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Ascariasis / Ascaris lumbricoides: Causes, Symptoms, Diagnosis, Prevention, Treatment and General home care of Ascariasis/ Ascaris lumbricoides

Ascaris is cosmopolitan in distribution. It is the most common helminthic infestation. It is estimated that about one-fourth of the world's population is infected . Prevalence rates of the order of 50 to 75 per cent have been registered in many Asian and Latin American countries .

Ascariasis is an intestinal infection caused by the parasitic roundworm Ascaris lumbricoides . Ascariasis is the most common human infection caused by worms in the world. Ascaris lumbricoides lives in the lumen of small intenstine, where it moves freely. Sexes are separate. The female measures 20-35 cm in length, and the male 12-30cm. Egg production is very heavy - an estimated 2.40,000 eggs per day by each female, which counterbalances the heavy losses in the environment. The eggs are excreted in the faeces. They become embryonated in the external environment and become infective in 2-3 weeks. On ingestion by man, the embryonated eggs hatch in the small intestine. The resulting larvae penetrate the gut wall a nd are carried to the liver and then to the lungs via the blood stream. In the lungs, they moult twice. They break through the alveolar walls and migrate into the bronchioles. They are coughed up through the trachea and then swallowed by the human host. On reaching the intestine, they become mature into adults in 60­80 days. The life span of an adult is between 6-12 months, maximum reported being 12 to 18 months . The worms can grow to be as thick as a pencil and can live for 1 to 2 years. An infection of the intestinal tract caused by the adult, Ascaris lumbricoides and clinically manifested by vague symptoms of nausea, abdominal pain and cough. Live worms are passed in the stool or vomited. Occasionally, they may produce intestinal obstruction or may migrate into the peritoneal cavity.

Causes of Ascariasis / Ascaris lumbricoides

Ascaris is a "soil-transmitted" helminth. The eggs remain viable in the soil for months or years under favourable conditions. Of the various ecological factors legulating the population of Ascaris eggs, the most important ones are the temperature, moisture, oxygen pressure and ultra-violet radiation from the sunlight . A low temperature inhibits the development of eggs. Clay soils are most favourable for the development of ascaris eggs, in contrast to moist porous soils for those of hookworms. T ransmission also comes through municipal recycling of wastewater into crop fields. This is quite common in emerging industrial economies, and poses serious risks for not only local crop sales but also exports of contaminated vegetables.

HUMAN HABITS: Seeding of the soil by ascaris eggs takes place by the human habit of indiscriminate open air defecation. It is the most important factor responsible for the widespread distribution of ascariasis in the world. Soil pollution is usually concentrated around houses where small children who have no regular habits pollute the house and surrounding areas. Infective eggs can then easily reach other children who play on the ground and contaminate their hands and food.

How Ascariasis / Ascaris lumbricoides spreads

Ascariasis is not spread directly from one person to another. To become infected, an individual has to consume the worm's eggs. By the FAECAL-ORAL route, i.e., by ingestion of infective eggs with food or drink. Foods that a re eaten raw such as salads and vegetables readily convey the infection, and so is polluted water. Other means of spread are by fingers contaminated with soil or by ingestion of contaminated soil (pica) as usually happens in the case of children playing with soil. There is increasing evidence that dust may play an important role in the dissemination of ascaris in arid areas.

Diagnosis of Ascariasis / Ascaris lumbricoides

Pulmonary: asthma, pneumonia, aspergillosis, strongyloidiasis, hookworm, or other parasitic infections. The intestinal phase may resemble a variety of gastrointestinal problems (also see complications above). Postprandial dyspepsia may appear as duodenal ulcar, hiatal hernia, pancreatic or gall bladder disease. Your health care provider will ask you to provide stool samples for testing. Some people notice infection when a worm is passed in stool or is coughed up. If this happens, bring in the worm specimen to your health care provider for diagnosis. There is no blood test used to diagnose an ascarid infection. A doctor can diagnose the infection by finding characteristic eggs in the stool.

Prevention of Ascariasis/ Ascaris lumbricoides

Methods based on primary prevention are the most effective in interrupting transmission. These are:

sanitary disposal of human excreta to prevent or reduce faecal contami nation of the soil, provision of safe drinking water, food hygiene habits, and health education of the community in the use of sanitary latrines, personal hygiene and changing behavioural patterns. Prevention to be effective must take into consideration the life cycle of the parasite and the peculiar ecological, social and cultural circumstances that prevail in a community. Food dropped on the floor should never be eaten without washing or cooking, particularly in endemic areas. Vegetables originating from third-world countries should always be washed thoroughly before consumption.

Treatment of Ascariasis/ Ascaris lumbricoides

Treatment includes medications that kill intestinal parasitic worms such as albendazole or mebendazole. If there is a blockage of the intestine caused by a large number of worms, another medication can make the worms relax and pass through the intestine. This will relieve the obstruction.

Some recent studies exist in the medical literature suggesting that sun-dried papaya seeds may reduce infections by a large factor. The adult dosage is one tablespoon of the seed powder in a glass of sugar water once a week for two weeks. The sugar makes the bitter taste palatable and acts as a laxative.

General home care in Ascariasis/ Ascaris lumbricoides

If your child has ascariasis, the medication prescribed should be administered accordingly. The following precautions are recommended to prevent reinfection:

• Ensure that your child washes her hands properly, particularly after using the bathroom and before eating.
• Have your pets checked for worms regularly.
• Keep your child's fingernails short and clean.
• Sterilize any contaminated clothing, pajamas, and bedding.
• Evaluate the source of your child's infection. Additional sanitation measures in or around your home may be necessary.