The European bison (Bison bonasus) is an endangered species which faces a range of health threats. As little is known of exposure of European bison to paratuberculosis caused by Mycobacterium avium spp. paratuberculosis, known to cause losses in cattle, the aim of the present study was to conduct serological survey in Polish bison herds. Between September 2018 and February 2021, blood samples were collected from 165 European bison from different regions of Poland. Samples were taken whenever the animals were immobilized (e.g., putting on telemetry collars) as well as from any dead animal. The serum samples were tested with ELISA. Three individuals, originating from different captive herds, were found to be seropositive. In conclusion, it was found that Mycobacterium avium subsp. paratuberculosis infections are not currently a problem in European bison, especially in free-range herds.

The European bison (Bison bonasus) is an endangered species whose restitution requires systematic health monitoring. The most practical way to test clinical material from large wildlife is by serological methods. Recently, the most serious health hazard faced by the European bison population was tuberculosis. However, climate change and globalization have resulted in the arrival of more exotic diseases, one of which is epizootic hemorrhagic disease (EHD), caused by the epizootic hemorrhagic disease virus (EHDV). EHD is an arthropodtransmitted viral disease noted mainly in ungulates, especially ruminants. Clinical signs vary depending on the virus serotype and host. The aim of this study was to determine the prevalence of EHD in European bison by serological testing for antibodies to EHDV. Serum samples were collected from 90 European bison living in different regions of Poland and tested with PrioCHECK™ EHDV Ab Serum Kit (Thermofisher, US). One of the bison (from the Knyszyńska Forest) had a positive result. It cannot be excluded, however, that the result was a false positive. There is a need for further EHDV serology monitoring in European bison and other wildlife, particularly in the Knyszyńska Forest.