Question

The disease caused by roundworm Ascaris is transmitted through:
(a) Contaminated food
(b) Contaminated water
(c) Both A and B
(d) Sneezing

Answer 1

Hint: Ascaris infection or Ascariasis can be caused if the eggs of the worm are ingested accidentally.

Complete answer: Ascaris belongs to the phylum Aschelminthes.
These are soil-transmitted helminth (STH) worms.

These are commonly called hookworms/whipworms and are parasitic in nature.
Ascaris worms live in the human intestine and their eggs are passed in the faeces of infected people. If the person defecates in an open area or the faeces containing eggs are used as fertilizer, eggs can get transferred to the soil, dirt etc.

Unfertilized eggs may not be as harmful, but fertile eggs become larvae and become infective. The fertilized eggs if ingested accidentally can cause Ascariasis. The larvae hatch and reach duodenum, then to systemic circulation.
They reach lungs where larvae mature. After they are swallowed again, the larvae reach the small intestine and become adults.
Reproduction occurs there and eggs are passed along with faeces again. The whole process can take from a few months to even a year or so.
From the lifecycle of the worm, it is clear that the main way of infection is through ingestion of eggs.
Consumption of contaminated food, water, unpeeled, unwashed raw fruits and vegetables can lead to infection.

So, the correct option is ‘both A and B’.

Note: Ascaris lumbricoides is the most common infective agent.
Humans can also get infection from other species e.g. Ascaris suum