Psorosperms, also known as sporozoa, belong to the lowest form of protozoa, and owing to their being found within the cells are known as cytozoa.
The ameba coli belongs to the protozoa, and is associated with tropical dysentery, and is found in the stools and the coats of the intestines; also in tropical abscesses of the liver.
The hematozoa of malaria has been considered in the etiology of malaria, where they were classified with the protozoa.
Coccidium Oviforme.—This species of psorosperms occasionally gives rise to hepatic diseases in man, though in animals, especially in the rabbit, it is quite common. It gives rise to the formation of nodules or tumors in the liver, which may be of sufficient size to be palpable. The liver is quite tender, physical examination causing pain. There may be chills, followed by severe fever, terminating in death. When they invade the kidneys and ureters there is hematuria and a constant desire to micturate.
The coccidium perforans and the coccidium bigeminum infect the intestinal canal, giving rise to nausea, vomiting, diarrhea, and symptoms of a typhoid character.
External or cutaneous coccidia give rise to papillomatous developments of the skin, and are located on the face and abdomen. Coccidia are also found in Paget's disease of the nipple, and in carcinoma and epithelioma, but whether they possess any etiological significance has not yet been determined.
Treatment.—Aside from prophylactic measures, treatment has been experimental and not attended by very brilliant results. A thorough cleansing of such vegetables as greens of various kinds, lettuce, cabbage, spinach, water-cresses, etc., that possibly may be contaminated from the excreta of rabbits and mice, is all-important in the prevention of the disease.