Balantidium coli trophozoite (stained). Note the large kidney-bean-shaped macronucleus, fine layer of cilia surrounding the organism, and mouth-like structure. Trophozoites are typically seen in direct fecal smears.
Balantidium coli cyst (stained). Note the large kidney-bean shaped macronucleus.
Balantidium coli cyst (not stained). Note the large kidney-bean shaped macronucleus is not easily observed.
Cyst of Buxtonella sulcata. A ciliate found in the colon of cattle, B. sulcata exists in cyst form outside of the host. The ciliate form resembles Balantidium coli in swine. Pathogenesis is minimal and identification of cysts in feces is usually incidental.
Ichthyophthirius multifiliis trophont cross section in fish gill. Ich has two basic phases to its life cycle, the free-living stage which includes the infective tomites and cystic tomocysts, and the parasitic phase, consisting of feeding and reproducing trophonts, and is the stage found on skin scrapings of affected fish.
Trophont of Ichthyophthirius multifiliis from the skin of a fish. Trophonts can range greatly in size, but have a charcteristic horse shoe shaped macronucleus, cilliated buccal cavity near the anterior end, and an oval to round body.