The first detection of Ashworthius sidemi (Nematoda, Trichostrongylidae) in roe deer (Capreolus capreolus) in Russia.

Ashworthius sidemi is a blood-sucking nematode, which has spread out among wild ruminants in several European countries during last decades. The nematode has recently been detected in cattle as well. The distribution of A. sidemi in Russia has not been sufficiently clarified yet. In European part of Russia A. sidemi was formerly registered in sika deer (Cervus nippon) and maral (Cervus elaphus sibiricus) introduced from Asia, and also in aboriginal elks (Alces alces). Taking into consideration the presence of other species of ruminants susceptible to A. sidemi in European Russia, it is necessary to control the spread of this parasite. The specimens of males and females of A. sidemi were found during the autopsies of three naturally infected roe deer (Capreolus capreolus) from Voronezh and Tver regions (European Russia). The species affiliation of the discovered nematodes was determined according to morphological features and confirmed using molecular techniques. The intensity of infection with A. sidemi in two roe deer from Voronezh was 11 and 63 nematodes, and it was 17 nematodes in roe deer from Tver. All of the discovered specimens of A. sidemi were referred to juvenile forms based on features of male bursa morphology and weak development of female reproductive system. In Russia, A. sidemi has not previously been detected in C. capreolus and the present report constitutes the first record of the parasite occurrence in this species of ruminant.