Q.15 An organism that causes obstruction of lymphatic system in humans is ____.
(A) Borrelia burgdorferi
(B) Brucella abortus
(C) Yersinia pestis
(D) Wuchereria bancrofti
Wuchereria bancrofti is the correct answer (D).
This filarial nematode causes lymphatic filariasis, leading to chronic obstruction of the human lymphatic system through adult worms lodging in lymph vessels, causing inflammation, scarring, and lymphedema (elephantiasis).
Option Analysis
Borrelia burgdorferi (A): This spirochete bacterium causes Lyme disease, transmitted by ticks. It can disseminate to lymph nodes, inducing temporary lymphadenopathy (enlarged nodes) during early infection, but does not cause obstruction or chronic lymphatic blockage.
Brucella abortus (B): This bacterium primarily affects livestock, causing brucellosis with abortions in cattle and flu-like symptoms in humans. It spreads via bloodstream and lymphatics but leads to transient lymph node involvement, not obstructive damage.
Yersinia pestis (C): The plague bacterium causes bubonic plague with acute, painful swelling of lymph nodes (buboes) due to rapid bacterial multiplication. This results in node destruction and suppuration, not chronic lymphatic obstruction.
Introduction to Lymphatic Filariasis
The organism that causes obstruction of lymphatic system in humans is Wuchereria bancrofti, a thread-like nematode responsible for 90% of lymphatic filariasis cases worldwide. Mosquitoes transmit microfilariae, which mature into adults that block lymph flow, leading to severe swelling known as elephantiasis. This neglected tropical disease affects over 120 million people, emphasizing its public health impact.
Disease Mechanism
Adult Wuchereria bancrofti worms reside in lymphatic vessels, provoking immune responses that damage vessel walls and valves. This chronic obstruction prevents lymph drainage, causing edema in limbs, genitals, and breasts. Unlike bacterial infections, the filarial blockage is progressive and irreversible without intervention.
Transmission and Risk Factors
Infection occurs via bites from Culex, Anopheles, or Mansonia mosquitoes carrying infective larvae. Endemic in tropical regions like India, Africa, and Asia, children acquire it early, with symptoms appearing years later. Over 1.3 billion people remain at risk globally.
Prevention and Treatment
Mass drug administration with diethylcarbamazine, ivermectin, and albendazole interrupts transmission. Vector control and hygiene reduce morbidity, aiming for WHO elimination by 2030. Early treatment prevents chronic obstruction.
