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Key Features

  • Abdominal cramps and discomfort

  • Large, white or reddish, round worms, or ova in the feces

  • Ascaris lumbricoides infection is caused by contact with eggs or larvae that thrive in the moist soil of the tropics and subtropics

  • Children infected with these worms are at increased risk for malnutrition, stunted growth, intellectual disability, and cognitive and education deficits

  • Larvae hatch, penetrate the intestinal wall, enter the venous system, reach the alveoli, are coughed up the trachea and swallowed, returning to the small intestine, where they mature

  • Female lays thousands of eggs daily

Clinical Findings

  • Most infections are asymptomatic

  • Moderate to heavy infections are associated with abdominal pain, weight loss, anorexia, diarrhea, and vomiting, and may lead to malnutrition

  • Acute transient eosinophilic pneumonitis (Löffler syndrome) may occur during the larval migratory phase

  • Appendicitis, common bile duct obstruction (resulting in biliary colic, cholangitis, or pancreatitis), or peritonitis can be caused by worm migration


  • Large roundworms (1.5–4 cm) are observed in the stool or by microscopic detection of the ova on stool examination


  • Highly effective regimens include

    • Albendazole (400 mg in a single dose, or 200 mg in children 1–2 years of age)

    • Mebendazole (100 mg twice a day for 3 days or 500 mg once)

    • Pyrantel pamoate (a single dose of 11 mg/kg; maximum 1 g)

  • Piperazine (150 mg/kg initially, followed by six doses of 65 mg/kg every 12 hours by nasogastric tube)

    • Used in cases of intestinal or biliary obstruction

    • Can be used to paralyze the worms and help relieve obstruction

  • Surgical removal is occasionally required

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