Screening blood-fed mosquitoes for the diagnosis of filarioid helminths and avian malaria.

Carina Zittra,Josef Harl,Alice Laciny,Barbara Eigner,Szilárd Pinnyei,Katrin Kieser,Katja Silbermayr,Zsanett Kocziha,Éva Fok,Hans-Peter Fuehrer,Georg G Duscher

doi:10.1186/s13071-015-0637-4

Abstract

BackgroundBoth Dirofilaria repens and recently D. immitis are known to be endemic in Hungary. As one of several recent cases, the fatal case of a dog infested with D. immitis in Szeged, Southern Hungary, received attention from the media. Hence it was decided to catch mosquitoes in the garden where the dog lived to screen for filarioid helminths and Plasmodium spp. using molecular tools.MethodsMosquitoes were caught in Szeged, in the garden where the infected dog was kept, in July 2013 with M-360 electric mosquito traps and were stored in ethanol until further procedure. Female mosquitoes were classified to genus level by morphology. Each mosquito was homogenized and analyzed for filarioid helminths and avian malaria using standardized PCR techniques. Positive mosquito samples were further identified to species level by comparing a section of the mitochondrial COI gene to GenBank® entries.ResultsIn this study, 267 blood-fed mosquitoes were caught in July 2013 in Szeged. Subsequent molecular screening revealed that not only D. immitis was present in the analyzed specimens but also DNA of D. repens, Setaria tundra and Plasmodium spp. was confirmed.ConclusionsThe analysis of blood-fed mosquitoes for the diagnosis of Dirofilaria spp. and other mosquito-borne pathogens seems to be an adequate technique to evaluate if filarioid helminths are present in a certain area. Usually only unfed female mosquitoes are analyzed for epidemiological studies. However, blood-fed mosquitoes can only be used for screening if a pathogen is present because the role of the mosquito as vector cannot be classified (blood of bitten host). Furthermore, Setaria tundra was confirmed for the first time in Hungary.

Highlights

Both Dirofilaria repens and recently D. immitis are known to be endemic in Hungary
In this study 267 blood-fed mosquitoes were caught with the M-360 electronic mosquito trap in Szeged, Southern Hungary in June 2013
The analysis of blood-fed mosquitoes for the diagnosis of Dirofilaria spp. and other mosquito-borne pathogens seems to be an adequate technique to evaluate if parasites such as filarioid helminths are present in a certain area

Summary

Introduction

Both Dirofilaria repens and recently D. immitis are known to be endemic in Hungary. As one of several recent cases, the fatal case of a dog infested with D. immitis in Szeged, Southern Hungary, received attention from the media. Culiseta, Aedes, Anopheles, and Coquillettidia have been mentioned as being incriminated in the transmission cycle of filarioidal infections [2] Both D. repens and D. immitis are emerging causative agents of parasitic zoonoses in Europe occurring in domestic and wild carnivores and are transmitted by mosquitoes [3]. Climatic changes are considered to be the main reason for the expansion of geographic ranges in parasites [3] and influence the development and longevity of their hosts; both the hosts and parasites are currently expanding to northern areas in Europe These findings were underlined by an increasing number of diagnosed filarioid infections in countries such as Austria, Germany, the United Kingdom, the Netherlands, Sweden, and Hungary [2]. Further global drivers like trade, travel (movement of dogs across Europe), and insecticide

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