Acute encephalitis and bacterial meningitis in children in Aichi Prefecture (1984-1993)

A survey was performed of acute encephalitis and bacterial meningitis in infancy and childhood from 1984 to 1993 using a questionnaire directed to departments of pediatrics in large hospitals in Aichi prefecture. The case records for 391 patients with acute encephalitis including related diseases and 328 patients with bacterial meningitis were obtained from 63 hospitals. Of 391 patients with acute encephalitis, 224 were male and 167 were female. Of 328 patients with bacterial meningitis, 200 were male and 128 were female. Sex ratio were 1.3, 1.6 respectively. Of the patients, 52.4% of encephalitis and 84.8% of meningitis were under 4 years of age and 0 year olds made up 53.7% of the latter. The causes of these diseases were confirmed in 38.7% and 82.9% of the encephalitis and meningitis patients, respectively, etiologically. In encephalitis, rubella virus was the most frequent with 29 cases, followed by measles virus (27 cases), herpes simplex virus (24) and varicella-zostervirus (19). In meningitis H. influenzae (95 cases), S. pneumoniae (56), Group B streptococcus (41) and E. coli (27) were frequently diagnosed. These diseases showed respective patterns of age distribution and clinical course, and moreover, the increases in their onset were clearly related to the prevalence of causal infections. Therefore, the results of this study should be utilized in the development of administrative measures for prevention of these diseases.