Ascaris is an intestinal parasite of humans. It is the most common human worm infection. The larvae and adult worms live in the small intestine and can cause intestinal disease.

Ascaris lives in the intestine, and Ascaris eggs are passed in the feces of infected persons. Eggs are deposited in the soil when an infected person defecates outside, or their feces are deposited in the soil. This can happen if the feces of an infected person are used as fertilizer. The eggs can mature into a form that is infective. Ascariasis is caused by ingesting infective eggs. Infection can happen when putting contaminated hands or fingers in the mouth. Consuming vegetables or fruits that have not been carefully cooked, washed, or peeled can also cause infection.

Infection occurs worldwide in warm and humid climates where sanitation and hygiene are poor. This includes temperate zones during warmer months. Persons in these areas are at risk if soil contaminated with human feces enters their mouths. Eating vegetables or fruit that have not been carefully washed, peeled or cooked. Ascariasis is now uncommon in the United States.

People infected with Ascaris often show no symptoms. If symptoms do occur, they can be light and include abdominal discomfort. Heavy infections can cause intestinal blockage and impair growth in children. Other symptoms such as cough are due to the migration of the worms through the body.

Healthcare providers can diagnose ascariasis by taking a stool sample and using a microscope to look for the presence of eggs. Some people notice infection when a worm is passed in their stool or is coughed up. If this happens, bring in the worm specimen to your healthcare provider for a diagnosis.

• Avoid contact with soil that may be contaminated with human feces. This includes soil with human fecal matter ("night soil") used to fertilize crops.

• Wash your hands with soap and warm water before handling food.

• Teach children the importance of washing hands to prevent infection.

• Wash, peel, or cook all raw vegetables and fruits before eating, especially those that have been grown in soil that has been fertilized with manure. 

• not defecating outdoors, and by
• effective sewage disposal systems.

Anthelminthic medications are drugs that rid the body of parasitic worms. They include albendazole and mebendazole and are the drugs of choice for treatment. Infections are generally treated for 1-3 days. The recommended medications are effective.

In developing countries, groups at higher risk for soil-transmitted helminth infections are often treated without a prior stool examination. These infections include hookworm, Ascaris, and whipworm. Treating in this way is called preventive treatment (or "preventive chemotherapy"). The high-risk groups identified by the World Health Organization include preschool and school-age children. Women of childbearing age (including pregnant women in the 2nd and 3rd trimesters and lactating women) are also at risk. Adults in occupations where there is a high risk of heavy infections are also a high-risk group. School-age children are often treated through school health programs. Preschool children and pregnant women are often treated at visits to health clinics.

The soil-transmitted helminths and other "neglected tropical diseases" are sometimes treated through mass drug administrations. Soil-transmitted helminths include hookworm, Ascaris, and whipworm. "Neglected tropical diseases" include river blindness, lymphatic filariasis, schistosomiasis, and trachoma. Since the drugs used are safe and inexpensive or donated, entire risk groups are offered preventive treatment. Mass drug administrations are conducted periodically (often annually). Drug distributors commonly go door-to-door to administer treatment. Multiple neglected tropical diseases are often treated simultaneously using MDAs.