[An epidemic of aseptic meningitis caused by echoviruses in Fukuoka Prefecture during April 1997 to August 1998].

An epidemic of aseptic meningitis in Fukuoka Prefecture during April 1997 to August 1998 was studied to determine the serotype of viruses isolated in Fukuoka Prefecture. In Fukuoka Prefecture, bimodal peaks were seen in July and December 1997. Monthly changes of reported aseptic meningitis patients and period of virus isolation revealed that epidemics of the earlier part in 1997 was caused by echovirus 9 (E 9) and the latter part due to echovirus 30 (E 30). E 9 was isolated mainly in Chikugo Area from June to October 1997 but, E 30 was isolated all in areas of Fukuoka Prefecture. Isolation of E 30 continued after January 1998 in Fukuoka Prefecture. Isolation of echovirus 18 started in June 1998. The main serotypes of isolates are changing. The E 30 isolates are serotyped by neutralization with the aid of antiserum pools for enterovirus type differentiation, but serotyping was difficult with commercially available antiserum. The result of neutralization tests with standard serum and an immune albino rabbit serum prepared in our laboratory with the E 30 isolates indicated that the isolates in Fukuoka Prefecture was an antigenic variant.