Genetic and Phylogenetic Characterization of Dengue Virus among Clinically Suspected Patients in Eastern India

AIM: Dengue is an acute systemic viral disease well known globally in both endemic and epidemic transmission cycles. Main aim is to study serotypes/genotypes and lineages of dengue virus (DENV) are associated with more severe outbreaks. Many reports from India have shown an association between change in DENV genotype/lineage and magnitude of the outbreak and disease severity. Study Design. It is a hospital based cross sectional study. Place and Duration of Study: Molecular Biology laboratory in department of Microbiology, Indira Gandhi Institute of Medical Science and duration study from January2021 to January 2023. Material and Methods: This cross- sectional study was aimed to investigate the circulating DENV serotypes and genotypes in Bihar during year 2021-2023. For genetic characterization of prevalent serotypes, real-time reverse transcription polymerase chain reaction assay was used. Representative samples were sequenced for the envelope (E) gene. Results: All four prevalent serotypes, DENV-1, DENV-2, DENV-3 and DENV-4 were found to be circulating in Bihar with dominance of DENV-2. Mixed infection cases of DENV-2 with DENV-3 and DENV-1 with DENV-2 were also seen. Phylogenetic analysis based on C-prM gene revealed DENV-1 sequences to be 92% similar with Vietnam genotype I (2003) strain, DENV-2 isolates clustered with genotype IV of North India strains, Haryana (1996), Delhi (1996) and Jammu (1993) with 95%, 94% and 94% sequence similarity respectively. DENV-3 isolate was more closely related to genotype III of Indian origin (2003), Gwalior and Delhi with 98% and 99% sequence similarity respectively. Conclusion: With this background data, molecular monitoring of viruses circulating in the locality provides baseline data on the circulating serotypes/ genotypes of dengue virus (DENV). So this monitoring and early detection of changes in the circulation pattern may help in the prediction of DENV outbreaks and can augment disease control efforts.