Protozoal infections

Abstract

Protozoa (Greek = the first animal, obsolete name) are eukaryotic unicellular organisms that are considered to be of animal origin. They have a cell membrane and, unlike bacteria, a cell nucleus. They are widespread pathogens and can cause serious disease manifestations. They have gained importance as the cause of opportunistic diseases (e.g., in patients with HIV/AIDS). Infections with protozoa are often difficult to treat; prophylaxis by immunization does not yet exist. Owing to their size, protozoa are often found in tissue and various body secretions (stool, other body fluids). Of the important human diseases caused by protozoa, only leishmaniasis, trichomoniasis, and (occasionally) amebiasis and rhinosporidiosis, manifest on the skin and mucous membranes.