Range Expansion of Lungworm (Umingmakstrongylus pallikuukensis) in Muskoxen on Victoria Island, Nunavut
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Muskox populations on the mainland of Canada between the Coppermine and Mackenzie Rivers, North West Territories, are infected with the lungworm Umingmakstrongylus pallikuukensis with a prevalence that approaches 100%. U. pallikuukensis is a member of the family Protostrongylidae and lives in nodules in the lungs, adjacent to the airways. The adult parasite needs a gastropod intermediate host for its development from first-stage larvae to third-stage larvae. The development of larvae of U. pallikuukensis is dependent on temperature and takes 4-6 weeks. The prepatent period is approximately 90 days, and the patent period can be at least 2 years. For this study, there were 30 lungs and 28 fecal samples from a community hunt in 2008 at Lady Franklin Point, Victoria Island, and 24 lungs and 182 fecal samples from a commercial harvest in 2009 near Cambridge Bay, Victoria Island, available. A modification of the Baermann technique was used to detect larvae in the fecal samples. The lungs were dissected and the recovered cysts were measured and dissected. From Lady Franklin Point 29 lungs and 19 fecal samples were positive; all 24 lungs and 182 fecal samples from Cambridge Bay were negative. The cysts contain adult worms, larvae, eggs and debris. Histology of some cysts showed little inflammation and a moderate chronicity, tough unlikely more than a few months. Evaluation of old records and communication about muskox harvests in the past show no evidence that U. pallikuukensis was present at Victoria Island in the past. The findings of this study suggest that there is range expansion of U. pallikuukensis on Victoria Island, but not all muskox herds on this island are infected.