Abstract
Historically known as the yellow fever mosquito, Aedes aegypti invaded Madeira Island in 2005 and was the vector of the island’s first dengue outbreak in 2012. We have studied genetic variation at 16 microsatellites and two mitochondrial DNA genes in temporal samples of Madeira Island, in order to assess the origin of the invasion and the population structure of this mosquito vector. Our results indicated at least two independent colonization events occurred on the island, both having a South American source population. In both scenarios, Venezuela was the most probable origin of these introductions, a result that is in accordance with the socioeconomic relations between this country and Madeira Island. Once introduced, Ae. aegypti has rapidly expanded along the southern coast of the island and reached a maximum effective population size (Ne) in 2012, coincident with the dengue epidemic. After the outbreak, there was a 10-fold reduction in Ne estimates, possibly reflecting the impact of community-based vector control measures implemented during the outbreak. These findings have implications for mosquito surveillance not only for Madeira Island, but also for other European regions where Aedes mosquitoes are expanding.
Highlights
Arbovirus transmission is becoming an increasing public health threat in Europe, mainly due to the establishment of invasive mosquito vectors and importation of arboviruses by viremic travelers[1]
No pair of loci was consistently associated across samples, which suggests an absence of linkage disequilibrium among loci
Results of a Discriminant Analysis of Principal Components (DAPC) analysis conducted with the Madeira/South America subset confirmed a closer relationship between Madeira Island and the samples of Caracas, Venezuela, and São Sebastião, Brazil (Fig. 5)
Summary
Arbovirus transmission is becoming an increasing public health threat in Europe, mainly due to the establishment of invasive mosquito vectors and importation of arboviruses by viremic travelers[1]. Epidemics of chikungunya and dengue have been reported over the last 20 years, notably in Italy (2007, 2017)[4,5], France (2010, 2017)[6,7] and Croatia (2010)[8] Another mosquito species responsible for arbovirus transmission is Aedes aegypti, previously present in Europe until mid-20th century and re-established in Madeira and in the Black Sea region[3]. In the Portuguese island of Madeira, Ae. aegypti was first reported in 2005, in the vicinity of Funchal city Since this mosquito has subsequently expanded its distribution throughout the southern coast of the island[9,10], being detected in Santa Cruz (East) in 2008 and in Paúl do Mar (West) in 2012 (Fig. 1). Previous studies showed that Ae. aegypti from Madeira is able to transmit dengue, chikungunya and Zika viruses[17,18], pinpointing the potential risk of local arbovirus transmission
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
