The parasitic fauna of the Chiloe wigeon Mareca sibilatrix (Anseriformes: Anatidae) from Ñuble region, Chile.

The Chiloe wigeon, Mareca sibilatrix (Anseriformes: Anatidae), is a native duck distributed mainly in Chile and Argentina. Although it is a common species in the Neotropical realm, studies on its parasitic fauna remain limited. This study aimed to gather additional data on host-parasite associations in M. sibilatrix. Thus, 18 birds from Ñuble region, central Chile, were subjected to parasitic examination. Ectoparasites and endoparasites obtained were stored in 70 % and 80 % ethanol, respectively. A total of 787 parasite individuals were isolated; all birds were parasitized by at least one parasite. In 14 (77.7 %) birds, a total of 179 ectoparasites belonging to six taxa were identified. Meanwhile, all dissected birds (100 %) harbored a total of 608 endoparasites belonging to 15 taxa. Ectoparasites corresponded to four taxa of chewing lice (four genera) and two feather mites (two genera). Meanwhile, endoparasites were represented by four tapeworms (four genera), five trematodes (four genera), five nematodes (five genera), and one nasal mite. Of recorded parasite species, two taxa represent new records to the Neotropical realm, 11 taxa (three ectoparasites and eight endoparasites) are new records for the parasitic fauna of Chile, and 15 taxa (three ectoparasites and twelve endoparasites) are recorded for the first time in M. sibilatrix. Additionally, the fluke Echinostoma echinatum is of zoonotic concern. This research contributes with valuable data to the understanding of parasitic diversity in waterfowl and emphasizes the role of M. sibilatrix as a host in various parasitic interactions within its distribution range.