EN
Parasitological autopsy of 31 european bisons, 9 red-deers and 3 roe-deers was made in Białowieża Forest in the period 1983-1988. Together 20 species of nematods were found, from them as much as 18 in bisons, 6 in red-deers and 8 in roe-deers. The highest intensity and 100% of extensity was shown by nematods from subfamily Ostertagiinae. Four species of this subfamily (O. leptospicularis, O. kolchida, S. boehmi i S. mathevossiani) have been permanently adapted by bisons from cervids, however two species of nematods typical for bisons and cattle (O. ostertagii and O. lyrata) have not been adopted by deers. Besides, bisons adopted from deers the following species of nematods: T. capricola, C. pectinata; N. roscidus, N. europaeus and from moose N. alcidis. Bisons gave to red-deers only C. bilobata, and roe-deers have not adopted any nematods from bisons. B. trigonocephalum and S. dagestanica found in roe-deers are in Poland typical parasites of mooses.