It is the biological study of protozoa.

Protozoa is a group of eukaryotic microorganisms classified in the animal kingdom. Parasitic protozoa are one of the protozoa. Parasites occur in all major groups. Relatively few parasites are distinctly pathogenic, causing amebiasis, visceral leishmaniasis, sleeping sickness, Chagas’ disease, malaria, tick fever of cattle, dourine of horses, and other diseases.