High seroprevalence of dengue virus infection among febrile patients in Kassala state, eastern Sudan: a cross-sectional analysis

Background: Dengue fever (DF) is a mosquito-borne viral infection with rising global incidence, posing a significant public health challenge in many tropical regions, including Sudan. Kassala State has witnessed recurring outbreaks, underscoring the need for updated epidemiological data. Objective: To assess the prevalence of recent dengue virus infection among febrile patients and explore demographic and clinical associations with seropositivity. Methodology: A cross-sectional study was conducted from January to April 2025 in Kassala State. Febrile patients were enrolled, and 3 mL blood samples were collected 4–6 days after fever onset. Serum samples were tested for anti-DENV IgM using a commercial ELISA. Data were analyzed using SPSS version 28. Results: Among 93 patients tested, 83 (89.2%) were positive for DENV IgM and 10 (10.8%) were negative. The highest positive cases occurred in the 1–5 year age group (43.3% of seropositive cases). 47/93 (50.5%) were male and 46/93 (49.5%) were female. The majority (90.3%) reported symptom duration of 3–7 days. Urban residents comprised 74.2% of the patients, with no significant association between residence (urban vs. rural) and seropositivity (P = 0.23). Reported symptoms among IgM-positive patients included fever (100%), headache (89.2%), vomiting (52.7%), bleeding (16.1%), and convulsions (10.8%). There were no statistically significant associations between DENV IgM seropositivity and age group (P = 0.075), gender (P = 0.97), or duration of symptoms (P = 0.65). Conclusion: A high rate of recent dengue infection was observed among febrile patients in Kassala State, indicating active transmission and the need for strengthened surveillance and control measures.