The asian tiger mosquito aedes albopictus in Switzerland : biology surveillance and control

The Asian tiger mosquito Aedes albopictus originates from the tropical and subtropical regions of Southeast Asia, from the islands of the Western Pacific and the Indian Ocean. Over the last century, A. albopictus has spread globally. This species is able to form dormant egg stages that survive long periods of dryness and also low temperatures. The eggs are passively dispersed, primarily through the trade with used tyres and plant cuttings. The tiger mosquito is a proven vector for many arboviruses, most notably dengue and chikungunya, with recent outbreaks also in continental Europe. In 2003, A. albopictus was spotted for the first time in Switzerland, in the southernmost part of the Canton of Ticino. Since then the local authorities have continued its surveillance and control. The control programme mainly includes larval source reduction alongside larvicidal applications. Despite these efforts, mosquito densities have increased over the last decade, casting doubts on the effectiveness of such larval control programmes. The Italian communities just across the border lack such a surveillance and intervention programme providing the possibility to compare an intervention versus a non-intervention area side by side.
The overall aim of this work was to study the biology of the A. albopictus population in Switzerland to better understand the risk of local vector-borne disease transmissions, by reviewing the effect of existing control measures in the Canton of Ticino. Four specific objectives were pursued in this PhD: (i) to compare the spatial and temporal distribution of A. albopictus in Ticino (intervention) with its distribution in the neighbouring Italian communities (non-intervention) just across the national border, evaluating the impact of the Ticino control programme, (ii) to assess the insecticide susceptibility status of the A. albopictus population in Swiss-Italian border region, (iii) to investigate host preferences of A. albopictus, (iv) to assess the vector competence of the local A. albopictus population for dengue virus (DENV) transmission und local conditions.