Q.90 Which of the following is/are the causative agent(s) of Filariasis?
(A) Wuchereria bancrofti
(B) Leishmania donovani
(C) Brugia malayi
(D) Trypanosoma gambiense
Correct Answer: (A) and (C)
Filariasis, specifically lymphatic filariasis, is caused by the filarial nematodes Wuchereria bancrofti and Brugia malayi. These parasites infect the lymphatic system via mosquito bites, leading to symptoms like elephantiasis. Options (B) and (D) cause unrelated diseases and are not filarial worms.
Option Analysis
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(A) Wuchereria bancrofti: Primary causative agent, responsible for ~90% of cases worldwide, transmitted by Culex, Aedes, and Anopheles mosquitoes.
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(B) Leishmania donovani: Protozoan parasite causing visceral leishmaniasis (kala-azar), transmitted by sandflies; affects spleen, liver, and bone marrow, not lymphatic filariasis.
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(C) Brugia malayi: Causative agent for ~10% of cases, mainly in Southeast Asia, transmitted by Mansonia and Aedes mosquitoes.
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(D) Trypanosoma gambiense: Protozoan causing African sleeping sickness (trypanosomiasis), transmitted by tsetse flies; leads to neurological damage, unrelated to filariasis.
Lymphatic filariasis, commonly known as filariasis, ranks among neglected tropical diseases targeted by WHO for elimination. The primary causative agents of filariasis are filarial nematodes transmitted by mosquitoes, causing lymphatic obstruction and chronic swelling. This article breaks down the key parasites, explains exam options, and aids CSIR NET aspirants in mastering parasitology.
Causative Agents of Filariasis
Wuchereria bancrofti dominates globally, causing Bancroftian filariasis in Africa, Asia, and the Pacific. Brugia malayi drives Brugian filariasis in Southeast Asia, including India. Both reside in lymphatics as adults, releasing microfilariae into blood for mosquito uptake.
Non-Causative Parasites
Leishmania donovani triggers kala-azar via sandfly bites, invading macrophages without lymphatic involvement. Trypanosoma gambiense induces sleeping sickness through tsetse flies, progressing to CNS damage. These protozoans differ fundamentally from nematodes.
Transmission and Symptoms
Mosquitoes inject third-stage larvae during bites; adults mature in 6-12 months. Acute symptoms include fever and lymphangitis; chronic cases show lymphedema or hydrocele. Diagnosis uses blood smears for microfilariae, showing nocturnal periodicity.
Prevention for CSIR NET
Mass drug administration with diethylcarbamazine targets causative agents of filariasis. Vector control via nets reduces transmission. Practice MCQs: Filariasis agents are nematodes (A, C); protozoans (B, D) cause leishmaniasis/trypanosomiasis.
