Elephantiasis. Clinical view from the front of the swollen lower left leg of a patient with elephantiasis, also known as lymphatic filariasis. This disease is caused by parasitic nemotode worms transmitted in larval form by the bite of mosquitoes. The larvae develop into adult worms (macrofilariae) that lodge in and block the lymphatic system. This causes lymph to accumulate in the limbs, a form of lymphoedema. Elephantiasis is rarely fatal, but causes widespread suffering in tropical regions. Treatment involves drug therapy and rigorous hygiene to prevent skin infections.