Seroepidemiology of dengue and chikungunya viruses in Chabahar city, southwestern Iran-2025

Abstract Dengue and chikungunya viruses (DENV, CHIKV), transmitted by Aedes mosquitoes, pose significant public health challenges in tropical and sub-tropical regions. This study investigated the seroprevalence of DENV and CHIKV in Chabahar city, an area in which Aedes aegypti has been established and local transmission of DENV reported since 2023. From January to February 2025, a total of 650 serum samples were collected from the catchment area of eight health centers in the city and tested for DENV and CHIKV IgG using ELISA kits. The overall ELISA‑defined DENV IgG seropositivity was 14.3% (95% CI 11.7–17.3%) and for CHIKV was 0.9% (95% CI 0.4–2.1%). The highest prevalence of DENV was observed in the urban areas of Zibashahr and urban-2 Districts (25%), and the lowest in Kambel Soleiman (4%). Men had a significantly higher DENV seroprevalence (17% vs. 10.8% in women, p = 0.012), and seroprevalence decreased with increasing education level ( p = 0.021). Older age was associated with increased DENV seropositivity ( p = 0.040). Occupation was not significantly associated with DENV seropositivity. No significant association was found between mosquito bite reports and seropositivity. These findings provide evidence of ELISA‑defined DENV IgG seropositivity in the general population of Chabahar, suggesting previous exposure to DENV. The high seropositivity in certain districts highlights the need for strengthened surveillance and targeted vector control measures in high risk groups and areas with high Aedes mosquito density.