First molecular evidence of Aedes aegypti and dengue virus in Qatar: Spatiotemporal data, 2022-2024

This study provides molecular confirmation of the presence of Aedes aegypti and the detection of dengue virus (DENV) in mosquito populations in Qatar, addressing a critical surveillance gap where previous evidence relied mainly on morphological or epidemiological data without genetic validation. From January 2022 to December 2024, adult mosquitoes were collected from one selected sampling site within each of the eight municipalities of Qatar. A total of 700 Ae. aegypti were identified morphologically. All 300 collected female Ae. aegypti were screened for DENV using real-time PCR (RT-PCR). All DENV-positive pools and six randomly selected morphologically identified female Ae. aegypti were sequenced (partial C-prM for DENV and cox1) for species identification), followed by Bayesian phylogenetic analyses and descriptive spatial-temporal assessment. Aedes aegypti was absent during 2022-2023, except for limited detections in Doha at the end of 2023. In 2024, spatial expansion was observed, extending to Al Rayyan and Al Wakrah municipalities. In 2024, Ae. aegypti accounted for 10.6% of the total mosquitoes collected and was associated with urban environments. The newly generated cox1 sequences showed 100% identity with reference sequences for Ae. aegypti and clustered with South Asian lineages. DENV RNA was detected in 5 out of 30 pooled female samples, with viral sequences closely related to isolates from Asia and East Africa. Descriptive spatial and temporal analyses revealed localized urban distribution and monthly variation in Ae. aegypti detections. These findings provide molecular evidence of Ae. aegypti and DENV presence in Qatar, suggesting a potential epidemiological shift. Strengthened intersectoral coordination and sustained surveillance are essential to assess and mitigate mosquito-borne disease risks in rapidly urbanizing settings.