History, Virology, Pathogenesis, Epidemiology, and Laboratory Diagnosis of Dengue Virus: A Focused Review.

Dengue virus (DENV) is a mosquito-borne flavivirus with four antigenically distinct serotypes and represents a leading cause of acute febrile illness in tropical and subtropical regions worldwide. This focused review summarizes the historical evolution of dengue disease descriptions, virus discovery, vectors and transmission dynamics, viral structure, mechanisms of pathogenesis-including antibody-dependent enhancement (ADE) and non-structural protein-1 (NS1)-mediated endothelial dysfunction-clinical classification, current epidemiology with emphasis on India, and laboratory diagnostic approaches. We highlight persistent gaps in molecular surveillance, particularly incomplete genotype and lineage characterization in routine hospital-based studies, and discuss emerging diagnostic and surveillance tools such as real-time reverse transcription polymerase chain reaction (RT-PCR), NS1 antigen detection, isothermal amplification, plaque reduction neutralization tests (PRNT), and genomic sequencing. The review concludes by outlining priorities for strengthening surveillance, diagnostics, and research to improve clinical management, vaccine policy, and public health response in endemic and peri-urban/rural settings.