EN
Within 1992-2000. a total of 181 Białowieża Forest bison were examined from two winter herds. Twelf parasitic arthropod species were observed, a high infestation being typical of Demodex bisonianus, Chorioptes bovis, Ixodes ricinlls, Dermacentor reticulatus, and Bisonicola sedecimdecembrii. The infestation in section 422 herd being higher for B. sedecimdecembrii, I. ricinus, D, reticulatus, Ch. Bovis, D. bisonianus was slightly more prevalent in the section 391 herd, the intensity being, however, lower than that in the other herd. Among the remaining arthropods found in the Białowieża Forest European bison, some Lipoptena cervi occurred in both herds. Demodex sp. and Sarcoptes scabiei were recorded only in the section 422 herd, Ixodes persulcatus was present only in the section 391 bison and those kept in the reservation, while D. bovis, Psoroptes ovis. and Melophagus ovinus were found in the reserve bison only. In the present study, the largest differences in the extent of infestation involved the hair-dwelling arthropods (B. sedecimdecembrii, I. ricinus).