Q.Though filariasis is not fatal, but the disease in humans is responsible for considerable suffering, gross deformities and disability. Write the scientific name of any two helminth worms causing the disease and state two chronic manifestations of filariasis.

Concept: Filariasis is a parasitic disease caused by nematode (roundworm) helminths transmitted by mosquitoes, leading to lymphatic damage and chronic deformities.

Reasoning:

1. The causative helminths are thread-like filarial worms belonging to the genera Wuchereria and Brugia.
2. Chronic infection blocks lymphatic vessels, causing fluid accumulation and tissue thickening.
3. Common chronic manifestations include elephantiasis (gross swelling of limbs or genitals) and hydrocele (scrotal swelling in males).

Answer:

Two helminth worms: Wuchereria bancrofti and Brugia malayi.

Two chronic manifestations: Elephantiasis (lymphoedema of limbs/scrotum) and hydrocele.

The Concept: Why These Worms Cause Such Damage

Filariasis is a parasitic disease caused by thread-like roundworms (nematodes) that live in the human lymphatic system. The lymphatic system is our body's drainage network — it collects excess fluid from tissues and returns it to the blood, and it also houses immune cells. When filarial worms block these lymphatic vessels, fluid cannot drain properly. Over years of repeated infection, the blockage becomes permanent, leading to massive swelling and tissue damage.

The two most important species responsible for human filariasis are Wuchereria bancrofti (causing about 90% of cases) and Brugia malayi (common in Southeast Asia). Both are transmitted by mosquito bites — the mosquito picks up microscopic larvae (called microfilariae) from an infected person's blood and injects them into a new host.

Step-by-Step Reasoning

1. Identify the causative organisms.

   The disease is caused by filarial nematodes. The two most common species are:

   • Wuchereria bancrofti
   • Brugia malayi (A third species, Brugia timori, is less common but also causes filariasis in parts of Indonesia.)

2. Understand the chronic manifestations.

   Chronic filariasis develops after years of repeated infection. The adult worms lodge in lymphatic vessels, causing inflammation and scarring. Over time, the lymphatic system becomes blocked. This leads to two hallmark chronic conditions:

   • Elephantiasis (lymphoedema): The affected limb (usually a leg, but sometimes an arm, breast, or scrotum) swells enormously because lymph fluid cannot drain. The skin becomes thick, rough, and warty — resembling an elephant's leg. This is not just swelling; it is permanent tissue damage.

   • Hydrocele: In males, fluid accumulates in the tunica vaginalis (the sac around the testis), causing scrotal swelling. This is especially common with W. bancrofti infection.

   Other chronic manifestations include chyluria (milky urine due to lymphatic fluid leaking into the urinary tract) and recurrent fevers, but the two most frequently asked in exams are elephantiasis and hydrocele.

Final Answer