Common parasites of the European bison include gastro-intestinal and pulmonary nematodes, liver flukes (Fasciola hepatica), tapeworms, and protozoa of the genus Coccidia. This study compared the extensiveness and intensities of European bison parasitic invasions in three north-eastern Polish forests in different seasons and queried the role of parasitological monitoring in sanitary and hygienic control of feeding places. Faecal samples were collected in the Białowieża, Knyszyńska, and Borecka Forests between 2014 and 2016, as were some from an area neighbouring the Białowieża Forest outside the Natura 2000 protected area. Parasites were detected in individual samples with the flotation, decanting and Baermann methods. The eggs of Trichostrongylidae, Aonchotheca sp., Nematodirus sp., Strongyloides spp., Trichuris sp., Moniezia spp., and Fasciola hepatica; the larvae of Dictyocaulus viviparus; and the oocytes of Eimeria spp. were identified. Significant variation in invasion intensity and diversity was seen by origin and season. The relationships were assessed first by univariable tests and next multivariately, when origin and season emerged as the major risk factors for exposure to most of the parasites. The differences in the level of parasitic infection between the forests did not have implications for its sufficiency to cause clinical symptoms. However, the associations and risk factors found enable the necessary preventive measures to be taken to protect the E. bison from exposure or decrease the risks. Additionally, parasitological monitoring is appropriate as the method of sanitary and hygienic control of European bison winter feeding places. Threats to public health through adventitious invasions by zoonotic factors such as F. hepatica have been identified.

Introduction: The aim of the study was to determine the prevalence of intestinal helminths in red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in the Augustów Primeval Forest (north-eastern Poland), with particular regard to zoonotic parasites.Material and Methods: Intestines from 53 raccoon dogs and 66 red foxes were examined with the use of sedimentation and counting technique (SCT). Samples of faeces from 51 red foxes and 50 raccoon dogs were examined with the use of flotation method.Results: Parasitic helminths were found by SCT in 98.5% of red foxes and 96.2% of raccoon dogs. Both species were infected with: Alaria alata (93.9% and 94.3%, respectively), hookworms (68.2% and 83.0%), Apophallus spp. (7.6% and 15.1%), Mesocestoides spp. (57.6% and 24.5%), Taenia spp. (40.9% and 1.9%), and Toxocara/Toxascaris nematodes (33.3% 15.1%). Echinococcus multilocularis was detected only in red foxes (6.1%), but trematodes Echinostomatidae and nematodes Molineus spp. only in raccoon dogs (18.9% and 41.5%, respectively). Additionally, Capillaria spp. eggs were detected by flotation method in 78.4% of foxes and 20.0% of raccoon dogs.Conclusion: The study showed a very high percentage of red foxes and raccoon dogs infected with intestinal helminths in the Augustów Primeval Forest. Moreover, dangerous zoonotic parasites also were found, which should be taken into consideration in the assessment of infection risk for humans in this region.