 of echovirus type 7, a remarkable antigenic variation could not be found. In the serological studies, the positive rates of neutralizing antibodies to echovirus type 7 in 1985, was lower than those in 1975. During the past 18 years before the 1986, echovirus type 7 was not isolated in Gifu prefecture, but in the serological studies, it was confirmed that the sporadic infection with echovirus type 7 had occurred in Gifu prefecture.