Question

Name the causative agent of Elephantiasis.

Answer 1

Hint: Elephantiasis is a late complication of Filariasis. It is characterized by gross overgrowth and thickening of the skin and firm and rubbery enlargement of the affected part, regeneration, and atrophy of muscles in the affected part. Filariasis is the name given to a group of tropical diseases, caused by nematode worms, called filarial worms.

Complete answer:
Wuchereria bancrofti is the common filarial worm. The life cycle of Wuchereria bancrofti is completed in man and female Culex or Aedes mosquito. Man is the definitive or primary host, and the mosquito is the intermediate host, which serves as a vector. Mating and fertilization occur in human lymphatics. Female is ovoviviparous. So, early embryonic development occurs in her body. On completion of this development, she discharges a large number of juvenile worms known as microfilariae. They pass through the thoracic duct and pulmonary blood capillaries and reach the superficial blood vessels. Microfilariae are able to undergo further development only in the mosquito. Their transmission to man and mosquito is inoculative, occurring when the mosquito bites a human being for its blood meal. In the mosquito, each of them undergoes partial development and transforms into an infective form. Then it undergoes a period of development and transforms into a short and actively moving infective form called filariform larva. The filariform larva enters the bloodstreams of the mosquitoes and reaches the proboscis of the mosquito for transmission to a new human host.

Additional Information: -Chemotherapy of infected persons using anti-microfilarial drugs would reduce the risk of infection
-Isolation of infected persons from mosquitoes to check the spread of malaria.
-Destruction of mosquitoes using insecticides and clearing of mosquito breeding grounds.- Culex mosquito breed in swamps having floating weeds. So the removal of aquatic weeds is effective in controlling Culex.
-Fish farming is very effective in controlling water weeds and mosquito larvae.

Note: -The infection of W. bancrofti is of two kinds, asymptomatic and symptomatic. In the former detectable clinical manifestations are absent, though it is characterized by detectable Microfilariae and antigenemia.
-Symptomatic Filariasis is characterized by a wide spectrum of clinical manifestations. It’s earlier symptoms include headache, nausea, vomiting, pruritus, nettle rash, etc.
- Late symptoms of Filariasis include inflammation of lymph vessels, inflammation of the lymph gland, rupture of lymph vessels, and leakage of lymph.