A warming welcome? Belgium's increasing suitability for Aedes albopictus

Abstract

Aedes albopictus, commonly known as the Asian tiger mosquito, is an invasive species of significant public health concern due to its ability to transmit dengue, chikungunya, and Zika viruses. Since arriving in Europe in the late 1970s, this mosquito species has progressively expanded its range, with Belgium marking an important step in its northward spread. The increasing frequency of its introduction raises the urgent question of whether Ae. albopictus could become permanently present in the country. This study investigates the potential for the establishment of Ae. albopictus populations in Belgium using a mechanistic model and assessing the likelihood of successful establishment based on simulated introduction events. Our results indicate that the probability of establishment is highest in Flanders, particularly under scenarios of early and multiple introductions during the summer months, even though the interannual climatic variability still plays a major role in establishment success. The establishment of Ae. albopictus in Belgium would introduce new epidemiological risks, as the species could facilitate the transmission of non-native viruses during particularly warm summers. While the transmission windows may remain limited compared to Mediterranean regions, continued introductions and climate change could expand these periods, increasing the likelihood of local outbreaks.

Keywords: Aedes albopictus; Europe; Mechanistic model dynamAedes.

Fig. 1

The introduction locations (blue) and overwintering observations (red) of Aedes albopictus in Belgium over the period 2000–2024. Inset: the year of observed overwintering at the five locations (districts). Country borders: black. Main routes: light grey

Fig. 2

Percentage of successful Aedes albopictus introductions from 2018 to 2021 under scenarios involving single or multiple introduction events, starting with either 500 or 1000 eggs on June 30 or July 15 of each year. Values represent the average percentage of successful introductions over the final 30 days of each simulation. Lines represent the three regions of Belgium: Flanders (North), Wallonia (South) and Brussels (within Flanders)