Ascariasis
Ascariasis is an infection with the parasitic roundworm Ascaris lumbricoides.
Causes
People get ascariasis by consuming food or drink that is contaminated with roundworm eggs. Ascariasis is the most common intestinal worm infection. It is related to poor sanitation. People who live in places where human feces (stool) are used as fertilizer are also at risk for this disease.
Once consumed, the eggs hatch and release immature roundworms called larvae inside the small intestine. Within a few days, the larvae move through the bloodstream to the lungs. They travel up through the large airways of the lungs and are swallowed back into the stomach and small intestine.
As the larvae move through the lungs they may cause an uncommon form of pneumonia called eosinophilic pneumonia. Eosinophils are a type of white blood cell. Once the larvae are back in the small intestine, they mature into adult roundworms. Adult worms live in the small intestine, where they lay eggs that are present in feces. They can live 10 to 24 months.
An estimated 1 billion people are infected worldwide. Ascariasis occurs in people of all ages, though children are affected more severely than adults.
Symptoms
Most of the time, there are no symptoms. If there are symptoms, they may include:
-
Bloody sputum (mucus coughed up by the lower airways)
Bloody sputum
Coughing up blood is the spitting up of blood or bloody mucus from the lungs and throat (respiratory tract). Hemoptysis is the medical term for cough...
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Wheezing
Wheezing is a high-pitched whistling sound during breathing. It occurs when air moves through narrowed breathing tubes in the lungs.
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- Passing worms in stool
-
Shortness of breath
Shortness of breath
Breathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough air
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-
Stomach pain
Stomach pain
Abdominal pain is pain that you feel anywhere between your chest and groin. This is often referred to as the stomach region or belly.
Read Article Now Book Mark Article - Vomiting or coughing up worms
- Worms leaving the body through the nose or mouth
Exams and Tests
The infected person may show signs of malnutrition. Tests to diagnose this condition include:
-
Abdominal x-ray or other imaging tests
Abdominal x-ray
An abdominal x-ray is an imaging test to look at organs and structures in the abdomen. Organs include the liver, spleen, stomach, and intestines. Wh...
Read Article Now Book Mark Article - Blood tests, including complete blood count and eosinophil count
Complete blood count
A complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...
Read Article Now Book Mark ArticleEosinophil count
An absolute eosinophil count is a blood test that measures the number of one type of white blood cells called eosinophils. Eosinophils become active...
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Stool exam to look for worms and worm eggs
Stool exam
Stool ova and parasites exam is a lab test to look for parasites or eggs (ova) in a stool sample. The parasites are associated with intestinal infec...
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Treatment
Treatment includes medicines such as albendazole that paralyze or kill intestinal parasitic worms.
If there is a blockage of the intestine caused by a large number of worms, a procedure called endoscopy may be used to remove the worms. In rare cases, surgery is needed.
Endoscopy
Endoscopy is a way of looking inside the body using a flexible tube that has a small camera and light on the end of it. This instrument is called an...
Read Article Now Book Mark ArticlePeople who are treated for roundworms should be checked again in 3 months. This involves examining the stools to check for eggs of the worm. If eggs are present, treatment should be given again.
Outlook (Prognosis)
Most people recover from symptoms of the infection, even without treatment. But they may continue to carry the worms in their body.
Complications can be caused by adult worms that move to certain organs, such as the:
- Appendix
- Bile duct
- Pancreas
If the worms multiply, they can block the intestine.
Possible Complications
These complications may occur:
- Appendicitis
- Blockage in the bile ducts of the liver
- Blockage in the intestine
- Hole in the gut
When to Contact a Medical Professional
Contact your health care provider if you have symptoms of ascariasis, particularly if you have traveled to an area where the disease is common. Also call if you have any of the following:
- Symptoms get worse
- Symptoms do not improve with treatment
- New symptoms occur
Prevention
Improved sanitation and hygiene in developing countries will reduce the risk in those areas. In places where ascariasis is common, people may be given deworming medicines as a preventive measure.
Reviewed By
Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Centers for Disease Control and Prevention website. Parasites-ascariasis. www.cdc.gov/sth/about/ascariasis.html. Updated June 13, 2024. Accessed June 18, 2024.
Mejia R, Weatherhead J, Hotez PJ. Intestinal nematodes (roundworms). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 286.
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