Question

Arrange in order, the sequence of events in the infective cycle of Wuchereria bancrofti:
(i) Parasitic worms enter the human through an infected mosquito.
(ii) Microfilariae are produced by the female parasite in the lymph nodes.
(iii) Microfilariae circulate in the superficial parts of the body at night.
(iv) Mosquito bites an infected person and transfers the parasites to a healthy person in the next blood meal.

• A. i, ii,iii,iv
• B. iv,ii,iii,i
• C. i,iv,ii,iii
• D. iv ,i,ii,iii

Answer 1

The correct option is A i, ii,iii,iv

Wuchereria bancrofti is the infectious agent in lymphatic filariasis. Mainly the parasite is found where mosquitoes are found. Human beings are the only definitive host for this parasite. Adult worms reside in the lymph nodes. The swollen lymph nodes of the patient contain the parasitic worms. The female parasite gives rise to the larvae called microfilariae. The microfilariae are found mainly in the peripheral blood and can be found at peak amounts from 10 p.m. to 4 a.m. They migrate between the deep and the peripheral circulation. During the day, they are present in the deep veins, and during the night, they migrate to the peripheral circulation. When a mosquito bites an infected person, it takes in the microfilariae, and transfers it to a healthy person during the next blood meal.