Japanese encephalitis widespread in Bali

Japanese encephalitis might be more widespread in Indonesia than previously thought. In a study published today in the open access journal BMC Medicine, researchers analysed the incidence rate of Japanese encephalitis, a potentially lethal disease caused by a mosquito-borne virus, in children living on the Indonesian island of Bali. The researchers found an incidence rate of 8.2 per 100,000 in children less than 10 years old. They conclude that contrary to previous findings, which were probably due to inadequate surveillance, the disease is widespread in Bali. Better surveillance and the implementation of vaccination programmes for Japanese encephalitis are needed in Bali.

Komang Kari from Udyana Univeristy School of Medicine in Bali, Indonesia, and colleagues from other institutions in Bali, Korea and Thailand studied 239 Balinese children who reported to health centres or clinics with symptoms similar to those of Japanese encephalitis, between July 2001 and December 2003.

Kari et al. confirmed that 86 out of the 239 children had Japanese encephalitis and that a further four children probably had the disease – the virus was only detected in their serum and not in their cerebrospinal fluid. Of these 90 children, only one was over 10 years old. Of the children with confirmed Japanese encephalitis, nine died and 31 were left with serious neurological disability. The authors conclude that the annual incidence rate for children under 10 is 8.2 per 100,000.