lumbricosis

infection by the nematode Ascaris lumbricoides, seen in temperate and tropical regions of the world; it is common in the southern mountain region of the United States and is associated with poor sanitation such as when human feces is used as fertilizer. The Ascaris eggs develop into larvae in the soil and on growing plants on which feces have been deposited. When such vegetables are eaten without having been properly washed or cooked, live larvae are carried into the digestive system along with the food. Migrating from the intestines into the blood, then to the lungs and the esophagus, the larvae finally return to the intestines, where they grow to maturity, reaching a length ranging from 15 to 35 cm (6 to 14 in).

Ascaris infection may go unsuspected until a worm is passed in the stool. But there may be colic or other abdominal symptoms, and occasionally the worms are vomited during their passage through the esophagus. In children, “wandering worms” may emerge through the skin near the navel, and in adults, near the groin. Infected children usually are thin because the worms consume vital nutrients and inhibit the digestion of proteins. Loss of appetite and angioneurotic edema are common, and the face may be swollen.

Accurate diagnosis of the presence and extent of Ascaris infection usually depends on the detection of eggs in a stool sample examined microscopically. Treatment involves the use of medications such as mebendazole or pyrantel. to destroy and expel the parasites, and is completely successful in nearly every case. Prevention of Ascaris infection depends primarily on the sanitary disposal of human feces and discontinuing their use as fertilizer. Also important are the thorough washing of hands before food is prepared, and the careful cleaning and cooking of possibly infected foods.