PRELIMINARY RESULTS OF THE HELMINTHOLOGICAL STUDY ON THE KRASNOBOR GROUP OF THE WILD REINDEER IN THE ARKHANGELSK REGION

Abstract

In November 2021, 21 samples of freshly excreted faeces were collected from reindeer (Rangifer tarandus Linnaeus, 1758) in the Krasnoborsky District of the Arkhangelsk Region. Each sample was examined for sexually mature adult helminths and their fragments, and then divided into parts. The first part was subjected to coprolarvoscopy using the Vajda method. The second part was subjected to flotation coproovoscopy using the Darling method. The third part was subjected to sedimentation method of coproovoscopy using sequential washing. Parasitic nematodes of the order Strongylida were found: eggs of gastrointestinal parasites (prevalence = 57%) and first-instar larvae of helminths of the Protostrongylidae family (prevalence = 62%), the so-called DSL (dorsal-spined larvae). Morphologically, they correspond to the description of a typical (and, as it was believed, the only one from the Protostrongylidae family) brain nematode of the reindeer, Elaphostrongylus rangiferi. However, these larvae were morphometrically heterogeneous: groups with sizes of about 337 and 374 µm are within the range of 309–375 given by the species descriptor, but groups of larvae with a length of about 391 and 415 µm exceed such range. This also indicates their taxonomic diversity. In addition, some of the found larvae had pathological extensions of the body, both in the esophagus area and along a greater length. Molecular phylogenetic studies have been planned.