Molecular Characterization and Serotype Distribution of Dengue Virus in Bengaluru Rural

Introduction

Dengue is one of the largest prevailing mosquito-borne viral infections, with an increasing load in India due to fast development and low regulation of vectors. Dengue virus circulates as four distinct serotypes (DENV-1 to DENV-4) with significant genetic variability influencing disease epidemiology. Identification of circulating serotypes and their genotypes is essential to understand viral evolution and transmission patterns.

Objectives

This study had the following objectives:

1. To detect Dengue serotypes DENV-1, DENV-2, DENV-3, and DENV-4 among positive RT-PCR samples.
2. To sequence genotypes among the serotypes detected.

Methods

ELISA-positive dengue samples (n = 380) collected from clinically suspected patients between 2021 and 2023 were subjected to real-time RT-PCR for detection of viral RNA. Positive samples were further analyzed for serotype identification and selected samples among different serotypes for gene sequencing. Phylogenetic analysis was performed to determine genotypic distribution.

Results

Out of 380 samples, 275 (75.9%) were RT-PCR positive. Serotyping revealed DENV-2 as the predominant serotype (56.7%), followed by DENV-1 (36.7%) and DENV-3 (6.5%), while DENV-4 was not detected. Phylogenetic analysis showed that DENV-1 belonged to Genotype III and DENV-2 to the Cosmopolitan Genotype IV, indicating circulation of multiple genetic lineages

Conclusion

The study demonstrates the predominance of DENV-2 along with co-circulation of other serotypes in Bengaluru Rural. The presence of distinct genotypes highlights ongoing viral evolution. Continuous molecular surveillance is crucial for tracking dengue dynamics and supporting effective control strategies.