DefinePK

Abstract

Background: Dengue virus (DENV) remains a significant public health threat in Pakistan, with its dynamics often driven by complex serotype circulation. This study investigated the molecular epidemiology and serotype distribution during a major dengue outbreak in District Charsadda, Khyber Pakhtunkhwa, Pakistan.
Methods: In this cross-sectional study, 1,382 suspected dengue patients were tested from 11 June 2025 to  5 Oct 2025. Serum samples were analyzed using NS1 antigen ELISA, IgM/IgG ELISA, and nested RT-PCR for confirmation and serotyping, following the Lanciotti protocol.
Results: Of the 1,382 suspected cases, 311 (22.5%) were NS1 positive, and 240 were confirmed by RT-PCR. The outbreak was characterized by a striking predominance of a single serotype, with DENV-2 accounting for 94.0% (126/134) of the serotyped cases. Demographic analysis revealed a higher infection rate in males (61.3%) and the 15-30 years age group (44.6%). Contrary to typical patterns, a significantly higher burden was observed in rural areas (58.8%) compared to urban settings. The outbreak peaked post-monsoon, with 79.2% of cases occurring in August and September. Clinically, fever (100%), body aches (94.2%), and nausea/vomiting (82.9%) were most common, with thrombocytopenia being significantly associated with Dengue Hemorrhagic Fever (DHF) (82.5% vs. 48.0%, p<0.001).
Conclusion: This study reveals an unusual pattern of near-complete DENV-2 monodominance in a Pakistani dengue outbreak, coupled with a notable rural predominance. The findings highlight a critical shift in serotype dynamics and underscore the urgent need for robust, real-time molecular surveillance to guide effective outbreak response and public health interventions in the region.
Keywords:
Dengue Virus, Molecular Epidemiology, DENV-2, Serotype Dominance, Outbreak, Pakistan, Nested PCR.
 
https://doi.org/10.5281/zenodo.17297228