Introduction
Roundworms, also known as Ascaris lumbricoides, infect humans. Infection by the worm is called ascariasis. It's more prevalent in the tropics and subtropics--especially in those areas with questionable water supplies and generally poor hygienic practices. According to the Centers for Disease Control and Prevention, it's rare in the U.S. and more likely to be contracted on a trip abroad.
The infection starts with the ingestion of infective eggs in food or water contaminated by feces. The infective egg hatches into a larval form in the intestines and migrates in the bloodstream to the lungs, where it undergoes further development. The nearly adult worm then crawls up into the pharynx and is swallowed into the digestive tract. Full development into the adult worm takes place in the intestine. The adult female worm lives in the intestine and lays eggs, which are passed out in the feces.
Symptoms are usually related to worm load. Most common symptoms are lethargy, diffuse, non-specific abdominal pains, nausea and vomiting. There may be some weight loss and abdominal bloating, especially in children.
Treatment
Ascaris is diagnosed by finding adult worms or eggs of the worm in stool samples. Sometimes, in high worm loads, live worms can be vomited or coughed up.
The drug of choice for treatment of ascariasis is Mebendazole, which kills the worms. It requires treatment over the course of three days. Pyrantel palmoate is another option for treatment. Both of these drugs are effective in eliminating the adult worms from the intestines.
A follow-up stool sample is usually required after two weeks of treatment. This is to ensure that all worms were cleared. Treatment may be repeated if Ascaris eggs are found in the stool at the two-weeks visit. This is possible if there were worms in other stages of development and in other sites of the body other than the intestine at the time of treatment
In highly prevalent areas, children receive empirical treatment every six months to keep the worm loads down and reduce health effects of the infection.
Prevention
Prevention of roundworm infection is achieved by improving water supply and general sanitation. Health education aimed at promoting proper hand washing and food hygeine is an invaluable tool in reducing prevalence of the infection.
Prompt and proper treatment of infected cases also reduce the reservoir of the disease. Occasional "deworming" campaigns in highly prevalent areas also reduce the worm burden and impact of the disease.
