In the context of human diseases, 'Elephantiasis' is a chronic condition characterized by the severe swelling of limbs and genitals. It is caused by the filarial worm: MCQ with Answer and Explanation

Elephantiasis, or lymphatic filariasis, is caused by parasitic nematode worms, primarily Wuchereria bancrofti (responsible for about 90% of cases), Wuchereria malayi, and Brugia timori. These worms are transmitted by mosquitoes (like Culex). The adult worms lodge in the lymphatic vessels, causing severe inflammation, blockage, and damage to the lymphatic system. This leads to the accumulation of lymph fluid and massive, disfiguring swelling (edema) of the limbs, genitals, and breasts, resembling an elephant's skin and legs.