Serotype distribution and association of dengue viral load with clinical severity: A serotype-specific qRT-PCR study

Hasnain Raza; Abdul Razaq; Nazakat Shafiq; Shahiryar Ahmad; Tahira Mushtaq

doi:10.63626/t9s62d45

Authors

Hasnain Raza Author
Abdul Razaq Author
Nazakat Shafiq Author
Shahiryar Ahmad Author
Tahira Mushtaq Author

DOI:

https://doi.org/10.63626/t9s62d45

Keywords:

Dengue virus, Serotype, DENV-2, qRT-PCR

Abstract

Background: Dengue fever is a viral infection caused by arbovirus; an enveloped single standard RNA virus belongs to the family Flaviviridae. Since last two years, onward from 2023, changes in climate, urbanization and distribution pattern of biological vectors leads to increase transmission of dengue virus. In recent outbreak, all four serotype of dengue virus DENV-1, DENV-2, DENV-3 and DENV-4 have been detected in Pakistan.

Methods: The current prospective cross-sectional study was conducted from March 2025 to October 2025 at Allama Iqbal Teaching Hospital Dera Ghazi khan. A total of 278 dengue suspect patients were enrolled in the study and were using serotype specific quantitative real-time polymerase chain reaction (qRT-PCR).

Results: The mean age of the participant was 35 years ranging from 15 to 76 years and there was a male predominance (64.4%). The results of current study showed that among these 278 tested samples, 28 were positive for dengue virus as confirmed by qRT-PCR. Among the 28 confirmed dengue cases, DENV-2 was most prevalent serotype 16/28, followed by DENV-1 8/28, DENV-3 3/28 and DENV-4 was found to be least prevalent (1/28). Seasonal distribution analysis showed highest positivity in the months of August and September with 7 and 10 positive cases respectively. The results of present study also showed that the mean Ct value for DENV-1, DENV-2, DENV-3 and DENV-4 were 27.8 ± 4.6, 23.9 ±3.5, 28.1 ±5.0 and 28.4 ±4.4 respectively. It was observed that individuals infected with serotype DENV-2 had significantly lower Ct value which indicated higher viral load. Patients with higher viral load showed severe signs and symptoms as well.

Conclusion: DENV-2 serotype was found to be the most prevalent serotype during 2025 dengue outbreak followed by DENV-1, DENV-3 and DENV-4 in studied region. Higher viral load was directly proportional to severity of disease particularly in patient infected with DENV-2.