[Enteric helminths of the mallard Anas platyrhynchos L., 1758 in the north-western part of Poland].

Although the mallard, Anas platyrhynchos, is the most common wild duck in Poland, as well as in the entire Palearctic, it is extremely rarely studied by comprehensive parasitological surveys. The aim of this study was to present a synthesis on the species composition of enteric helminths of the mallard in north-western Poland. The study was carried out in 1999-2006 and involved parasitic worms isolated from the alimentary tracts of 187 mallards (Anseriformes: Anatidae). Following isolation, the parasites were preserved in 70% ethylene and stained (flatworms) or viewed in transient light (nematodes and acanthocephalans). Taxonomic identity of the worms was determined using taxonomic keys and numerous original papers. The studies have revealed that the parasitic community of this host in the north-west part of Poland is relatively complex, composed of 51 species of helminths of four systematic groups: 16 digenean species, 23 tapeworms, 9 nematodes, and 3 acanthocephalans. The material also revealed five new to Polish fauna parasitic species: one trematode (Echinostoma miyagawai) and four tapeworms (Microsomacanthus baeri, M. pachycephala, Monotestilepis tadornae, and Sobolevicanthus aculeostileticus). On the other hand, for another 11 species (Prosthogonimus ovatus, Psilotrema simillimum, Australapatemon minor, Leucochloridiomorpha lutea, Psilostomum brevicolle, Echinocotyle rosseteri, Fimbriarioides sp., Retinometra giranensis, Anisakinae gen. sp., Pseudocapillaria mergi i Polymorphus magnus) the mallard was found to be a new host.