Enteritis in turkeys associated with an unusual flagellated protozoan (Cochlosoma anatis)

Outbreaks of enteritis associated with an unusual flagellated protozoan occurred in six California turkey flocks during the summer of 1992. Certain morphological and ultrastructural details of the parasite, which resembles Cochlosoma anatis, are illustrated with scanning and transmission electron micrographs. The flagellate attached to the intestinal mucosa by means of a sucker-like apparatus, and circular impressions of the sucker were created on the surface epithelium. Histological lesions were characterized by blunting and fusion of villi; cellular infiltration of the lamina propria with lymphocytes, plasma cells, histiocytes, and heterophils; and increased numbers of mitotic figures in crypt epithelium.