. Animal parasites and human disease. Insect Vectors; Parasites; Parasitic Diseases; Medical parasitology; Insects as carriers of disease. 126 INTESTINAL FLAGELLATES AND CILIATES Ciliates Balantidium coli, — Although several species of ciliates have been recorded as human parasites, there is only one species, Balantidium coli (Fig. 34A), normally parasitic in hogs, which is common enough to be of any importance. This large ciliate stands next to Endamceba histolytica among the Protozoa as a. Fig. 34. Balantidium coli; A, free ciliate from intestine; n., nucleus; c. v., contractile vacuoles; f.
. Animal parasites and human disease. Insect Vectors; Parasites; Parasitic Diseases; Medical parasitology; Insects as carriers of disease. 126 INTESTINAL FLAGELLATES AND CILIATES Ciliates Balantidium coli, — Although several species of ciliates have been recorded as human parasites, there is only one species, Balantidium coli (Fig. 34A), normally parasitic in hogs, which is common enough to be of any importance. This large ciliate stands next to Endamceba histolytica among the Protozoa as a. Fig. 34. Balantidium coli; A, free ciliate from intestine; n., nucleus; c. v., contractile vacuoles; f. v., food vacuole; cyt., cytostome. B, cyst, as passed in faeces, containing two parasites. X about 500. (After Wenyon.) cause of human dysentery. It is a large animal for a protozoan, averaging from 50 to 100 n (7^q to ^£o of an inch) in length, and thus being visible to the naked eye. Its body is oval and en- tirely covered with cilia, and at the anterior end there is a gash- like slit leading to the mouth or " cytostome " (Fig. 34, cyt.). The large bean-shaped nucleus (Fig. 34, n.) lies near the middle of the body and near each end is a pulsating cavity or contractile vacuole (Fig. 34, ) which excretes waste matter. These parasites multiply by transverse division, often so rapidly that the animals do not have time to grow to full size and so become very small. When ready to leave the body they form an oval cyst about themselves. Sometimes two occupy a single cyst (Fig. 34B), and later fuse together. Since the ciliated bodies of the protozoans can be seen, under a microscope, inside the large transparent cysts, their identification is not difficult. The cysts can exist outside the body for a long time, awaiting an opportunity for Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectparasites, bookyear19
