First indigenous transmission of Japanese Encephalitis in urban areas of National Capital Territory of Delhi, India

Abstract

Abstractobjective Until 2010, no Japanese encephalitis (JE) had been reported from Delhi. Upon report of four confirmed cases of JE in September 2011, detailed investigations were carried out to determine whether the cases were imported or indigenous.methods Entomological surveys were carried out and all mosquito pools were tested for the detection of JE virus by ELISA method using specific monoclonal antibody. Human blood samples from contacts of the patients were tested by IgM-captured ELISA method. Pig's blood samples were also tested for the detection of JE virus.results Culex tritaeniorhynchus, Culex vishnui and Culex pseudovishnui mosquitoes were found. In contrast to rural areas, their breeding habitats were different in the city. 19 pools were tested. JE virus was detected in two pools of Cx. tritaeniorhynchus females reared from field-collected larvae, indicating vertical transmission. One pool of Cx. vishnui was also positive. This is the first report for the detection of JE virus in mosquitoes from Delhi. JE IgM antibodies in five contacts/residents indicate recent infection. JE virus was also detected in pigs.conclusion Present analysis shows that of four reported JE cases, three were confirmed indigenous, indicating that the virus is multiplying in the city. Mapping of infected JE vector mosquitoes in the cities is required for preventive measures to contain further spread of the disease.

Biomarkers in Japanese Encephalitis: A Review

“…Further, due to demographic and cultural reasons JE is regularly spreading in non-endemic areas. Recently, indigenous transmission of JEV is also observed in urban areas [194]. It is fact that in rural areas, no JE diagnostic facilities are available to confirm the disease and in most of the cases due to lack of strong confirmatory biomarkers, patients die with out having any therapeutic treatment.…”

Japanese Encephalitis: A Brief Review on Indian Perspectives

“…JE has been reported in newer areas, signifying the spread of virus owing to altered land use patterns as well as vector adaptation. In the absence of rural travel, JEV activity was reported from New Delhi [ 31 ].…”

Risk assessment for Japanese encephalitis vaccination

“…In endemic areas, JE is predominantly a rural disease of children, 10 though peri-urban and urban transmission are also described. 11,12 Infection of man is a "dead-end" event for JEV, because in humans viraemia is too low and transient to be infectious to the mosquito vector. After natural JEV exposure only a small proportion of infections, estimated at approximately 0.1 to 1%, result in encephalitisthe vast majority are asymptomatic or result in a mild febrile illness only.…”