Gastrointestinal helminths of woodland and barren ground caribou (Rangifer tarandus) in Canada, with keys to species

Abstract

A total of 21 species of parasitic helminths was recovered from wild and captive caribou. Gastrointestinal nematodes were represented by eight species of Ostertagiinae, four species of Nematodirinae, Trichostrongylus axei, T. vitrinus, Oesophagostomum venulosum, Trichuris ovis, Skrjabinema sp., and Capillaria sp. Other helminths included Dictyocaulus viviparus, Setaria yehi, and Moniezia sp. Nematodirus odocoilei, a common parasite of Odocoileus spp. is reported from caribou for the first time. Ostertagia leptospicularis is reported from North America for the first time. Illustrations and diagnostic keys are provided for the eggs, infective larvae, and adults of the gastrointestinal nematodes recovered from caribou.

Eimeria rangiferis (Protozoa: Eimeriidae) reported from caribou in Ameralik, West Greenland

“…Steele et al, (2013b) reported the presence of the strongyle Ostertagia gruehneri in AkiaManiitsoq caribou, however, it has not been reported in the adjacent Kangerlussuaq-Sisimiut caribou population (Clausen et al, 1980, Korsholm & Olesen, 1993Steele et al, 2013b). Morphology of our study's strongyle-type eggs (Figure 2) from Ameralik caribou coincides with descriptions of Ostertagia eggs (Thienpont et al, 1979;Fruetel & Lankester, 1989). Several strongyle nematodes, however, exhibit similar egg morphology making conclusive identification to genus or species impossible.…”

“…Length measurements and morphological examination were used to distinguish nematode egg type. Large (> 200µm) eggs are of the subfamily Nematodirinae (Fruetel & Lankester, 1989), while medium-sized (< 100µm) are a strongyle nematode (Rommel et al, 2000;Thienpont et al, 1979). Nematodirinae eggs were further identified using the key of Fruetel & Lankester (1989).…”

“…Large (> 200µm) eggs are of the subfamily Nematodirinae (Fruetel & Lankester, 1989), while medium-sized (< 100µm) are a strongyle nematode (Rommel et al, 2000;Thienpont et al, 1979). Nematodirinae eggs were further identified using the key of Fruetel & Lankester (1989). Identification of eimerids detected in our study followed Gudmundsdottir & Skírnisson (2005;2006).…”

“…It remains open if this is the same species. In key to ova of the gastrointestinal helminths of caribou in North America Fruetel & Lankester (1989) report that Nematodirinae eggs with mean length > 240 µm belong to genus Nematodirella and mean egg length differs among regions; eggs < 230 µm in length belong to genus Nematodirus. In North America genus Nematodirus is represented by three well-known species in caribou; N. odocoilei (maximum egg length 180 µm), N. tarandi and N. helvetianus, (maximum egg length of both species 228 µm).…”

Synopsis

“…Although trichostrongylid eggs cannot be positively identified to species or even genus, in reindeer faeces they are mostly Ostertagia gruehneri (Bye, 1987;Fruetel & Lankester, 1989). The reindeer trichostrongylids appear to be well-adapted to the arctic climate by hypobiosis; the development is sustained so that egg production is ceased in midwinter, which obviously saves both the parasites and the host.…”