Eimeria acervulina is a species of Eimeria that causes coccidiosis in older poultry. Lesions are limited to the anterior or first third of the small intestine. Diagnosis is made by on necropsy based on location and the pathognomic white to gray striations that appear on the mucosa or inner surface of the small intestine. Scrapings of the mucosa from diseased birds can reveal oocysts.