Occurrence and Spread of the Invasive Asian Bush Mosquito Aedes japonicus japonicus (Diptera: Culicidae) in West and North Germany since Detection in 2012 and 2013, Respectively.

Helge Kampen,Cornelius Kuhlisch,Doreen Walther,Dorothee E Scheuch,Andreas Fröhlich,Immo A Hansen

doi:10.1371/journal.pone.0167948

Helge Kampen, Cornelius Kuhlisch + Show 4 more

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https://doi.org/10.1371/journal.pone.0167948

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Abstract

The invasive Asian bush mosquito Aedes japonicus japonicus was first recognised as established in Germany in 2008. In addition to the first known and quickly expanding population in the southwestern part of the country, three separate populations were discovered in West, North and southeastern Germany in 2012, 2013 and 2015, respectively, by means of the ‘Mueckenatlas’, a German instrument of passive mosquito surveillance. Since the first findings of mosquito specimens in West and North Germany, these regions were checked annually for continuing colonisation and spread of the species. Both affected areas were covered by a virtual 10x10km2 grid pattern in the cells of which cemeteries were screened for immature stages of the mosquito. The cells were considered populated as soon as larvae or pupae were detected, whereas they were classified as negative when no mosquito stages were found in the cemeteries of at least three different towns or villages. Presence was also recorded when Ae. j. japonicus adults were submitted to the ‘Mueckenatlas’ from the respective cell or when there was evidence of local occurrence in localities other than cemeteries. Based on this approach, a significant expansion of the populated area was documented in West Germany since the first detection of Ae. j. japonicus in 2012 (increase in positive grid cells by more than 400%), while the North German population appears not to be expanding so far (reduction of positive grid cells by ca. 30% since 2013). As Ae. j. japonicus finds suitable climatic and ecological conditions in Germany, the differential expansion of the two populations might be attributed to the West German population being older and thus more firmly established than the closely related but younger North German population that might still be in its founder phase. However, geographic spread of all German populations in the future is anticipated. Continuous surveillance is recommended, as Ae. j. japonicus is a competent vector of several pathogens in the laboratory.

Highlights

As a result of globalisation and the worldwide trade with used tyres, lucky bamboo and waterholding machinery, Aedes mosquitoes are regularly transported around the world and introduced into non-endemic areas [1]
Cell M5, from which an Ae. j. japonicus specimen had been submitted to the ‘Mueckenatlas’ in 2012, remained negative until 2014 (Fig 2C), and only in 2015 were larvae demonstrated in this cell (Fig 2D), in a cemetery of a town different from where the ‘Mueckenatlas’ submission originated
The emergence and spread of the invasive Asian bush mosquito Ae. j. japonicus in North America and Europe are attributed to the broad ecological tolerance and adaptability of this mosquito species [36]

Summary

Introduction

As a result of globalisation and the worldwide trade with used tyres, lucky bamboo and waterholding machinery, Aedes mosquitoes are regularly transported around the world and introduced into non-endemic areas [1]. Japonicus is well adapted to climatic conditions in certain parts of North America and in Central Europe. It showed up in the United States in the 1990s where it is widely distributed in 33 states including Hawaii [4]. Molecular population analyses showed two microsatellite genetic signatures in Europe suggesting that at least two independent introduction events took place [10, 11]

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