ABSTRACT

Ducks are incredibly diverse and distributed worldwide. Coccidiosis is one of the most common and economically important diseases of ducks. Duck coccidia belong to four genera, Eimeria, Isospora, Tyzzeria, and Wenyonella. Both domestic and wild ducks are commonly infected with coccidian. Clinical infections of duck coccidia have been reported in the United States, Denmark, England, Japan, India, Canada, Iceland, and China. Most of these reports confirmed duck coccidian infection by finding endogenous stages in histological sections. The small intestines of ducks infected with Tyzzeria perniciosa are often distended and filled with blood and caseous exudate. T. perniciosa induced mortality spikes to 30%, and recovered ducks are usually associated with slow weight gain, demonstrating T. perniciosa as a great restraint to the duck industry. Cross-transmission experiments were performed only on a few species of duck coccidia. Detection of duck coccidia oocysts in feces or ureteral contents confirms diagnosis.