%0 Journal Article
%T Evolution of New Variants/Mutants of JE Virus, Its Effect on Neurovirulence, Antigenicity, Host Immune Responses and Disease Transmission in Endemic Areas
%A Ravi Kant Upadhyay
%J Journal of Viruses
%D 2014
%R 10.1155/2014/516904
%X This paper highlights various reasons of evolution of new mutants/variants of JE virus and its effects on neurovirulence, antigenicity, host immune responses, and disease transmission in endemic areas. Virus is reorganizing its genome by making sequence alterations, single site mutations, cluster specific reversions, and amino acid substitutions in neutralizing antigenic sites mainly in N¡ä glycosylation sites and epitopic regions of S and E proteins. Virus is regularly changing gene order, gene density by making substitution point mutations in important structural genes which make virus envelope proteins. Further, JE virus acquiring new genetic variations and adaptabilities through genetic recombination of wild strains with vaccine strains and assimilating new lethal genes that lead to emergence of molecular variants/mutants. These newly emerged JE virus genotypes have attained the ability to escape the immune defense and show wider resistance against vaccines and therapeutic agents. Thus new strains did significant elevation in the level of neurovirulence, antigenicity and pathogenesis. It is causing very high mortalities in various infant groups and imposing lifelong irreversible disorders in survivors and showing a regular trend of emergence and reemergence in endemic areas. The present review article emphasizes methods to suppress virus replication, reversion of neurovirulence, attenuation and an utmost need of more potential vaccines against cross reactive heterologous genotypes of JE virus to control disease transmission and mortalities occurring in endemic areas. 1. Introduction Flavivirus, Japanese encephalitis (JE) virus, is the leading cause of acute viral encephalitis syndrome of central nervous system and mortalities of patients throughout Asia [1]. Though a large number of flaviviruses, such as Dengue virus and West Nile Virus Murray Valley encephalitis virus, are capable of giving rise to encephalitis, but, among all flaviviruses, JEV is proved highly dreadful because it severely invade many tissues and cells to establish an acute epidemic encephalitis syndrome in patients. Virus invasion generates severe inflammatory responses inside host, which later on spreads throughout the brain and results in necrosis of neurons and causes perivesicular cuffing, thrombosis, and variable degree of meningitis. Virus imposes very high neurovirulence and hemorrhage that give rise multiple disorders and lethality in various infant groups. Moreover, severity of infection with flaviviruses usually results into long lasting immunity and virus antigens boost
%U http://www.hindawi.com/journals/jvi/2014/516904/