Aedes Albopictus Restistance Status And Population Dynamics Across The Swiss-Italian Border

Abstract:
Aedes albopictus is a vector for over 20 viruses, including chikungunya and dengue and where present may pose a threat to human health. Since 2003 A. albopictus is also present in Southern Switzerland in the Canton of Ticino and has since then been continuously surveyed and controlled, mainly by larviciding and larval source reduction. The Italian communities just across the border, however, lack such a surveillance and intervention programme. Here, we examined the seasonal and spatial abundance of A. albopictus in forest and urban areas across the Swiss-Italian border during the mosquito’s active season in 2012 and 2013, and measured the susceptibility of the local mosquito population against larvicides in use. We found that mosquito densities peaked between end of August and early September and that they were higher in Italy and in the urban areas. Laboratory bioassays showed that the local mosquito population is still susceptible to the applied larvicide, Bacilus thuringiensis var. israelensis (Bti). Together the results support the hypothesis that the intervention programme in Ticino successfully lowers the local A. albopictus population.