Mycobacterium leprae
Leprosy, also known as Hansen's Disease, is caused by a bacillus, "Mycobacterium leprae". It is a chronic disease with an incubation period of up to five years. Symptoms often include irritation or erosion of the skin, and effects on the peripheral nerves, mucosa of the upper respiratory tract and eyes. The most common sign of leprosy are pale reddish spots on the skin that lack sensation.