Question

Consider the following statements Assertion (A): Due to the infection of Wuchereria, the affected part shows swelling. Reason (R): The live and dead filarial worms block the lymph flow, which leads to lymphoedema.

• A. Both (A) and (R) are true, (R) is the correct explanation of (A)
• B. Both (A) and (R) are true, (R) is not the correct explanation of (A)
• C. (A) is true, but (R) is false
• D. (A) is false, but (R) is true

Hint:

Elephantiasis results from blockage of lymphatic vessels by filarial worms, causing severe lymph accumulation and swelling.

Answer 1

The Correct Option is A

Concept: Filariasis or elephantiasis is caused by filarial worms such as Wuchereria bancrofti and Wuchereria malayi. These parasites inhabit lymphatic vessels of humans.

Step 1: Analyze the Assertion. Individuals infected by Wuchereria often develop abnormal swelling in limbs, scrotum or other body parts. This swelling is a characteristic symptom of elephantiasis. Hence Assertion (A) is true.

Step 2: Analyze the Reason. Adult filarial worms live in lymphatic vessels. Both living and dead worms obstruct the normal flow of lymph. This blockage causes accumulation of lymph fluid in tissues leading to: \[ \text{Lymphoedema} \] which ultimately produces swelling. Hence Reason (R) is true.

Step 3: Relationship between Assertion and Reason. The swelling mentioned in Assertion occurs precisely because lymphatic drainage is blocked by the worms. Therefore the Reason correctly explains the Assertion.

Step 4: Final conclusion. Both statements are true and Reason correctly explains Assertion. \[ \boxed{\text{Both true and Reason correctly explains Assertion}} \] Hence option (A) is correct.