In 2017, Tamil Nadu, a southern state, had the second highest number of dengue cases from India. In the present study, the serotype-specific differences in the clinical manifestations and laboratory parameters among hospitalized children with dengue were investigated and molecular characterization of the circulating dengue virus (DENV) serotypes during 2017 in Tamil Nadu was performed. Eighty children with dengue-like symptoms consecutively admitted to a tertiary care hospital and positive for DENV NS1 antigen were investigated for DENV serotype utilizing a real-time reverse transcriptase based polymerase chain reaction assay. Complete envelope (E) gene sequencing of the DENV strains was performed. Seventy samples were positive for serotyping (25 DENV-1, 17 DENV-2, six DENV-3, and 22 DENV-4). DENV-4 infections were associated with elevated levels of liver enzymes; Alanine aminotransferase (P = .021) and aspartate aminotransferase (P = .001). However, none of the serotype was associated with any specific clinical features and severe dengue. Asian and American/African genotypes of DENV-1 were cocirculating. The circulating genotype was cosmopolitan for DENV-2 with multiple lineages, genotype III for DENV-3 and genotype I for DENV-4. Unique mutations were present in the 2017 DENV-4 isolates. The present study suggests the association of DENV-4 with elevated liver enzymes in children hospitalized for dengue. Further, the study reports the genetic diversity of DENV circulating in Tamil Nadu during 2017. The study calls for continuous monitoring of the circulating serotypes and genotypes at regional level in India which might result in a region wise database useful in predicting future outbreaks.
Keywords: alanine aminotransferase; aspartate aminotransferase; dengue; genotypes; serotypes; severe dengue.
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