question: What disease characterized by the extreme swelling of the limbs is caused by infection with a type of roundworm?
distractor3: fibrosis
distractor1: pulmonary edema
distractor2: gigantism
correct_answer: elephantiasis
support: Roundworms can be free-living organisms, but they are probably best known for their role as significant plant and animal parasites. Most Nematodes are parasitic, with over 16,000 parasitic species described. Heartworms, which cause serious disease in dogs while living in the heart and blood vessels, are a type of roundworm. Roundworms can also cause disease in humans. Elephantiasis, a disease characterized by the extreme swelling of the limbs ( Figure below ), is caused by infection with a type of roundworm.