Finding unveiled: Culex thalassius (Diptera: Culicidae), a new mosquito species emerges in the Cabo Verde archipelago.

Mosquito-borne diseases can pose significant burdens. In many countries, they pose a risk to national economies and the well-being of humans and animals. To mitigate this, mosquito surveillance is crucial to assess the real and potential transmission of mosquito-borne diseases. Between 2020 and 2023, mosquito larvae were collected from both indoor and outdoor breeding sites in urban and rural areas of 4 municipalities of Santiago and Boavista Islands in Cabo Verde. Mosquitoes were identified morphologically and by polymerase chain reaction-based techniques that targeted the mitochondrial cytochrome C oxidase subunit I sequence. During this period, 6,825 breeding sites were assessed, and of 8,094 mosquito specimens screened, 194 specimens of Culex thalassius were identified for the first time in the country in 4 municipalities of Santiago and Boavista Islands. This new finding highlights the importance of including entomological surveillance in health systems. Although this species has only been detected on a few islands, it is important to continuously monitor it to determine its distribution, spread/dispersal, density, and potential involvement in pathogen transmission.