Detection of Usutu, Sindbis, and Batai Viruses in Mosquitoes (Diptera: Culicidae) Collected in Germany, 2011⁻2016.

Dorothee Scheuch,Ute Ziegler,Markus Keller,Eva Heym,Doreen Walther,Helge Kampen,Martin Groschup,Mandy Schäfer,Jonas Schmidt-Chanasit,Martin Eiden

doi:10.3390/v10070389

Abstract

Due to the emergence of non-endemic mosquito vectors and the recent outbreaks of mosquito-borne diseases, mosquito-borne pathogens are considered an increasing risk to public and animal health in Europe. To obtain a status quo regarding mosquito-borne viruses and their vectors in Germany, 97,648 mosquitoes collected from 2011 to 2016 throughout the country were screened for arboviruses. Mosquitoes were identified to species, pooled in groups of up to 50 individuals according to sampling location and date, and screened with different PCR assays for Flavi-, Alpha- and Orthobunyavirus RNA. Two pools tested positive for Usutu virus-RNA, two for Sindbis virus-RNA, and 24 for Batai virus-RNA. The pools consisted of Culex pipiens s.l., Culex modestus, Culex torrentium, Culiseta sp., Aedes vexans, Anopheles daciae, and Anopheles messeae mosquitoes and could be assigned to nine different collection sites, with seven of them located in northeastern Germany. Phylogenetic analyses of the viral RNA sequences showed relationships with strains of the viruses previously demonstrated in Germany. These findings confirm continuing mosquito-borne zoonotic arbovirus circulation even though only a rather small percentage of the screened samples tested positive. With respect to sampling sites and periods, virus circulation seems to be particularly intense in floodplains and after flooding events when mosquitoes develop in excessive numbers and where they have numerous avian hosts available to feed on.

Highlights

Due to globalization and climate warming, the number of cases and outbreaks of mosquito-borne diseases among humans and animals are likely to increase in Europe in the near future
West Nile virus (WNV), chikungunya virus (CHIKV), and dengue virus (DENV) have been associated with fatal disease [6,7,8]
Twenty-nine pools consisting of seven mosquito taxa tested positive for arbovirus-RNA, three for Sindbis virus (SINV), two for USUV- and 24 for Batai virus (BATV)-RNA (Table 1)

Summary

Introduction

Due to globalization and climate warming, the number of cases and outbreaks of mosquito-borne diseases among humans and animals are likely to increase in Europe in the near future. After the recent emergence of both efficient invasive mosquito vectors, such as Aedes aegypti and Aedes albopictus [1], and putatively exotic mosquito-borne disease agents, such as dengue and chikungunya viruses [2], mosquito research has experienced a renaissance in many European countries following decades of neglect. Nine mosquito-borne viruses have been shown to be endemic or temporarily circulate in Europe [2,4,5]: Usutu virus (USUV), Sindbis virus (SINV), Batai virus (BATV), Tahyna virus (TAHV), Inkoo virus (INKV), Lednice virus (LEDV), West Nile virus (WNV), chikungunya virus (CHIKV) and dengue virus (DENV). WNV, CHIKV, and DENV have been associated with fatal disease [6,7,8] Due to their occasional re-emergence, all nine viruses are apparently vectored by indigenous mosquito species, with the newly established invasive

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Conclusion