Other Intestinal Protozoa and Trichomonas Vaginalis

Excerpt

This chapter discusses human protozoan parasites belonging to seven different genera—- Giardia, Trichomonas, Dientamoeba, Chilomastix, Balantidium, Isospora, and Cryptosporidium. Giardia, Trichomonas, Chilomastix and Dientamoeba are classified as flagellates; Balantidium coli is a ciliate, and Isospora and Cryptosporidium are coccidians. All are intestinal parasites that are transmitted by the fecal-oral route, except for T vaginalis, which is usually spread by sexual contact. The most common of these intestinal parasites is Giardia lamblia. Of the three trichomonads discussed, only the common genitourinary tract inhabitant T vaginalis causes disease. Dientamoeba (D. fragilis) is infrequently reported as a cause of clinical infections. Chilomastix (C. mesnili), an intestinal flagellate that parasitizes humans, is generally considered nonpathogenic, and representatives of the genera Balantidium and Isospora, although not commonly encountered in humans, are considered capable of causing disease. Observations indicate that protozoa in the genus Cryptosporidium may cause mild or severe gastroenteritis.