Sir, Japanese encephalitis outbreaks occur frequently in 14 Asian countries with about 3060 million people at risk of infection (1). JE is a of major public health concern due to its high epidemic potential, high case fatality and neuropsychiatric sequelae among survivors. The estimated global burden of JE was 709000 disability–adjusted life years (DALYs) lost in 2003 (2). Epidemiology of JE is complex due to involvement of several vertebrate and invertebrate hosts. JEV is transmitted naturally between ardeid birds and pigs by mosquitoes species mostly belonging to Culex genera. The Culex vishnui subgroup mosquitoes comprising Cx. tritaeniorhynchus, Cx. vishnui and Cx. pseudovishnui have been implicated as major vectors of JE in India (3). JE epidemics have been frequently encountered in several States of India. Occurrence of JE epidemics is a regular feature in Gorakhpur, Uttar Pradesh (UP), since the first major JE epidemic in 1978 (4). A total of 2320 suspected cases and 528 deaths of JE from Uttar Pradesh mostly from Gorakhpur were reported in 2006 (Source: Website of National Vector Borne Disease Control Programme, New Delhi). Thus, serological and entomological observations were made to confirm the aetiology of a focal outbreak of JE in rural areas of Gorakhpur Division, UP in 2006.