Ectoparasites of red foxes (Vulpes vulpes) with a particular focus on ticks in subcutaneous tissues

In the present study, we identified the ectoparasite communities of red foxes in three regions of Poland that encompassed two endemic regions for the occurrence of Dermacentor reticulatus, as well as a region that is free of this tick species ('gap' area). Our study sites were selected to enable the role of foxes as hosts for juvenile (nest dwelling) and adult (exophilic) D. reticulatus ticks to be determined, and to assess their contribution to the spread of this important vector of Babesia canis. We compared also ectoparasite communities between adult foxes with those of fox cubs. Finally, we carried out a systematic search for subcutaneous ticks determining their prevalence and abundance. In 2016-2018, 366 adult foxes and 25 live-trapped cubs were examined for ectoparasites. Ectoparasites were identified based on morphological features, PCR amplification and sequencing. The total prevalence of ectoparasites was higher in cubs (68%) than in adults (62.8%). In adults, 15 parasite species were recorded, including four tick species, seven flea species, scabies, and one Anopluran species each in the genera Felicola and Lipoptena. In cubs, six ectoparasite species were found, including Ixodes kaiseri, a species not found in adults. Although Ixodes ricinus and D. reticulatus were the dominant tick species on adult foxes, no D. reticulatus ticks were found on cubs. Subcutaneous ticks were common (38%) and abundant in all areas. Molecular analysis of subcutaneous nodules allowed the identification of 17 I. ricinus and five D. reticulatus. In conclusion, red foxes play a minor role as hosts of D. reticulatus.