Affected birds suffer losses in weight and survivors remain stunted. Dehydration and emaciation are the principal gross lesions. Muscles are dark and dry. The intestine usually appears to have lost muscle-tone. Intestinal contents are usually thin and watery, or may contain mucus.
Diagnosis depends upon history, symptoms and microscopic examination of intestinal contents.
A definite diagnosis cannot be made unless typical flagellated organisms can be detected in intestinal contents of the duodenum. Most flagellate organisms in the cecae are not disease producers.