Eimeria is a genus of protozoan parasites that infect animals, particularly poultry and cattle. These parasites cause coccidiosis, a disease that can lead to weight loss, decreased egg production, and even death in infected animals. There are several synonyms for Eimeria including coccidian parasites, coccidiosis organisms, and Eimeriid parasites. Some other related terms include sporozoites, which are the infective stage of the parasite, and oocysts, which are the spore-like structures that the parasites produce in order to spread to other hosts. Effective management of coccidiosis in animal husbandry requires careful attention to hygiene, nutrition, and targeted use of anticoccidials.