Detection and molecular characterization of the mosquito-borne filarial nematode Setaria tundra in Danish roe deer ( Capreolus capreolus )

Abstract

Setaria tundra is a mosquito-borne filarial nematode of cervids in Europe. It has recently been associated with an emerging epidemic disease causing severe morbidity and mortality in reindeer and moose in Finland. Here, we present the first report of S. tundra in six roe deer (Capreolus capreolus) collected between October 2010 and March 2014 in Denmark. The deer originated from various localities across the country: the eastern part of the Jutland peninsular and four locations on the island Zealand. With the exception of one deer, with parasites residing in a transparent cyst just under the liver capsule, worms (ranging from 2 to >20/deer) were found free in the peritoneal cavity. The worms were identified as S. tundra by morphological examination and/or molecular typing of the mitochondrial 12S rRNA and cox1 genes, which showed 99.1–99.8% identity to previously published S. tundra isolates from Europe. Roe deer are generally considered as asymptomatic carriers and their numbers in Denmark have increased significantly in recent decades. In light of climatic changes which result in warmer, more humid weather in Scandinavia greater numbers of mosquitoes and, especially, improved conditions for development of parasite larvae in the mosquito vectors are expected, which may lead to increasing prevalence of S. tundra. Monitoring of this vector-borne parasite may thus be needed in order to enhance the knowledge of factors promoting its expansion and prevalence as well as predicting disease outbreaks.

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

“…vexans on C. capreolus revealed in the study performed in Germany (Börstler et al 2016) and identical S. tundra COI gene fragment sequences (Table 1) found in C. capreolus and Ae. vexans from Poland (in this study and in the study by Masny et al 2016), Germany (Kronefeld et al 2014), Denmark (Enemark et al 2017), Hungary (Zittra et al 2015), France (Ferri et al 2009), Italy (Favia et al 2003), and Spain (Angelone-Alasaad et al 2016) are an indication that Ae. vexans acquires S. tundra by feeding on C. capreolus .…”

“…infections. The parasite S. tundra was documented in many European countries: in reindeer in the former USSR (Rajewsky 1928), in reindeer from Sweden (Rehbinder 1990) and Norway (Kummeneje 1980), in roe deer from Bulgaria (Yanchev 1973) and Germany (Büttner 1978; Rehbein et al 2000; Czajka et al 2012), and roe deer from Italy (Favia et al 2003), Poland (Bednarski et al 2010; Kowal et al 2013; Kuligowska et al 2015), and Denmark (Enemark et al 2017). The veterinary importance of S .…”

Molecular Detection and Phylogenetic Analysis of Endosymbiont Wolbachia pipientis (Rickettsiales: Anaplasmataceae) Isolated from Dirofilaria immitis in Northwest of Iran

“…Wolbachia has also previously been isolated from W. bancrofti , Brugia malayi , O. volvulus , and Setaria tundra (29, 40–42). Recently, the study of the isolated O. volvulus from 4 African countries indicated that extensive intra species heterogeneity exists in the Wolbachia content of male and female adults of O. volvulus .…”

The first description of Setaria tundra (Issaitshikoff & Rajewskaya, 1928) in roe deer from Croatia

“…as vectors (vector-borne disease). Czajka et al (2012) screened mosquitoes in Germany for filarial parasites using RT PCR, and found minimum prevalence rates of up to 24 infected per 1000 mosquitoes, which were attributed mainly to Setaria tundra infection. In the final hosts adult females that inhabit the peritoneal cavity produce large numbers of microfilariae each day (in thousands) which end up in the blood (Nelson, 1966), and are taken up by the vectors.…”