What is Leprosy?

Leprosy or Hansen's disease (HD), named after physician Gerhard Armauer Hansen, is a chronic disease caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Leprosy is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions are the primary external sign. Left untreated, leprosy can be progressive, causing permanent damage to the skin, nerves, limbs and eyes. Contrary to myth, leprosy does not cause body parts to fall off, although they can become numb and/or diseased as a result of the disease.

A 24-year-old man infected with leprosy.