Serological and Molecular Detection of Zoonotic Pathogens in European Bison (Bison bonasus) and Associated Ticks from Poland.

As wild ungulates, including European bison, increasingly share habitats with livestock, surveillance of infectious zoonotic agents in their populations is essential for both wildlife and public health. This study aimed to screen for selected zoonotic pathogens in European bison from Poland. Samples (blood, ticks, and spleen) were collected from 86 animals. Serum was used for serological testing using commercial ELISA kits for Borrelia burgdorferi sensu lato, Brucella spp., and hepatitis E virus (HEV); ticks were analysed by real-time PCR targeting B. burgdorferi s.l., Anaplasma phagocytophilum, and Brucella spp., and spleen samples from Brucella-seropositive animals were cultured. Serological analysis revealed that 53.9% of European bison were seropositive for B. burgdorferi s.l., while 25.3% showed seroreactivity against Brucella spp.; however, these findings were not supported by molecular or culture confirmation, suggesting possible non-specific reactions or past exposure. No serum samples were positive for HEV antibodies, and no Brucella spp. were isolated from spleen samples. Molecular analysis of ticks detected B. burgdorferi s.l. DNA in 4.8% of samples and sequencing confirmed Borrelia garinii in one case. In contrast, A. phagocytophilum DNA was detected in 59.0% of ticks. No ticks tested positive for Brucella DNA. These findings indicate substantial exposure of European bison to tick-borne pathogens, particularly B. burgdorferi s.l. and A. phagocytophilum. However, Brucella seropositivity should be interpreted with caution due to the lack of molecular or culture confirmation.