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

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.

Impacts of urbanisation level and distance from potential natural mosquito breeding habitats on the abundance of canine dirofilariosis

“…The flight distance of potential mosquito vector(s) is likely to have an effect on the spatial patterns found. In 2013 a mosquito trapping was performed at the case site of the first dirofilariosis cases in Szeged to detect the potential vectors of D. immitis (Zittra et al, 2015). The authors observed the presence of D. immitis in Cx.…”

“…pipiens complex are regarded as the dominant vectors of dirofilariosis in several countries of Europe, e.g. in Spain (Morchón et al, 2007), Italy (Cancrini et al, 2006), Turkey (Yildirim et al, 2011) and Hungary (Zittra et al, 2015). Morchón et al (2012) published a detailed review about the potential mosquito vectors of animal dirofilariosis in Europe.…”

Trapping blood-feeding mosquitoes (Diptera: Culicidae) in the first lethal canine dirofi lariasis site in Szeged, Hungary

“…Almost 95% of the material was dominated by C. pipiens which is a confi rmed vector of D. immitis in Hungary (Kartman 1953, Zittra et al 2015. Walters & Lavoipierre (1982), Rossi et al (1999), Zittra et al (2015) (Vezzani et al 2011) or by detecting the fi larial DNA in the mosquito (Yildrim et al 2011).…”

“…Walters & Lavoipierre (1982), Rossi et al (1999), Zittra et al (2015) (Vezzani et al 2011) or by detecting the fi larial DNA in the mosquito (Yildrim et al 2011). Aranda et al (1998) emphasised the importance of C. pipiens in the transmission of the fi laria in canine cases.…”

“…Culex quinquefasciatus (Say, 1823) in Brasil and Culex tritaeniorhynchus (Giles, 1901) in Japan) are the most important vectors of Dirofi laria immitis (Cancrini et al 2003, Labarthe et al 1998, Tesh 1989. Zittra et al (2015) performed mosquito trapping in 2013 to detect the potential vectors of Dirofi laria immitis in Szeged, and detected the presence of Dirofi laria immitis pathogens in Culex pipiens Linnaeus, 1758 and Ochlerotatus caspius (Pallas, 1771). We aimed the collection of the blood-feeding fauna of the case site regardless of the previous authors.…”