Ascariasis
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Direct answer
Ascariasis is a helminthic disease caused by the intestinal roundworm Ascaris, acquired when embryonated eggs are swallowed in contaminated food and water. The adult worms inhabit the human intestine and produce internal bleeding, muscular pain, fever, anaemia and, in heavy infections, blockage of the intestinal passage. It is a disease of poor sanitation, controlled by clean food, safe water and deworming under medical supervision.
What you must remember
- Causative organism: Ascaris lumbricoides, the large intestinal roundworm — an endoparasitic helminth of humans.
- Transmission: food and water contaminated with embryonated eggs shed in the faeces of infected persons; unwashed vegetables grown in contaminated soil are a common vehicle.
- Habitat: the small intestine of the host, where adult worms live and grow to considerable length.
- Symptoms: internal bleeding, muscular pain, fever, anaemia, and blockage of the intestinal passage when worms aggregate in large numbers.
- Effects of heavy load: malnutrition and impaired growth in children, since the worms feed on the host's digested food.
- Prevention: washing hands before meals, cleaning and cooking vegetables, safe drinking water, sanitary disposal of faeces, and periodic deworming as advised in public-health programmes.
- Classification: soil-transmitted helminthiasis — grouped with filariasis among worm diseases, but transmitted by ingestion rather than by an insect vector.
Common confusion
Ascariasis is often muddled with filariasis because both are helminth infections, but their routes differ completely: Ascaris enters through the mouth in contaminated food and water and lives in the intestine, whereas Wuchereria is injected by mosquitoes and lodges in lymphatic vessels. The symptom sets also differ — anaemia and intestinal blockage for ascariasis versus lymphatic swelling and elephantiasis for filariasis.
Exam-focused takeaway
NEET-UG tests ascariasis in the pathogen table as a helminth disease spread by contaminated food and water, with symptoms of internal bleeding, muscular pain, fever, anaemia and intestinal blockage. Match-the-following items pair Ascaris with the intestine, and statement questions contrast egg-borne ingestion with mosquito-borne filariasis. Remember it as the worm you swallow, not the worm you are injected with.
Frequently asked questions
Which parasite causes ascariasis?
The intestinal roundworm Ascaris lumbricoides, an endoparasitic helminth living in the human intestine.
How is ascariasis acquired?
By swallowing embryonated eggs of Ascaris present in contaminated food and water.
What symptoms does ascariasis produce?
Internal bleeding, muscular pain, fever, anaemia, and in heavy infections, blockage of the intestinal passage.
Where do the adult worms live?
In the intestine of the infected person, where they feed on the host's food and can aggregate to obstruct the lumen.
How can ascariasis be prevented?
Through sanitary disposal of human faeces, washing and cooking vegetables, safe drinking water, hand washing and periodic deworming.