Screening of mosquitoes for filarioid helminths in urban areas in south western Poland\u2014common patterns in European Setaria tundra xenomonitoring studies

Katarzyna Rydzanicz,Wioletta Rozej-Bielicka,Aleksander Masny,Elzbieta Golab

doi:10.1007/s00436-018-6134-x

Katarzyna Rydzanicz, Wioletta Rozej-Bielicka + Show 2 more

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https://doi.org/10.1007/s00436-018-6134-x

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Abstract

In recent years, numerous studies screening mosquitoes for filarioid helminths (xenomonitoring) have been performed in Europe. The entomological monitoring of filarial nematode infections in mosquitoes by molecular xenomonitoring might serve as the measure of the rate at which humans and animals expose mosquitoes to microfilariae and the rate at which animals and humans are exposed to the bites of the infected mosquitoes. We hypothesized that combining the data obtained from molecular xenomonitoring and phenological studies of mosquitoes in the urban environment would provide insights into the transmission risk of filarial diseases. In our search for Dirofilaria spp.-infected mosquitoes, we have found Setaria tundra-infected ones instead, as in many other European studies. We have observed that cross-reactivity in PCR assays for Dirofilaria repens, Dirofilaria immitis, and S. tundra COI gene detection was the rule rather than the exception. S. tundra infections were mainly found in Aedes mosquitoes. The differences in the diurnal rhythm of Aedes and Culex mosquitoes did not seem a likely explanation for the lack of S. tundra infections in Culex mosquitoes. The similarity of S. tundra COI gene sequences found in Aedes vexans and Aedes caspius mosquitoes and in roe deer in many European studies, supported by data on Ae. vexans biology, suggested host preference as the most likely cause of the mosquito genus-biased infections. High diversity of the COI gene sequences isolated in the city of Wroclaw in south western Poland and the presence of identical or almost identical sequences in mosquitoes and roe deer across Europe suggests that S. tundra has been established in most of Europe for a very long time.

Highlights

Filarial nematodes are parasites of tissues and body cavities of all classes of vertebrates other than fishes (Anderson 2000) and pose a threat to humans, domestic animals, and wildlife (WHO 2007)
Both S. tundra and Dirofilaria repens were detected in the same xenomonitoring studies (Czajka et al 2012; Kronefeld et al 2014; Zittra et al 2015; Kemenesi et al 2015), and in most cases, the detection of S. tundra was a result of xenomonitoring mosquitoes for Dirofilaria spp
There was no information on the Dirofilaria spp. infection status of the dogs in the vicinity of our xenomonitoring study site; in the Lower Silesia region were our site was located, approximately 3% of dogs were infected with D. repens (Demiaszkiewicz et al 2014)

Summary

Introduction

Filarial nematodes are parasites of tissues and body cavities of all classes of vertebrates other than fishes (Anderson 2000) and pose a threat to humans, domestic animals, and wildlife (WHO 2007). Detection of Setaria tundra and Dirofilaria spp. by PCR xenomonitoring of mosquitoes may serve as an example of molecular xenomonitoring applicability for indirect filariae presence detection in local populations of the vertebrate hosts (Czajka et al 2012; Latrofa et al 2012; Bocková et al 2013; Czajka et al 2014; Kronefeld et al 2014; Silbermayr et al 2014; Rudolf et al 2014; Zittra et al 2015; Kemenesi et al 2015; Șuleșco et al 2016a, b; Kurucz et al 2016; Masny et al 2016). Other authors described Ae. vexans as a potential vector of D. repens (Bocková et al 2015; Rudolf et al 2014)

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