Objective To estimate the annual prevalence of viral and other neurological infections at large hospitals in Japan during the period from 1989 to 1991.
Methods A nationwide questionnaire survey on the numbers of inpatients with viral and other neurological infections was sent for completion to the chiefs of Departments of Internal Medicine, Neurology and Pediatrics at all hospitals with more than 200 beds.
Results The average annual number of inpatients (and the number per 106 population) with encephalitis in large hospitals was estimated to be 2, 200±400 (17.7±13.2), while it was 32, 000±16, 000 (258±129) for meningitis, and 650±50 (5.2±0.4) for myelitis. Among the inpatients with encephalitis, meningitis, and myelitis, an unknown etiology was the most common (51.2% in encephalitis, 73.2% in meningitis, and 36.3% in myelitis), followed by a viral etiology for all three diseases.
Conclusion The first estimate was made of the annual prevalence of viral and other neurological infections and their etiology in Japan.
(Internal Medicine 39: 894-900, 2000)
The Japanese Society of Internal Medicine