Question

Which parasitic worm is responsible for causing lymphatic filariasis?

• A. $ \text{Wuchereria bancrofti} $
• B. $ \text{Brugia malayi} $
• C. $ \text{Onchocerca volvulus} $
• D. $ \text{Ancylostoma duodenale} $

Hint:

Wuchereria bancrofti is the primary causative organism for lymphatic filariasis — focus on mosquito-borne helminths for GPAT.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
We need to name the parasitic worm that causes lymphatic filariasis, a disease in which the lymph vessels get blocked and body parts, especially the legs and genitals, swell up.

Step 2: Key Concept:
The organism responsible for a filarial disease can usually be worked out from its vector and the part of the body its microfilariae and adult worms prefer.

Step 3: Detailed Explanation:
Wuchereria bancrofti is transmitted by the bite of infected Culex, Anopheles, or Aedes mosquitoes. The larvae mature into adult worms inside the lymphatic vessels, where they physically obstruct lymph drainage and cause chronic swelling, thickened skin, and in advanced cases, elephantiasis. This species is found across large parts of Africa, Asia, and the Pacific and is by far the most common cause of lymphatic filariasis.
Brugia malayi behaves in a broadly similar way and is also carried by mosquitoes, but it is confined mainly to South and Southeast Asia and causes far fewer cases overall.
Onchocerca volvulus is spread by the black fly, not mosquitoes, and its worms settle under the skin rather than in the lymphatics, producing river blindness instead.
Ancylostoma duodenale is a soil transmitted hookworm that enters through the skin of the feet and settles in the intestine, causing blood loss and anemia, with no lymphatic involvement whatsoever.

Step 4: Final Answer:
Wuchereria bancrofti is the worm responsible for lymphatic filariasis.