Determination of the Proportion of Dengue Serotypes by RT-PCR and Correlation of Its Severity as per Recent WHO Classification at a Tertiary Care Hospital, Bhavnagar

Abstract Background: Dengue fever, caused by the dengue virus (DENV), is a major global health concern, particularly in tropical and subtropical regions. India, being hyperendemic, has witnessed an increasing burden of dengue, with outbreaks peaking post-monsoon. This study aimed to identify the prevalent dengue serotype and assess its correlation with disease severity based on the WHO 2009 classification. Aim: To identify the prevalent dengue serotype and to correlate its severity of serotype clinically according to recent WHO classification. Materials and Methods: This prospective study was conducted at the Viral Diagnostic and Research Laboratory, Department of Microbiology, Government Medical College, Bhavnagar, from September 2022 to August 2023. A total of 148 patients with suspected dengue fever, confirmed by NS1 antigen and/or IgM ELISA, were included. Dengue serotyping was performed using RT-PCR. Clinical severity was categorized into dengue without warning signs, dengue with warning signs, and severe dengue per WHO guidelines. Results: Out of 148 suspected cases, 87 (58%) were RT-PCR-confirmed for dengue. The most affected age group was 16-30 years (49%), with peak incidence in October. DENV-2 was the predominant serotype (57 cases, 65%), followed by DENV-4 (18 cases, 20%), DENV-1 (4 cases, 5%), co-infection of DENV-2 and DENV-4 (7 cases, 9%), and a rare triple infection (DENV-1, DENV-2, and DENV-4) in 1 case (1%). Clinical severity analysis revealed that DENV-2 was associated with more severe cases (12 with warning signs, 9 with severe dengue), followed by DENV-4 (3 with warning signs, 1 severe case). Conclusion: DENV-2 was the predominant serotype and strongly associated with severe cases, reinforcing its clinical significance. Continuous serotype surveillance, vector control, and RT-PCR-based diagnostic integration into routine dengue surveillance are critical for disease management and vaccine strategies.