Distribution Of Aedes Albopictus And Aedes Japonicus In Urban And Peri-Urban Environments In The Basque Country Of Northern Spain

Invasive mosquitoes’ distribution has increased in recent decades throughout Europe. In 2014 Aedes albopictus was identified for the first time in the Basque Country (northern Spain) and in 2020 Aedes japonicus was detected in the three Basque provinces. This study aimed to evaluate the association of invasive mosquito presence with factors related to urbanization. In 2021, a total of 568 ovitraps were deployed in 113 sampling sites located in 45 municipalities, and tablets (wooden sticks) were fortnightly replaced and examined for Aedes spp. eggs detection from June to November. A selection of positive tablets with eggs compatible with Aedes spp. were hatched, and emerged adult mosquitoes were morphologically or molecularly identified. Aedes albopictus and Ae. japonicus showed to be widespread in the studied area, and co-occurrence of both species was observed in eight municipalities. The presence of Ae. albopictus was associated with municipalities with higher population density. Ae. japonicus was associated with peri-urban areas and municipalities with lower population density. According to our results, surveillance programs should be designed for different urbanization gradients.