Vol. 9, Issue 3 (2020)

Author(s):
Smita, Sanjay Shakya, Anil Patyal, Choodamani Chandrakar and Ankit Shukla

Abstract:
JE is a vector (mosquito) borne viral zoonotic disease, caused by flavivirus belonging to family Flaviviridae. The virus has five genotypes which mainly affect the central nervous system. Previously genotype III was the most widely distributed genotype in Asian countries including India with the prototype of Nakayama strain but in recent years genotype I is largely replacing genotype III (Karthikeyan et al., 2017).The World Health Organization (WHO) has attributed JE to be the most important cause of mosquito borne viral encephalitis in endemic Asian countries especially in the pediatric age group (0–14 years), where 75% of the cases occur. An estimated 67,900 cases of JE are reported annually, with approximately 13,600–20,400 deaths, while 2 billion people are at risk located in 24 WHO member countries. India and China experience 95% of the reported disease burden of JE. Two thirds of the at risk population for JE is in China and India only (Rustagi et al., 2019). Japanese encephalitis (JE) is a major threat with case fatality rate up to 30%.It causes severe neuro-psychiatric sequelae that necessitates lifelong support amounting towards considerable socioeconomic burden. The natural maintenance reservoir for JE virus are birds of the family Ardeidae (herons and egrets). Pigs act as important amplifiers of the virus producing high viraemias which infect mosquito vectors (OIE, 2019). The infection causes a spectrum of clinical illness that begins with flu-like symptoms, neck stiffness, disorientation, coma, seizures, spastic paralysis and eventually death.The ideal method for laboratory confirmation of JEV is testing cerebrospinal fluid (CSF) or serum for JEV-specific IgM antibody (Kulkarni et al., 2018). Currently, there is no cure for JEV, and treatment is mainly supportive. National Vector Borne Disease Control Programme (NVBDCP), Govt. of India, works towards prevention and control of six important vector borne diseases and Japanese encephalitis is among one of those diseases. The effectiveness of vector control strategies is limited due to the complex eco-epidemiology of the virus. Vaccination is the most effective means of prevention, where JEV is a major public health problem.