Genomic characterization and evolutionary analysis of dengue virus from mosquitoes in Telangana, India.

Background & Objectives: Entomological surveillance for mosquito-borne viruses is vital for monitoring disease transmission and vector control programs. The vector control program is reliant not only on vector density but also on the timely detection of mosquito-borne infections. In the present study, we conducted an entomological surveillance in different locations of Hyderabad, Telangana, India during 2017-2018 and the collected mosquitoes were screened for dengue virus.

Methods: Reverse transcriptase polymerase chain reaction (RT-PCR) was used for the identification and serotyping of the dengue virus. Bioinformatics analysis was performed using Mega 6.0 software. Followed by phylogenetic analysis, which was based on CprM structural genome sequence, was performed by using the Maximum-Likelihood method.

Results: The TaqMan RT-PCR assay was used to analyze the serotypes of 25 pools of Aedes mosquitoes and found that all four serotypes are circulating in Telangana. DENV1 (50%) was the most commonly detected serotype followed by DENV2 (16.6%), DENV3 (25%), and DENV4 (8.3%). Moreover, DENV1 has the highest MIR (16 per 1000 mosquitoes) compared with DENV2, 3, and 4. The CprM structural gene sequence was used for phylogenetic analysis, revealing that all four strains have a close relationship with strains isolated from India, Pakistan, China and Thailand. Similarly, two variations in amino acid sequence DENV1 at position 43 (K-R) and 86 (S-T) and a single mutation DENV2 at 111 amino acid position were observed.

Interpretation & Conclusion: The results of the study provide an in-depth transmission dynamic of the dengue virus and persistence of this emerging pathogen in Telangana, India that needs appropriate prevention programs.