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Disease Information, Treatments and Possible Cures
Ascariasis (Roundworm)
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.
How common is ascariasis?
Ascariasis is the most common human worm infection. Infection occurs worldwide and is most common in tropical and subtropical areas where sanitation and hygiene are poor. Children are infected more often than adults. In the United States, infection is rare, but most common in rural areas of the southeast.
The following factors increase your chances of developing ascariasis:
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.
How is an Ascaris infection spread?
Ascaris eggs are found in human feces. After feces contaminates the soil, the eggs become infectious after a few weeks. Infection occurs when a person accidentally ingests (swallows) infectious Ascaris eggs. Once in the stomach, immature worms hatch from the eggs. The larvae are carried through the lungs and then to the throat where they are swallowed. Once swallowed, they reach the intestines and develop into adult worms. Adult female worms lay eggs that are then passed in feces; this cycle will take between 2-3 months.
Pigs can be infected with another species of Ascaris. Occasionally, a pig Ascaris infection can be spread to humans; this occurs when infective eggs, found in the soil and manure, are ingested. Infection is more likely if pig feces is used as fertilizer in the garden; crops then become contaminated with Ascaris eggs.
Diagnosis
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:
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:
To help reduce your chances of getting ascariasis, take the following steps:
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Avoid contacting soil that may be contaminated with human feces.
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Do not defecate outdoors.
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Dispose of diapers properly.
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Wash hands with soap and water before handling food.
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When traveling to countries where sanitation and hygiene are poor, avoid water or food that may be contaminated.
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Wash, peel or cook all raw vegetables and fruits before eating.
RESOURCES:
Center for Disease Control (CDC)
http://www.cdc.gov
The Nemours Foundation
http://kidshealth.org
World Health Organization
http://www.who.int
Communicable Disease Control (CDC) Unit
Manitoba Health, Public Health Branch
http://www.gov.mb.ca/health/publichealth/cdc/index.html
Ascariasis. DynaMed website. Available at: http://www.dynamicmedical.com/dynamed.nsf?opendatabase. Accessed October 4, 2005.
Beers MH, Berkow R. The Merck Manual, 17th ed. West Point, PA: Merck & Co;1999.
Weller PF, Nutman TB. Intestinal nematodes. In: Kasper DL et al., eds. Harrison's Principles of Internal Medicine, 16th ed. New York: McGraw-Hill; 2005:1256-1257.
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