A serological survey of pathogens associated with the respiratory and digestive system in the Polish European bison (Bison bonasus) population in 2017-2022.

BACKGROUND: The European bison (Bison bonasus) is a near threatened species and requires health monitoring. The aim of the present study was to determine the prevalence of antibodies to pathogens known to cause respiratory and digestive illness in ruminants. RESULTS: In the studied 328 European bison, the highest seroprevalence was observed for Bovine herpesvirus-1 (BoHV-1) (50.27%), Bovine Coronavirus (BCoV) (26.36%), and Bluetongue Virus (BTV) (12.83%). For Mycoplasma bovis strains and Bovine Viral Diarrhea Virus (BVDV), positive results were rare. Interestingly, a higher prevalence of BTV antibodies was noted in the northeastern populations and older animals. CONCLUSIONS: Our findings indicate that the Polish European bison population appears to have considerable contact with BoHV-1; however, this does not appear to be of great significance, as clinical symptoms and post-mortem lesions are rarely noted in Polish European bison population. The high seroprevalence of BTV in the north-east of Poland is an ongoing trend, also noted in previous studies. It is possible that European bison may perpetuate the virus in this region. This is the first report of antibodies for BCoV in European bison.

The Risk of False-Positive Serological Results for Paratuberculosis in Mycobacterium bovis-Infected Cattle.

Both bovine tuberculosis (BTB) and paratuberculosis (paraTB) continue to cause significant economic losses in cattle breeding; in addition, their etiological agents have zoonotic potential. Although the diagnostics of both diseases are still being improved, problems still remain, such as the potential for cross-reactivity to the antigens used in tests. The aim of the present study was to confirm whether animals known to harbor Mycobacterium bovis antibodies are at increased risk of yielding positive results in paraTB serotesting and, additionally, to verify the accuracy of three commonly used methods for confirming M. bovis infection: ELISA, the tuberculin skin test (TST), and the presence of gross lesions. Material was collected from 98 dairy cattle suspected of BTB due to TST-positive results. During postmortem examination, gross lesions were assessed visually. Blood, lymph nodes, and TB-suspected organs were collected. Serum was obtained from the collected blood and tested serologically for TB and paraTB. The tissues underwent standard microbiological testing for M. tuberculosis complex. Among the 98 TST-positive individuals, tuberculous gross lesions were detected in 57 (58.1%), MTBC were isolated in 83 (84.7%), and the ELISA test was positive for 21 (21.4%). None of the lesions characteristic for paraTB were detected. The chance of obtaining a positive TB result by ELISA was seven times higher using the ELISA-paraTB method; hence, there is a significant risk of obtaining false-positive serological results for paraTB in M. bovis-infected cattle. However, the hypothesis that infection of M. bovis or prior TST performance may have boosted the host immune response and therefore increased the sensitivity of the paraTB-ELISA cannot be excluded.