Prevalence of coronaviruses in European bison (Bison bonasus) in Poland.

Coronaviruses have been confirmed to infect a variety of species, but only one case of associated winter dysentery of European bison has been described. The study aimed to analyze the prevalence, and define the impact on the species conservation, the source of coronavirus infection, and the role of the European bison in the transmission of the pathogen in Poland. Molecular and serological screening was performed on 409 European bison from 6 free-ranging and 14 captive herds over the period of 6 years (2017-2023). Presence of coronavirus was confirmed in one nasal swab by pancoronavirus RT-PCR and in 3 nasal swab samples by bovine coronavirus (BCoV) specific real time RT-PCR. The detected virus showed high (> 98%) homology in both RdRp and Spike genes to BCoV strains characterised recently in Polish cattle and strains isolated from wild cervids in Italy. Antibodies specific to BCoV were found in 6.4% of tested samples, all originating from free-ranging animals. Seroprevalence was higher in adult animals over 5 years of age (p = 0.0015) and in females (p = 0.09). Our results suggest that European bison play only a limited role as reservoirs of bovine-like coronaviruses. Although the most probable source of infections in the European bison population in Poland is cattle, other wild ruminants could also be involved. In addition, the zoonotic potential of bovine coronaviruses is quite low.

Parasitological Monitoring of European Bison (Bison Bonasus) from Three Forests of North-eastern Poland between 2014 and 2016.

INTRODUCTION: 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. MATERIAL AND METHODS: Faecal samples were collected in the Bialowieza, Knyszynska, and Borecka Forests between 2014 and 2016, as were some from an area neighbouring the Bialowieza Forest outside the Natura 2000 protected area. Parasites were detected in individual samples with the flotation, decanting and Baermann methods. RESULTS: 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. CONCLUSION: 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.