Question

The fourth stage juvenile of Ascariasis is found in its host
(a) Intestine
(b) Lungs
(c) Pharynx
(d) Liver

Answer 1

Hint: Young immature undeveloped larvae of Ascaris is formed after the 3rd moulting inside the respiratory organs of humans.

Complete answer:
The shell of ascariasis gets dissolved in the small intestine and 2nd stage larvae are released. Now it undergoes extraintestinal migration. This 2nd stage larvae enter into the liver and from there it moves into the lungs. In the lungs, 2nd stage undergoes 2nd moulting and forms 3rd stage larvae and it undergoes 3rd moulting and forms 4th stage larvae in the alveoli. It is the undeveloped stage.

Additional Information: - In the small intestine of man copulation of Ascaris lumbricoid takes place resulting in 2 lakhs eggs per day. Each egg is surrounded by a protein coat with a rippled surface hence the eggs are called mammillated eggs.
- These eggs are passed out along with the faecal matter and inside the egg 1st rhabditiform larvae which undergo 1st moulting resulting in the information of 2nd rhabditiform larvae.
- these larvae enter the human body via contaminated food and water.
- In the small intestine, the shell gets dissolved and 2nd stage larvae are released which undergo extraintestinal migration.
- This 2nd stage larvae enters into the liver and from there it moves into the lungs via pulmonary arteries.
- In alveoli of lungs, it undergoes 2nd moulting and forms 3rd stage larvae and it undergoes 3rd moulting and forms 4th stage larvae in the alveoli.
- it leaves the alveoli and reaches the small intestine where it undergoes 4th moulting(final) and becomes a young one that attains sexual maturity within 8 to 10 weeks.
So, the correct answer is ‘lungs;

Note: -A heavy infection causes nutritional deficiency and severe abdominal pain.
-If the number of worms is less then there are no symptoms of ascariasis.
-2nd rhabditiform larvae are the infective stage of ascariasis.