Assessing the re-introduction of Aedes aegypti in Europe. Will the Yellow Fever Mosquito colonize the Old World?

Abstract

Aedes aegypti are feared invasive mosquitoes as they transmit pathogens which cause debilitating diseases in humans. Although mainland Europe has not yet witnessed re-establishment and diffusion of Ae. aegypti populations, several urban areas along coastlines represent suitable habitats for the species. In addition, European coastal areas are characterized by a high exotic species propagule pressure, due to the dense international ship traffic. Here, we applied a process-based population dynamical model to simulate both the life cycle and dispersal of Ae. aegypti at the local scale after its introduction through ship traffic. We selected five European ports along a gradient of latitude by considering both environmental conditions and the economical importance of ports: Algeciras and Barcelona in Spain; Venice and Genoa in Italy and Rotterdam in the Netherlands. The model was informed using parameters relevant for Ae. aegypti biology, fine-scale temperature time-series, urban structures and road networks. According to model results, the introduction of small quantities of Ae. aegypti eggs, from 10 to 1000, has the potential to cause species establishment, high local densities and slow initial dispersal in the two southernmost study areas, Algeciras and Barcelona, whereas Genoa may be considered only close to suitability. Barcelona had the highest simulated mosquito densities (584 females/ha), whereas Algeciras densities were never more than 32 females/ha, but remained higher during winter. The spatial spread of the species varied between a few hundred meters to 2 km/year and was affected by the structure of the road network, topography and urban sprawl along the coast in the surrounding of the port of introduction. The study areas of Genoa, Venice and Rotterdam were found not suitable for establishment of this mosquito species, however climate change could create conditions for Ae. aegypti invasion in these regions in the next decades. It is commonly accepted that targeted monitoring and early control actions are the most effective methods to hinder the establishment of invasive species in new areas. Our findings and model framework may support surveillance initiatives for those European coastal urban areas which have a known high propagule pressure and a high modelled probability of Ae. aegypti establishment. HighlightsO_LIEuropean coasts present favourable conditions for Aedes aegypti establishment C_LIO_LIWe assess the species introduction and establishment using a process-based model C_LIO_LIWe selected five ports: Algeciras, Barcelona, Venice, Genoa and Rotterdam C_LIO_LIAlgeciras and Barcelona were the most suitable areas for the species establishment C_LIO_LIClimate change could make more suitable the northernmost study areas C_LI