In the present review article epidemiology of Japanese encephalitis, disease incidences and its control measures have been described in detail. Among important reasons of JE outbreak are registered demographic clustering, ecological imbalance, and insecticide resistance in target mosquito species, poor economy, lack of socio cultural environment and timely therapeutics. Other complex reasons are negative anthropogenic activities like mixed agro-pig farming practices, paddy farming and sanitation. Water contamination led to the spillovers of the virus from its wildlife reservoir into pig population as well as other vertebrate hosts. This article also explains emergence of new mutant variants/ new genotypes /ecological strains of JE virus and its spread in endemic to non-endemic areas. Due to re-circulation of virus among various hosts and insect vectors, disease is causing vey high mortality and morbidity in rural and sub-urban endemic areas. In addition, presence of revertants in overlapping generations of virus joins and re-organizes distanced epidemiology in the area. It has led to induction of high sero-conversion rate in patients. Present review aims to explain all the reasons of JE epidemics, and justify need of proper surveillance, rapid diagnosis, long term safer immunization, vector control and socio-clinical management of JE infection. This article emphasized an urgent need of potential immunization, implementation of planning to improve economic, environmental and socio-cultural conditions. It also strongly indicates need of regular surveillance and immunization of JE affected population to maintain high therapeutic standards to control JE epidemics.

JE virus, endemic diseases, epidemiology, disease transmission vector, vertebrate hosts, immunization, eco-17 climate