Molecular detection of Setaria tundra (Nematoda: Filarioidea) and an unidentified filarial species in mosquitoes in Germany

Abstract

BackgroundKnowledge of the potential vector role of Culicidae mosquitoes in Germany is very scanty, and until recently it was generally assumed that they are not involved in the transmission of anthroponotic or zoonotic pathogens in this country. However, anticipated changes in the course of global warming and globalization may alter their status.MethodsWe conducted a molecular mass screening of mosquitoes for filarial parasites using mitochondrial 12S rRNA-based real-time PCR.ResultsNo parasites causing disease in humans such as Dirofilaria spp. were detected in about 83,000 mosquitoes tested, which had been collected in 2009 and 2010 in 16 locations throughout Germany. However, minimum infection rates of up to 24 per 1000 mosquitoes were revealed, which could be attributed to mosquito infection with Setaria tundra and a yet unidentified second parasite. Setaria tundra was found to be widespread in southern Germany in various mosquito species, except Culex spp. In contrast, the unidentified filarial species was exclusively found in Culex spp. in northern Baden-Württemberg, and is likely to be a bird parasite.ConclusionsAlthough dirofilariasis appears to be emerging and spreading in Europe, the absence of Dirofilaria spp. or other zoonotic filariae in our sample allows the conclusion that the risk of autochthonous infection in Germany is still very low. Potential vectors of S. tundra in Germany are Ochlerotatus sticticus, Oc. cantans, Aedes vexans and Anopheles claviger. Technically, the synergism between entomologists, virologists and parasitologists, combined with state-of-the-art methods allows a very efficient near-real-time monitoring of a wide spectrum of both human and veterinary pathogens, including new distribution records of parasite species and the incrimination of their potential vectors.

First molecular identification of Dirofilaria spp. (Onchocercidae) in mosquitoes from Serbia

“…Nucleic acid was extracted from fresh mosquito pool homogenates with DiaExtract DNA Mini Kit (Diagon Ltd., Hungary) following the protocol provided by the manufacturer. A generic filarial real-time PCR targeting a 94 bp long fragment of the 12S ribosomal RNA (rRNA) gene from the mitochondrial genome was performed using the primers FILA-F, FILA-R, and probe FILA-P as previously described (Czajka et al 2012). TaqMan PCR assay was performed with GoTaq® G2 Flexi DNA Polymerase PCR kit (Promega) according to the manufacturer's protocol on LineGene 9600 platform (Bioer).…”

Putative filariosis outbreak in white and black rhinoceros at Meru National Park in Kenya

“…Hence, more studies are needed to understand the filarioid-navigating web including potential molecular analyses [28,29], and the range of underlying causal factors of its unexplicable emergence and re-emergence [24,30], which poses a substantial threat to the conservation of the global biodiversity [23]. …”

Filarial worm circulation by mosquitoes along an urbanization gradient in southern Spain

“…Although, the recorded prevalence was low, with only 0.16% (Bravo‐Barriga et al, ) and 0.27% (Morchón et al, ) of the mosquitoes tested providing positive results. As other vector‐borne pathogens, Dirofilaria distribution may have a heterogeneous spatial pattern, being detected in several studies, but not being detected in some cases in other European areas despite being tested in a large number of mosquitoes (Czajka et al, ). Additionally, other mosquito species present in the area that were underrepresented in this study (i.e.…”