Eimeria fraterculae

Eimeria fraterculae is a species of alveolates belonging to the family Eimeriidae. It causes renal coccidiosis in the Atlantic puffin (Fratercula arctica).

Apart from its host-specificity, this coccidium can be recognised by the subspherical oocytes with unusually thick walls appearing distinctly greenish in colour. Coccidiosis caused by this parasite appears to be mild and nonfatal.