Outbreak of Aseptic Meningitis due to ECHO-9 in Northern Kyushu Island inthe Summer of 1997

Abstract

An outbreak of aseptic meningitis caused by echovirus type 9 (ECHO-9) occurred between June and August 1997 in the Chikugo area, Fukuoka, Japan. Clinical manifestations and laboratory data of 317 children with aseptic meningitis were analyzed. The age of the patients ranged from 1 month to 12 years with the highest incidence in 4 years old children. The male: female ratio was 2.0:1.0. Symptoms of the meningitis included fever (100%), headache (89.5%) and nausea and/or vomiting (85.6%). Skin rash was not frequent (2.2%) in contrast to previous reports of ECHO 9 infections. The number of white blood cells (WBC) in cerebrospinal fluid (CSF) ranged from 10 to 3, 493 cells/, u I (median; 412 cells/μl). The neutrophils were more than 50% of the WBC in CSF in one-fourth of the patients at diagnosis. Enteroviruses were identified from CSF utilizing virus culture and enterovirus-specific RT-PCR, and ECHO-9 infection was determined by antibody titer of paired sera. Finally 44 patients were diagnosed virologically or serologicaily as aseptic meningitis caused by ECHO-9. Sequence analysis revealed that two strains of ECHO-9 isolated from CSF in this epidemic were closely related to ECHO-9 virulent strain Barty.