Ascariasis is an intestinal worm infestation present worldwide, though mostly in tropical climates.

Ascaris lumbricoides is a nematode (round worm) parasite that can reach up to 40 cm in length. As with most parasites, Ascaris have a complex life cycle that begins with ingesting their eggs. After hatching in the gut, immature forms of the parasite travel to the heart and lungs, causing a type of pneumonia. They then migrate into the throat where they are swallowed, enter the gut again, and develop into adult worms. The eggs they lay (240,000 per worm per day) pass out with feces, to begin their cycle again when contaminated food or water is ingested.

Digestive Tract and Lungs

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  • Ingesting food or water contaminated by feces containing eggs

Risk Factors

The following factors increase your chances of developing ascariasis:

  • Preschool age or younger
  • Travel to developing countries
  • Living in southern states of the US
  • Eating unsanitary food
  • Drinking unclean water


If you experience any of these symptoms do not assume it is due to ascariasis. These symptoms may be caused by other health conditions. If you experience any one of them, and have been exposed to risks, see your physician.

  • Pneumonia (dry cough and fever)
  • Wheezing
  • Abdominal cramps
  • Vomiting
  • Malnutrition, especially in children
  • Passing a worm either by mouth, nose, or rectum
  • Diseases caused by Ascaris


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Your doctor will ask about your symptoms, travel and medical history, and perform a physical exam. You may be referred to a gastroenterologist or a specialist in tropical diseases. Tests may include the following:

  • Blood and urine tests
  • Stool specimens to search for worm eggs
  • Intestinal x-rays or ultrasound imaging


It is common to have more than one intestinal parasite. You may need to be treated for several. Talk with your doctor about the best treatment plan for you. Treatment options include the following:

  • Drugs—Mebendazole, albendazole, and pyrantel pamoate are all effective medications that kill Ascariasis.
  • Endoscopy or surgery—Intestinal obstruction from a large number of worms may require further intervention.


To help reduce your chances of getting ascariasis, take the following steps:

  • Avoid foods prepared without proper sanitary precautions, such as unwashed hands.
  • Avoid water and other drinks possibly from contaminated sources.
  • Peel, cook, or wash vegetables in an appropriate cleaning solution if possibly fertilized with human excrement.
  • Wash hands when leaving the bathroom.