The parasites of the mallard duck (Anas platyrhynchos) as an indicator of health status and quality of the environment.

The mallard duck (Anas platyrhynchos) is a host to internal and external parasites. A heavy parasite burden indicates poor immunological status and a pathogen-contaminated environment. The present study describes the macroscopic and microscopic examination of isolated intestines and gizzards of 130 mallard ducks from birds kept in the breeding farm. Scrapings of intestinal mucosa were examined by flotation and with the sedimentation method. The results of the flotation method indicate the presence of coccidia oocysts in the ileum scrapings from one of five male mallards aged six weeks, one out of five aged 10 weeks and three out of five aged 12 weeks. In female mallards, oocysts were found in two of five birds aged 12 weeks and in two of five aged 16 weeks. No macroscopic lesions were found in the intestinal mucosa. Adult forms of the nematode Amidostomum anseris were found in the gizzards of six mallards aged 20 weeks and in two aged 22 weeks. The relatively low prevalence of parasitic infections reflects the purity of the environment, good immunity status of the birds and good management of the farm.