Coccidiosis is an infection caused by the coccidia parasites that predominantly affect the intestinal tract of animals. Pets can contract coccidiosis by ingesting coccidia oocysts (the parasite's eggs) present in the environment. These oocysts are typically found in contaminated soil, water, or feces. Pets may also become infected by eating infected tissue. The condition is more common in young or immunocompromised animals due to their less developed immune systems.