Gastrointestinal Helminths of a European Moose Population in Poland.

Parasitic infections have a negative impact on the fecundity and survival of wild ruminants, particularly moose; however, despite being more susceptible to parasitic diseases than other wild cervids, they remain poorly examined in this regard. Therefore, the aim of the present study was to identify gastrointestinal and liver helminth species of the moose population in central Europe, assess the factors contributing to infection intensities and examine their impact on moose health. Abomasum, small intestine, caecum and liver samples were collected from 46 moose in Poland and evaluated for helminth parasite fauna and histopathological changes. Additionally, 289 moose fecal samples were analyzed for the presence of eggs, oocysts and larvae of parasites. In total, 19 parasite taxa were identified. The most prevalent were Mazamastrongylus dagestanica and Ostertagia antipini, which are typical nematodes of moose, together with Spiculopteragia boehmi and O. leptospicularis, characteristic also of other cervids. Parasite species diversity and abomasal parasitic infection intensity were higher in adult moose than in yearlings and calves. The numbers of histopathological lesions depended on the intensity of parasitic infections, and were most severe in the livers of moose infected with Parafasciolopsis fasciolaemorpha. The analysis of fecal samples revealed several regional differences in the levels of parasite eggs, oocysts and larvae shedding. Our findings indicate an accumulation of parasite infections over time in moose, which may be related to high environmental parasite pressure, possibly connected with high moose density and the presence of wetlands; they also serve as the most comprehensive study of moose parasites in central Europe to date.