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Envelope protein gene based molecular characterization of Japanese encephalitis virus clinical isolates from West Bengal, India: a comparative approach with respect to SA14-14-2 live attenuated vaccine strain.
BMC Infect Dis. 2013 Aug 08; 13:368.BI

Abstract

BACKGROUND

Increasing virulence of Japanese encephalitis virus (JEV), a mosquito-borne zoonotic pathogen is of grave concern because it causes a neurotrophic killer disease Japanese Encephalitis (JE) which, in turn, is responsible globally for viral acute encephalitis syndrome (AES). Despite the availability of vaccine, JE/AES cases and deaths have become regular features in the different rural districts of West Bengal (WB) state, India, indicating either the partial coverage of vaccine or the emergence of new strain of JEV. Therefore, a study was undertaken to characterize and compare the complete envelope (E) protein gene based molecular changes/patterns of JEVs circulating in WB.

METHODS

Total of 98 AES case-patients' samples were tested to detect the presence of JEV specific immunoglobulin M (IgM) antibody by Mac-ELISA method. Only JEV IgM negative samples with a history of ≤3 days' illness were screened for virus isolation and RT-PCR. E gene sequences of JEV isolates were subjected to molecular phylogeny and immunoinformatics analysis.

RESULTS

Present study confirmed JEV etiology in 39.7% and 29.1% of patients presenting ≤15 days' febrile illness, as determined by Mac-ELISA and RT-PCR respectively. Phylogenetic analysis based on complete E gene sequences of JEV isolates showed the co-circulation of JEV genotype I (GI) with genotype III (GIII). This study also demonstrated that isolate-specific crucial amino acid substitutions were closely related to neurovirulence/neuroinvasiveness of JE. On the basis of immunoinformatics analysis, some substitutions were predicted to disrupt T-cell epitope immunogenicity/antigenicity that might largely influence the outcome of vaccine derived from JEV GIII SA14-14-2 strain and this has been observed in a previously vaccinated boy with mild JE/AES due to JEV GI infection.

CONCLUSIONS

Based on molecular evolutionary and bioinformatic approaches, we report evolution of JEV at a local level. Such naturally occurring evolution is likely to affect the disease profile and the vaccine efficacy to protect against JEV GI may demand careful evaluation.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23927571

Citation

Sarkar, Arindam, et al. "Envelope Protein Gene Based Molecular Characterization of Japanese Encephalitis Virus Clinical Isolates From West Bengal, India: a Comparative Approach With Respect to SA14-14-2 Live Attenuated Vaccine Strain." BMC Infectious Diseases, vol. 13, 2013, p. 368.
Sarkar A, Banik A, Pathak BK, et al. Envelope protein gene based molecular characterization of Japanese encephalitis virus clinical isolates from West Bengal, India: a comparative approach with respect to SA14-14-2 live attenuated vaccine strain. BMC Infect Dis. 2013;13:368.
Sarkar, A., Banik, A., Pathak, B. K., Mukhopadhyay, S. K., & Chatterjee, S. (2013). Envelope protein gene based molecular characterization of Japanese encephalitis virus clinical isolates from West Bengal, India: a comparative approach with respect to SA14-14-2 live attenuated vaccine strain. BMC Infectious Diseases, 13, 368. https://doi.org/10.1186/1471-2334-13-368
Sarkar A, et al. Envelope Protein Gene Based Molecular Characterization of Japanese Encephalitis Virus Clinical Isolates From West Bengal, India: a Comparative Approach With Respect to SA14-14-2 Live Attenuated Vaccine Strain. BMC Infect Dis. 2013 Aug 8;13:368. PubMed PMID: 23927571.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Envelope protein gene based molecular characterization of Japanese encephalitis virus clinical isolates from West Bengal, India: a comparative approach with respect to SA14-14-2 live attenuated vaccine strain. AU - Sarkar,Arindam, AU - Banik,Avishek, AU - Pathak,Bani K, AU - Mukhopadhyay,Subhra K, AU - Chatterjee,Shyamalendu, Y1 - 2013/08/08/ PY - 2013/03/22/received PY - 2013/07/30/accepted PY - 2013/8/10/entrez PY - 2013/8/10/pubmed PY - 2014/11/14/medline SP - 368 EP - 368 JF - BMC infectious diseases JO - BMC Infect Dis VL - 13 N2 - BACKGROUND: Increasing virulence of Japanese encephalitis virus (JEV), a mosquito-borne zoonotic pathogen is of grave concern because it causes a neurotrophic killer disease Japanese Encephalitis (JE) which, in turn, is responsible globally for viral acute encephalitis syndrome (AES). Despite the availability of vaccine, JE/AES cases and deaths have become regular features in the different rural districts of West Bengal (WB) state, India, indicating either the partial coverage of vaccine or the emergence of new strain of JEV. Therefore, a study was undertaken to characterize and compare the complete envelope (E) protein gene based molecular changes/patterns of JEVs circulating in WB. METHODS: Total of 98 AES case-patients' samples were tested to detect the presence of JEV specific immunoglobulin M (IgM) antibody by Mac-ELISA method. Only JEV IgM negative samples with a history of ≤3 days' illness were screened for virus isolation and RT-PCR. E gene sequences of JEV isolates were subjected to molecular phylogeny and immunoinformatics analysis. RESULTS: Present study confirmed JEV etiology in 39.7% and 29.1% of patients presenting ≤15 days' febrile illness, as determined by Mac-ELISA and RT-PCR respectively. Phylogenetic analysis based on complete E gene sequences of JEV isolates showed the co-circulation of JEV genotype I (GI) with genotype III (GIII). This study also demonstrated that isolate-specific crucial amino acid substitutions were closely related to neurovirulence/neuroinvasiveness of JE. On the basis of immunoinformatics analysis, some substitutions were predicted to disrupt T-cell epitope immunogenicity/antigenicity that might largely influence the outcome of vaccine derived from JEV GIII SA14-14-2 strain and this has been observed in a previously vaccinated boy with mild JE/AES due to JEV GI infection. CONCLUSIONS: Based on molecular evolutionary and bioinformatic approaches, we report evolution of JEV at a local level. Such naturally occurring evolution is likely to affect the disease profile and the vaccine efficacy to protect against JEV GI may demand careful evaluation. SN - 1471-2334 UR - https://www.unboundmedicine.com/medline/citation/23927571/Envelope_protein_gene_based_molecular_characterization_of_Japanese_encephalitis_virus_clinical_isolates_from_West_Bengal_India:_a_comparative_approach_with_respect_to_SA14_14_2_live_attenuated_vaccine_strain_ L2 - https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-13-368 DB - PRIME DP - Unbound Medicine ER -