Japanese encephalitis (JE) might be more common in Indonesia than previously thought. In a study published today in the open access journal BMC Medicine (http://www.biomedcentral.com/bmcmed/), researchers analyzed the incidence rate of JE, a potentially deadly disease transmitted by mosquito, in children living on the Indonesian island of Bali.
Researchers at the International Vaccine Institute in South Korea and their Indonesian collaborators found an incidence rate of 8.2 per 100,000 in children under 10 years of age on the resort island. 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 programs for JE are needed in Bali," said Prof. Zhi-yi Xu, an IVI senior scientist who co-authored the study.
The study in Bali was part of IVI's JE Vaccine Program, which is supported by the Children's Vaccine Program at the Program for Appropriate Program in Health (PATH) and the Korea International Cooperation Agency (KOICA). The program, which started in 2001, seeks to determine JE disease burden and the efficacy of various vaccines against the disease in Indonesia, Vietnam, and China.
The IVI researchers, in collaboration with Dr. Komang Kari from Udyana University School of Medicine in Bali and other institutions in Indonesia and Thailand, studied 239 Balinese children who reported to health centers or clinics with symptoms similar to those of JE between July 2001 and December 2003.
The study confirmed that 86 out of the 239 children had JE and that four other 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 older than 10 years. Of the children with confirmed JE, 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.
JE is a viral infection caused by a mosquito-borne virus, and is common in most rural areas inhabited by Asia's poorest populations. Approximately 35,000 cases are reported to the World Health Organization (WHO) annually. More than 99% of all cases of JE reported around the world occur in Asia.
Vaccines are the most effective public- health tool to protect populations at risk and have been effective in controlling JE in some Asian countries, including South Korea, where the IVI is based. However, other countries afflicted with the disease have been slow to pursue the use of vaccines, which can cost up to US100 dollars per person.
The IVI aims to speed up the use of vaccines against JE and other "neglected diseases" as the world's only international organization devoted exclusively to research and development of new vaccines for the poor. It conducts translational research programs in 21 countries in Asia, Africa and Latin America, as well as laboratory research programs at its headquarters in Seoul.