Invasion of the Dengue Vector Aedes albopictus in the Port City of Takoradi, Southwestern Ghana

In mid-2023, Aedes albopictus , a key dengue vector, was unexpectedly identified during Anopheles surveillance in Takoradi, southwestern Ghana. Ae. albopictus is not known to be breeding in Ghana until this encounter. By mid-2024, the Ghana Health Service reported several outbreaks of dengue for the first time, with confirmed cases in several regions, including Takoradi. This study investigated the bionomics and insecticide susceptibility of Ae. albopictus through larval and adult surveys near the initial detection sites, including the seaport. Among 2,666 Aedes larvae collected, car tyres were the most productive habitat (66.4%). Ae. aegypti (87.2%) were the most abundant vector, followed by Ae. albopictus (12.2%). Ae. albopictus was fully susceptible to pyrethroids and pirimiphos-methyl, while Ae. aegypti was resistant to pyrethroids. PBO synergist assays restored susceptibility in Ae. aegypti . kdr mutations were detected in both species: Ae. albopictus had low frequencies of F1534C (0.18), V410L (0.02), V1016I (0.00) whilst Ae. aegypti showed high F1534C (0.72), V1016I (0.50), and V410L (0.06). These findings provide essential baseline data for public health action and necessitate the urgent need for enhanced vector surveillance and resistance monitoring in Ghana.