Molecular characterization of circulating dengue virus serotypes and genotypes from central India

BACKGROUND: Dengue fever is a vector borne viral disease common in tropical and subtropical climates. The present study reports the comprehensive molecular characterization of dengue virus (DENV) serotypes and genotypes from the central part of the Indian state, Madhya Pradesh, during 2023. METHODS: In the retrospective study, 2442 suspected DENV cases were collected from January to December 2023 and were further analyzed using non-structural protein 1 (NS1) and IgM ELISA to determine seroprevalence. Samples collected within ≤5 d of onset of fever were included for serotyping and genotyping. Phylogenetic analysis was done using partial envelope (E) gene sequences. RESULTS: Of 2442 samples, 231 were DENV positive, including 13 NS1 positive and 218 IgM ELISA positive cases. Among these, 61 samples (13 NS1 positive and 48 IgM positive within ≤5 d of fever) were subjected to PCR. 16 (26.2%) samples tested positive for DENV by PCR and were sequenced, of which 12 cases belonged to DENV-2, while four were DENV-1. Phylogenetic analysis showed that DENV-2 (cosmopolitan genotype, lineage 4) was predominant, followed by DENV-1 (genotype III [GIII]). CONCLUSIONS: These findings demonstrate that DENV-2 cosmopolitan lineage 4, and DENV-1 GIII in central part of India during 2023.