A review of Japanese-B virus encephalitis in Malaysia

JE is neither classified as an entity in the Malaysian Medical records system nor is it a notifiable disease but is grouped under the broad umbrella of viral encephalitis. There is no centralised program by the Ministry of Health specially for JE surveillance and control. JE is endemic, occurs sporadically throughout the country all year round. Asymptomatic inapparent infections have been found to be more frequent than acute clinical encephalitis cases, judging from results of previous serosurveys (Pond et al., 1954). JE vaccination has never been tried in Malaysia. In a relative sense, JEV infection unlike dengue virus infection, does not appear to be much of a problem in Malaysia. Perhaps, the laboratory confirmed cases represent only a small proportion of the total hospitalised cases that actually occurred. The reasons may be that these cases could not be confirmed by laboratory tests due to improper timing or failure to obtain the second serum specimen, or failure to perform lumbar puncture on patient's refusal. Attempts to improve the case detection rate of JE in Malaysia should be made namely, by increasing clinical index of suspicion, instituting better specimen collection procedures and by adopting rapid diagnostic tests.