A protozoon organism can cause coccidiosis, which is a disease that affects the digestive tract of animals. Protozoa are single-celled organisms that can live in different environments, including soil and water, and can infect animals and humans. In the case of coccidiosis, the protozoan parasite infects the intestines of the host animal, causing diarrhea, weight loss, and other symptoms. Protozoa do not cause anthrax, rinderpest, or aspergillosis, which are caused by bacteria, viruses, and fungi, respectively.