Protozoa

Protozoa are ubiquitous unicellular organisms of which only a small number are known to cause human disease. However, they can lead to profound morbidity and mortality. They are often categorized based on their primary site of infection, such as blood, tissue protozoa, as well as the CNS-tropic free-living amoeba. Blood and tissue protozoans cause malaria, American and African trypanosomiasis, leishmaniasis, toxoplasmosis, and babesiosis. The intestinal protozoa are a common cause of diarrhea and are widely distributed across the world. The free-living amoeba lead to often-fatal amoebic meningoencephalitis.