In populations where worm infections are widespread, it is common to find that most people are infected by a small number of worms, while a small number of people are heavily infected. This is characteristic of many types of worm infections. Those people who are infected with only a small number of worms usually have no symptoms. Migrating larvae As larval stages travel through the body, they may cause visceral damage, peritonitis and inflammation, enlargement of the liver or spleen, and an inflammation of the lungs. Pulmonary manifestations take place during larval migration and may present as Loeffler's syndrome, a transient respiratory illness associated with blood eosinophilia and pulmonary infiltrates with radiographic shadowing. Intestinal blockage Piece of intestine, blocked by worms, surgically removed from a 3-year-old boy in South Africa. The worms can occasionally cause intestinal blockage when large numbers get tangled into a bolus or they may migrate from the small intestine, which may require surgery. More than 796 A. lumbricoides worms weighing up to 550 g 19 ounces were recovered at autopsy from a 2-year-old South African girl. The worms had caused torsion and gangrene of the ileum, which was interpreted as the cause of death. The worms lack teeth. However they can rarely cause bowel perforations by inducing volvulus and closed-loop obstruction. Bowel obstruction Bowel obstruction may occur in up to 0.2 per 1000 per year. A worm may block the ampulla of Vater, or go into the main pancreatic duct, resulting in acute pancreatitis with raised serum levels of amylase and lipase. Occasionally, a worm can travel through the biliary tree and even into the gallbladder, causing acute cholangitis or acute cholecystitis. Allergies<unk>  may result in allergies to shrimp and dustmites due to the shared antigen, tropomyosin; this has not been confirmed in the laboratory. Malnutrition The worms in the intestine may cause malabsorption and anorexia which contribute to malnutrition. The malabsorption may be due to a loss of brush border enzymes, erosion and flattening of the villi, and inflammation of the lamina propria. Others Ascaris have an aversion to some general anesthetics and may exit the body, sometimes through the mouth, when an infected individual is put under general anesthesia.
Ascariasis
Toxocariasis
Acariasis
Schistosomiasis
Strongyloidiasis
Myiasis
Monorchism
Intestinal capillariasis