Giant Liver Fluke (Fascioloides magna) in Free-Ranging Muskoxen (Ovibos moschatus) of Nunavik, Québec, Canada.

We describe hepatic infections by giant liver fluke (Fascioloides magna) in free-ranging muskoxen (Ovibos moschatus) in Nunavik, Québec, Canada. Whole livers and feces were collected from 51 muskoxen (37 males, 14 females) harvested from 2007 to 2011. Prevalence of F. magna was very high (48/51, 94%; 95% confidence interval, 84-99), with the intensity of infection reaching up to 40 adult trematodes per liver (median, 4 flukes). The estimated percentage of macroscopically altered liver, which was evaluated in serial 1-cm-thick slices, ranged from 0.1% to 57.3% and was positively correlated with the number of parasites detected. Animals harvested near Tasiujaq had higher mean fluke intensity (7.2) than those near Kuujjuaq (2.6) in Nunavik, Québec, Canada. Despite the extent of the hepatic alterations in some individuals, no association was found between intensity of infection or liver alteration and the examined nutritional condition indices (depth of back fat, femur marrow fat percentage, and kidney fat index). Field observations suggest that infections by F. magna did not have a significant clinical impact on sampled muskoxen. The mean fluke intensity and the percentage of altered liver did not vary between sex and age. Fecal shedding of F. magna eggs was documented in some individuals, indicating that muskoxen could be characterized as a definitive host. Further research is needed to define the reservoir species and characterize the life cycle of this parasite in the Canadian Arctic.