In trichuriasis, the adult worms are shaped like a whip. The long anterior threadlike portion of the worm consists of a cellular esophagus buried deep into the submucosa of the colon, making it difficult to dislodge. These adults are pinkish-gray and are 30 to 50 mm. long. The male is distinguished from the female by its coiled caudal extremity. The female produces 5000 to 10,000 eggs per day. The eggs are 50 to 55 microns long, golden brown with prominent characteristic bipolar plugs. Under favorable conditions they become infective in three to five weeks, and when ingested by man the first stage larva hatches in the small intestine and spends three to ten days in the intestinal villi. Then it passes down to the large bowel where it matures in 30 to 90 days. The adult worms live for years.
Of worldwide distribution, trichuriasis is most frequently encountered in the tropics. Often in a particular endemic locality, the infestation has a patchy distribution because of dense shade, heavy rainfall, and the clay soils that hold water as well as fecal pollution, thus facilitating transmission. In the United States, whipworm infection is found in the southern Appalachians and southwestern Louisiana; it is not infrequent in Puerto Rico.
The great majority of infections are asymptomatic; only heavy loads of worms cause clinical illness. The worms are distributed throughout the colon and rectum, and heavy infections may be associated with colic and diarrhea with blood. Trichuris trichiura abstracts 0.005 ml. of blood per worm from the host each day. In children in precarious iron balance a load of over 800 worms may be associated with an iron deficiency anemia. Up to 5000 worms have been recovered from heavily infected children. In such infections rectal prolapse may complicate the diarrhea, and the appearance of the congested mucosa associated with the whitish bodies of the worms has been described as the “coconut cake” rectum. Early infections may be associated with a mild blood eosinophilia. Trichuris has been implicated as a predisposing factor to acute amebic dysentery by
causing an initial breach of the mucosa, this sug gestion being based on finding a higher incidence of Trichuris in patients with acute bowel amebiasis than is normal for the area. Trichuris is often associated with other helminthic anc protozoal infections. Appendicitis and peritonitis w’th the presence of worms in the peritoneal cavity have been described.
Diagnosis is made by finding the eggs in the feces, either on direct smear or by concentration methods. In the rare Trichuiis dysentery the eggs may appear in aggiegates in the mucoid stools, together with eosinophils and Charcot-Leyden crystals. Egg counts below 10,000 per gram are unlikely to be associated with symptoms.
Treatment is not very satisfactory. Dithiazanine iodide was formerly used, but it has caused nine deaths, and has been withdrawn from the market. Treatment should be confined to heavily infected individuals presenting with symptoms and to those employed as food handlers, nurses, and so forth. Thiabendazole in a similar dose to that used in Strongyloides (25 mg. pei kilogram of body weight twice daily for two days) eradicates the infection in one third of cases, and the course can be repeated after one week. Stilbazium iodine (Monopar) appears to have a slightly higher cure rate, but is still under trial. Dichlorvos, a cholin-esterase inhibitor, has been shown to be very effective in adults, but further trials are needed.
