Molecular Epidemiology of Dengue Virus Serotypes and Their Association With Disease Severity

Background: Dengue is an important mosquito-borne viral infection with considerable variation in circulating serotypes and disease severity. Molecular surveillance helps identify predominant serotypes and their association with clinical outcomes. This study evaluated the circulating dengue virus serotypes and their relationship with disease severity in patients from Central India. The aim & objective is to investigate the molecular epidemiology of circulating dengue virus serotypes, identify DENV-1 to DENV-4 by RT-PCR, determine their demographic and clinical distribution, assess their association with disease severity, and generate data to strengthen dengue surveillance and public health interventions. Materials and Methods: A cross-sectional observational study was conducted among 290 clinically suspected dengue patients at a tertiary care hospital in Indore, Madhya Pradesh, from January 2023 to January 2026. Serum samples were screened using the SD BIOLINE™ Dengue Duo Rapid Test. Dengue viral RNA was detected and serotyped using the RealStar® Dengue Type RT-PCR Kit 1.0. Clinical manifestations and hematological parameters were recorded, and multivariate logistic regression was used to identify factors associated with severe dengue. Results: Rapid testing was positive in 61 (21.0%) patients, while real-time RT-PCR confirmed dengue infection in 67 (23.1%). Among RT-PCR-positive cases, DENV-2 was predominant (31, 46.3%), followed by DENV-3 (18, 26.9%), DENV-1 (14, 20.9%), and DENV-4 (2, 3.0%); mixed-serotype infection occurred in 2 (3.0%) cases. DENV-2 infection was significantly associated with severe dengue (OR 2.91, 95% CI: 1.28–6.62; p=0.009). Platelet count <50,000/µL was the strongest predictor (OR 4.72, 95% CI: 2.01–11.08; p<0.001), followed by bleeding manifestations (OR 3.18; p=0.011) and abdominal pain (OR 2.37; p=0.039). Vomiting, abdominal pain, bleeding, and hypotension were significantly associated with serotype. Conclusion: DENV-2 was the predominant circulating serotype and showed a significant association with severe dengue. Molecular serotyping combined with clinical and hematological assessment may improve recognition of patients at risk of severe disease.