The Genus Leucocytozoon, commonly referred to as Leucocytozoon, is a blood parasite that infects birds. This genus contains several species, including Leucocytozoon caulleryi, Leucocytozoon smithi, and Leucocytozoon sabrazesi. These parasitic organisms can cause disease and death in birds, particularly in young or weakened individuals. Synonyms for Leucocytozoon include avian malaria, haemoproteus, and protozoan parasites. These terms are often used interchangeably with Leucocytozoon, as they all refer to blood parasites that affect avian species. Understanding the various synonyms for this genus is important for researchers and veterinarians who study and treat avian diseases.