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Estimates suggest that one quarter of the world's population is infected with the intestinal roundworm Ascaris lumbricoides. The vast majority of infected people are asymptomatic. Patients who are newly infected may have pulmonary symptoms (e.g. cough, wheezing) and eosinophilia due to larval migration through the lungs. Later, abdominal symptoms may develop because of the mechanical effects of the relatively large adult worm. Patients in this later stage do not demonstrate eosinophilia.
The adult A lumbricoides is a large, cream-colored worm. Adult males are 6-12 inches (15-30cm) in length, and adult females are 8-14 inches (20-35cm) in length. Adult worms can live in the small intestine for 6 months or longer.
Incidence; Causes & Development; Risk Factors
In the US, occurrence is uncommon. Approximately 4 million people in the United States are infected, mostly in the rural southeast. In developing countries, more than 1 in 4 people are infected (e.g. Southeast Asia [73% infected], Africa [12%], Central/South America [8%]).
The roundworm life cycle begins when eggs from adult female worms living in the intestine are passed out with feces. These eggs then contaminate the soil and, and in warm moist conditions, will develop to the stage where they can become infective. These eggs are then swallowed, for example on fruits or vegetables that have been watered with water containing contaminated soil. Once they are in the intestine (specifically, the duodenum), the eggs hatch into larvae which penetrate the wall of the intestine and enter blood or lymph vessels and end up in the lungs. There they continue to grow and develop, before moving to the throat, to be swallowed back down to the intestine. Here the worms grow and develop to maturity and start producing eggs.
Children, because of their habits (e.g. directly or indirectly consuming soil), are more commonly and more heavily infected than adults. Males are more likely to be infected because boys, it is believed, eat more dirt than girls do.
Signs & Symptoms
Most patients are asymptomatic. To become infected, a patient needs to consume soil contaminated 2-3 weeks before with infected feces. Infected patients are not directly contagious. Symptoms can be broken down into 2 categories: early (larval migration) and late (mechanical effects).
Early (4-16 days after egg ingestion) symptoms of the tissue-migratory phase include fever, cough, wheezing. Late (6-8 weeks after ingestion) GI symptoms resulting from mechanical irritation include vague abdominal complaints (i.e. cramping, nausea, vomiting); small bowel obstruction (mostly in children); pancreatitis (secondary to worm migration); cholecystitis (secondary to worm migration); appendicitis (less common, secondary to worm migration).
Physical signs include passage of adult worm(s) from mouth or anus; wheezing (early infection); mild abdominal tenderness (established infection).
Diagnosis & Tests
Adult females lay about 200,000 eggs per day, making diagnosis by stool examination easy.
Treatment & Prevention
Conventional treatment generally involves the use of drugs (Mebendazole/Vermox, Albendazole/Albenza, Piperazine citrate), and prevention is based mainly on good personal hygiene and food handling techniques.
Complications
Infection with A lumbricoides is very rarely fatal, but death may occur because of mechanical intestinal obstruction. Worm passage (from above or below) may cause significant consternation in patients and/or parents.
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Conditions that suggest Roundworm Infection:
Risk factors for Roundworm Infection:
Roundworm Infection suggests the following may be present:
Recommendations and treatments for Roundworm Infection: | | | | | Mineral |  MSM (Methyl Sulfonyl Methane) | Clinical testing suggests MSM has activity against a variety of parasites, including roundworms. It seems to discourage these infections by competing for binding receptor sites at the mucus membrane surface in the intestinal tract. |
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KEY | | Strong or generally accepted link |  | | Proven definite or direct link | | | May do some good |
GLOSSARY
Abdomen (Abdominal)
That part of the body between the chest and the hips that contains the stomach, intestines, liver, bladder, pancreas and other organs.
Ascaris lumbricoides (Ascariasis, Intestinal Roundworm)
The adult A lumbricoides is a large, cream-colored worm. Adult males are 6-12 inches (15-30cm) in length, and adult females are 8-14 inches (20-35cm) in length. Signs include passage of adult worm(s) from mouth or anus; wheezing (early infection); mild abdominal tenderness (established infection). Uncommon in the US (approximately 1.5% of people are infected, mainly in the rural southeast), it affects more than 25% of the population of Third World nations.
Asymptomatic
Not showing symptoms.
Centimeter (Centimeters, cm)
A metric unit of length equaling one hundredth of a meter, or ten millimeters. There are 2.54 millimeters in one inch.
Cholecystitis (Cholecystalgia)
Inflammation of the gall bladder and ducts, for example from the presence of passing stones, or following fasting or anorexia, or because of a spreading intestinal tract infection. Cholecystalgia: Cramps or tenesmus of the gall bladder or bile ducts.
Cramp (Cramping, Cramps)
A sudden, involuntary, painful muscular contraction.
Duodenum (Duodenal)
First portion of the small intestine between the pylorus and jejunum, connecting to the stomach.
Eosinophil (Eosinophilia, Eosinophils)
The eosinophils, ordinarily about 2% of the granulocyte count (60 to 75% of the white blood cells), increase in number in the presence of allergic disorders and parasitic infestations.
Gastrointestinal (GI, GI Tract)
Pertaining to the stomach, small and large intestines, colon, rectum, liver, pancreas, and gallbladder.
Lung (Lungs, Pulmonary)
Organ of the body, located in the chest cavity which is designed to bring oxygen from the air into the blood stream, while also expelling carbon dioxide and other waste gases out of the body. Pulmonary: Related to the lungs.
Lymph
A clear fluid that flows through lymph vessels and is collected from the tissues throughout the body. Its function is to nourish tissue cells and return waste matter to the bloodstream. The lymph system eventually connects with and adds to venous circulation.
Mucus (Mucous)
The viscous, slippery substance that consists chiefly of mucin, water, cells, and inorganic salts and is secreted as a protective lubricant coating by cells and glands of the mucous membranes.
Nausea
Symptoms resulting from an inclination to vomit.
Pancreatitis
Inflammation of the pancreas. Symptoms begin as those of acute pancreatitis: a gradual or sudden severe pain in the center part of the upper abdomen goes through to the back, perhaps becoming worse when eating and building to a persistent pain; nausea and vomiting; fever; jaundice (yellowing of the skin); shock; weight loss; symptoms of diabetes mellitus. Chronic pancreatitis occurs when the symptoms of acute pancreatitis continue to recur.
Parasite (Parasites, Parasitic, Parasitical)
An organism living in or on another organism.
Small Intestine (Small Bowel)
The small intestine lies between the stomach and the large intestine. It is about 6 meters (20 feet) long and its primary function is to digest (break down) food and absorb nutrients (vitamins, minerals, proteins, carbohydrates, and fats). The small intestine makes up more than 70% of the length and 90% of the surface area of the gastrointestinal (GI) tract.
Last updated: Oct 08, 2008
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