22 September 2005

Japanese encephalitis in India and Nepal

An outbreak of Japanese encephalitis (JE) has been occurring in northern India and Nepal since July 2005.

The World Health Organization Regional Office for South East Asia (SEARO) has reported a total of 3,551 cases with 764 deaths (case fatality rate of 22%) in 30 districts of Uttar Pradesh as of 18 September 2005 [1]. The adjoining state of Bihar has reported 238 cases and 58 deaths (CFR 24%) during the same period. The Indian government has intensified control measures.

In Nepal as of 15 September 2005, a total of 1,540 cases with 259 deaths (CFR 17%) have been reported. Most cases have occurred in the western, mid-western and far-western regions of the country. 

JE is transmitted by the bite of the Culex spp mosquito and is endemic in many parts of India.  Thousands of cases are reported each year [2]. Peak transmission season (May to October) in northern India occurs during and just after the monsoon season when major outbreaks coincide with heavy rains and flooding. Case numbers in the region are reported to be higher this year than in previous years.

The risk of JE for travellers who stay for short periods in urban areas is low.  All travellers to endemic areas should be advised to practice insect bite avoidance methods, particularly between dusk and dawn, when the mosquito vector is most active.

Vaccination is not usually recommended for short visits to urban areas.  Vaccine should be considered for those intending to stay for long periods in rural endemic regions during the main transmission season; for those whose planned activities will increase their risk; and for all long-term expatriates. 

References

1. World Health Organization, Regional Office for South East Asia (SEARO). Japanese Encephalitis in India and Nepal, 2005 [online] [cited 21 September 2005]. Available at www.searo.who.int/en/section10/section392_10316.htm

2. Kabilan L, Rajendran R, Arunachalam N, Ramesh S, Srinivasan S, Philip Samuel P, Dash AP. Japanese encephalitis in India: An overview. Indian J Pediatr 2004;71:609.  Available at: http://www.ijppediatricsindia.org/article.asp?issn=0019-5456;year=2004;volume=71;issue=7;spage=609;epage=615;

aulast=Kabilan

Link

NaTHNaC Japanese encephalitis information sheet http://www.NaTHNaC.org/pro/factsheets/japanese_enc.htm