Search

Objectives: We estimate the effectiveness of Japanese encephalitis (JE) SA 14-14-2 live-attenuated vaccination single dose campaign among children aged 1-15 years in India during 2006-07., Methods: Acute encephalitis syndrome (AES) cases hospitalized following vaccination campaigns during the years 2006-08 were investigated retrospectively. The laboratory-confirmed JE cases were detected from the surveillance laboratories based on anti-JE IgM antibody by ELISA or viral RNA detection by RT-PCR in sera or cerebrospinal fluid. Consent was sought from parents or guardians. Four community controls were chosen randomly per case during house-to-house survey employing individual matching on age, gender and residence during the risk period. Vaccination history was enquired from the child's guardian and verified from vaccination card at home or records at health centre. Conditional logistic regression was conducted on matched case-control sets., Results: We studied 149 cases and matched 596 controls. Vaccination effectiveness was 43.8% (95% CI, 1.9-67.8) based on vaccination card or record. However, effectiveness was 72.2% (95% CI, 56.2-82.4) based on parental history or card/record. Vaccination effectiveness in Assam state was higher than in Uttar Pradesh state., Conclusions: We concluded that the single subcutaneous dose of SA 14-14-2 JE vaccine provided moderate effectiveness in Indian children., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Japanese encephalitis (JE) is a serious public health concern in most of Asia. The disease is caused by JE virus (JEV), a flavivirus transmitted by Culex mosquitoes. Several vaccines have been developed to control JE in endemic areas as well as to protect travelers and military personnel who visit or are commissioned from non-endemic to endemic areas. The vaccines include inactivated vaccines produced in mouse brain or cell cultures, live attenuated vaccines, and a chimeric vaccine based on the live attenuated yellow fever virus 17D vaccine strain. All the marketed vaccines belong to the JEV genotype III, but have been shown to be efficacious against other genotypes and strains, with varying degrees of cross-neutralization, albeit at levels deemed to be protective. The protective responses have been shown to last three or more years, depending on the type of vaccine and the number of doses. This review presents a brief account of the different JE vaccines, their immunogenicity and protective ability, and the impact of JE vaccines in reducing the burden of disease in endemic countries.

Background & Objectives: Japanese encephalitis virus (JEV) infection results in acute encephalitic illness. The affinity of JEV to different regions of brain and temporal changes in viral load have not been studied. This study was conducted to describe localization of JEV to different regions of the brain at different stages of disease in a rat model of Japanese encephalitis (JE)., Methods: Twelve days old Wistar rats were inoculated intracerebrally with a dose of 3 x 10⁶ pfu/ml of JEV. After 3, 6, 10 and 20 days post-inoculation, brains were dissected out and different regions of brain (cortex, striatum, thalamus and mid brain) were taken. Motor deficit was assessed by the rota rod and JEV RNA copies were evaluated using real-time PCR assay., Results: There was a significant increase in motor deficit in rats inoculated with JEV compared to the controls. JEV RNA copies were present in all studied regions of the brain on days 3, 6 and 10 post-inoculation. Maximum number of JEV RNA copies were present in the mid brain on days 3 and 10 post-inoculation. JEV RNA copies were not detected in any of the brain regions on day 20., Interpretation & Conclusions: This study reports JEV RNA load in different brain regions of rat with higher affinity of JEV virus to thalamus and mid brain compared to other regions.

Clinical specimens from an encephalitis outbreak in the Lakhimpur area of Uttar Pradesh, India, were investigated for identification and characterization of the etiologic agent. IgM capture ELISA showed recent Japanese encephalitis virus (JEV) infection. JEV isolation was attempted from white blood cells (WBCs) separated from blood clots of 12 patients (9 IgM positive and 3 negative) by serial co-culturing with phytohemagglutinin P-stimulated peripheral blood mononuclear leukocytes (PBMCs) obtained from pre-screened JEV sero-negative healthy individuals. JEV was isolated from two IgM-positive blood clots. Isolate 014178 was detected in WBCs and in the first passage of PBMCs by ELISA and reverse transcriptase-polymerase chain reaction. Isolate 014173 was detectable only after a second passage in PBMC co-culture. Sequence analysis of 346 nt of the C-prM region showed homology with JEV strain GP78. This is the first report on isolation of JEV from patient blood clots. Our study shows that the co-cultures of PBMCs separated from patient blood clots provide an additional source for JEV isolation.