Ascariasis is an infection caused by the parasite Ascaris lumbricoides, commonly called a roundworm. It can cause symptoms such as abdominal pain, constipation or diarrhea, and vomiting.
Although it most often lives in the intestines, Ascaris lumbricoides can also migrate to other parts of the body. Examples include the heart, lungs, gallbladder, and liver, particularly when the infection goes undiagnosed or treatment is incomplete.
Ascariasis is curable and is usually treated with antiparasitic medications prescribed by a primary care provider or pediatrician. Good hygiene habits are also important to help prevent reinfection and reduce roundworm transmission.
Common symptoms
The main symptoms of ascariasis are:
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Abdominal pain or discomfort;
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Nausea and vomiting;
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Diarrhea or constipation;
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Blood in the stool, in some cases;
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Excessive tiredness;
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Loss of appetite;
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Worms in the stool.
Because the parasite can spread beyond the intestines, other symptoms may appear depending on the affected area, such as coughing and shortness of breath when it develops in the lungs. In some cases, vomiting can occur containing worms when ascariasis affects the liver or gallbladder.
Ascariasis symptoms are related to how many parasites are in the body. The worms typically need to develop and be present in large numbers before symptoms start.
Confirming a diagnosis
In many cases, ascariasis can be diagnosed by a primary care provider, pediatrician, or infectious disease specialist based on symptoms alone.
Even so, a stool test is important to identify roundworm eggs, confirm the diagnosis, and guide treatment.
If symptoms suggest the infection may be outside the intestines, the clinician may order an X-ray. This can help check whether the parasite is developing in other parts of the body and assess how severe the infection is.
Transmission and spread
Ascariasis is transmitted by swallowing roundworm eggs, including through:
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Eating contaminated food or drinking contaminated water;
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Putting dirty hands in the mouth, especially in children playing in contaminated soil;
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Living in areas with limited access to safe drinking water;
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Living in places with inadequate sanitation, including open defecation;
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Using feces as fertilizer.
After the eggs are swallowed, larvae are released in the intestines and then travel through the bloodstream to the lungs.
From there, they move up to the trachea and may be swallowed again, returning to the intestines and developing into adult worms. In some situations, they can also be expelled through vomiting.
Treatment options
Ascariasis treatment should be guided by a primary care provider, pediatrician, or infectious disease specialist. It typically involves antiparasitic medications such as albendazole or mebendazole for 1 to 3 days.
Treatment with deworming medications is usually repeated after 1 to 3 months. This is because the medications kill adult worms, but parasite eggs may still remain in the body, and repeating treatment helps ensure complete elimination of roundworms.
If there are enough roundworms to cause an intestinal blockage, or if the parasite is present in other parts of the body, surgery may be needed. Surgery can remove the parasite and correct any damage it may have caused.
Prevention measures
The main ways to prevent ascariasis include:
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Washing hands and under the fingernails with soap and water after using the bathroom or changing diapers;
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Washing hands before preparing food;
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Avoiding putting dirty hands in the mouth, especially in children after playing in soil;
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Washing foods before preparing them;
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Cooking vegetables thoroughly;
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Avoiding direct contact with feces and not defecating outdoors;
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Drinking only safe drinking water.
In endemic regions, periodic treatment of the population may be recommended to reduce the release of parasite eggs in stool. It is also important to properly treat human feces when it may be used as fertilizer.