Di " erences in parasite diversity , prevalence , and intensity assessed through analyses of fecal samples from two West Greenland caribou populations

32 (1), 2012 This journal is published under the terms of the Creative Commons Attribution 3.0 Unported License Editor in Chief: Birgitta Åhman, Technical Editor Eva Wiklund and Graphic Design: Bertil Larsson, www.rangifer.no Introduction Many northern communities depend on caribou (Rangifer tarandus groenlandicus) as a dietary staple and for their contributions to northern economies and cultures. In Rangifer sp., experimental removal of gastrointestinal helminth parasites has been associated with increased fat reserves and pregnancy rates, and it is generally accepted that the e"ects of these parasites on individuals can in#uence population dynamics and herd sustainability (Albon et al., 2002; Stien et al., 2002).


Introduction
Many northern communities depend on caribou (Rangifer tarandus groenlandicus) as a dietary staple and for their contributions to northern economies and cultures.In Rangifer sp., experimental removal of gastrointestinal helminth parasites has been associated with increased fat reserves and pregnancy rates, and it is generally accepted that the e ects of these parasites on individuals can in uence population dynamics and herd sustainability (Albon et al., 2002;Stien et al., 2002).

Study Area
West Greenland is home to several populations of caribou, with Akia-Maniitsoq (AM = 24, 000) and Kangerlussuaq-Sisimiut (KS = 98, 300) the two largest (Cuyler et al., 2011).e ranges of these two populations extend eastwest from the Greenland ice cap to the coast and from 62°N to 68°N, with KS the more northerly.
ey are isolated from other caribou populations by extensive ord systems and from each other by the Sukkertoppen icecap, although movement between herds is theoretically possible (Cuyler et al., 2011).While AM and KS are genetically related (Jepsen et al., 2002), have adjacent ranges and lack predators (Melgaard, 1986), they are unique in their exposure to other ungulate species through human-mediated translocations and importations.e KS population shares its range with muskoxen (Ovibos moschatus wardi) translocated from east Greenland (Pedersen & Aastrup, 2000), whereas AM has seen transient introductions of cattle, horses, sheep, and goats , 2012 (Norlund, 1936;Rose et al., 1984), and the importation of semi-domestic Norwegian reindeer (R. t. tarandus) into a neighbouring range (Cuyler, 1999).e presence of introduced ungulates may have in uenced parasite diversity in these native caribou populations.
Gastrointestinal parasite diversity is poorly de ned for animals in west Greenland, with the two previous studies focusing solely on ungulates from the KS range.Raundrup (2005) sampled muskoxen from this area and reported the presence of 'trichostrongyle' eggs and larvae which she attributes to Ostertagia (Teladorsagia) circumcincta, however she provides no morphological or molecular data to support this.Korsholm and Olesen (1993) did a smaller, but more detailed study not only on muskoxen (n = 5), but also caribou (n = 5) from the KS range.In caribou, these authors reported the abomasal nematodes Teladorsagia circumcincta and Marshallagia marshalli, as well as Eimeria oocysts.Along with these parasites, muskoxen were also positive for Nematodirella longissimespiculata, Nematodirus helvetianus, and Moniezia expansa.To date, no similar work has been done for AM, although warbles (Hypoderma tarandi) and nose bots (Cephenemyia trompe) have been evaluated in both populations (Cuyler et al., 2012).e purpose of our work was to do a fecal survey of gastrointestinal parasites in the AM and KS caribou populations.We expected that, due to their common ancestry and neighboring ranges, there would be no di erences between parasite species present in the two populations.

Methods
Collections for this study took place during International Polar Year as part of an initiative by the CircumArctic Rangifer Monitoring and Assessment (CARMA) network (Kutz et al., in press).Adult female caribou (≥ 3 years), subadults (1-2 years) and their calves-at-heel (<1 year) were collected opportunistically through scienti c hunts from Mar. 29 -Apr.13, 2008 (AM) and Mar. 3 -17, 2009 (KS).Rectal fecal samples were collected, frozen, and transported to the University of Calgary where they were processed using a modi ed Wisconsin double centrifugation-sugar otation technique (Hoar et al., 2009).Eggs and oocysts were identi ed to family or genus based on morphology (Foreyt, 2001).Eggs identi ed as having typical 'strongyle-egg' morphology can belong to a number of di erent genera, however in arctic and subarctic environments the abomasal nematodes Ostertagia gruehneri and Teladorsagia boreoarcticus are the most common in Rangifer sp.(Hoberg et al., 2001;Kutz et al., 2012).Also producing 'strongyle-type' eggs, Teladorsagia circumcincta has been previously reported in KS by Korsholm & Olesen (1993). is identi cation should be revisited as it preceded the description of the morphologically similar T. boreoarcticus and it is now recognised that most descriptions of T. circumcincta in arctic hosts are mistaken (Hoberg et al., 1999;Kutz et al., 2012).

Results
We observed di erences between AM and KS in regards to the diversity of parasites present, prevalence (percent of samples positive), and intensity (eggs per gram feces from positive samples) (Table 1).'Strongyle-type', Nematodirinae and Anoplocephalidae eggs, and Eimeria oocysts were found in both populations.Marshallagia spp.eggs were common in KS samples, but absent entirely from AM.
Prevalence and intensity of 'strongyle-type' eggs were much higher in AM than KS, which may re ect di erences in species diversity, host genetics or health status, timing of sampling, or sampling years (Baker et al., 2001;Baker et al., 1998;Dunn, 1969;Irvine et al., 2001).Nematodirinae eggs, produced by the small intestinal nematodes Nematodirus spp. or Nematodirella spp., were found in both populations, but with very di erent patterns of distribution.In AM, these eggs were only present in samples from calves, as is expected for ruminants, however they were common in all age classes of KS. is suggests that there may be di erent species of nematodirines present in these two populations, which requires further investigation.
e presence of Marshallagia spp. in KS, but not AM, is likely the result of spill-over from introduced muskoxen (Pedersen & Aastrup, 2000), however the e ects of climatic conditions cannot be discounted.Marshallagia spp. in particular is more commonly found in arid regions (Meradi et al., 2011), and the drier climate of the KS region may be more suitable for this parasite than the AM range (Tamstorf, 2001).At least two varieties of Eimeria oocysts were present in each population, possibly E. hreindyria, E. mayeri, or E. rangiferis as these have all been reported previously in Rangifer sp.(Guðmundsdóttir, 2006).Di erences in prevalence and intensity of Eimeria spp. between the populations were non-signi cant, which may be a true result, or be due to our small sample size. is may also apply to our Anoplocephalidae results.

Conclusions
Our research has demonstrated that, although the AM and KS caribou populations are closely related genetically (Jepsen et al., 2002) and geographically, there are signi cant qualitative (species diversity) and quantitative (prevalence, intensity, and distribution across age classes) di erences in their parasites.Identi cation of parasites in this study was limited to morphological examination of eggs and, as such, we are only able to report to genus or family level.Species-level identi cations, currently underway, are expected to reveal greater di erences in diversity and provide deeper insight into the in uence of historical and contemporary factors on the parasite community of these caribou populations.
is work was supported by the Greenland Institute of Natural Resources, Environment Canada International Polar Year funding, NSERC Special Research Opportunities Grant, and Alberta Innovates.Stipend support is provided by the Faculty of Veterinary Medicine, University of Calgary.We thank the following individuals for their assistance with this project: Amanda Reith, Dean Brown, Jesse Invik,