Hansen's disease (Hansen's disease) is a chronic infectious illness that predominantly affects the peripheral nerves, skin, upper respiratory tract, eyes, and nasal mucosa (lining of the nose). Mycobacterium leprae, a bacillus (rod-shaped) bacteria, causes the illness. Leprosy is not contagious; it cannot be spread from person to person. Leprosy is curable now with multidrug therapy but must be started early in the course of the disease. There are two main types of leprosy: tuberculoid leprosy and lepromatous leprosy. In people with tuberculoid leprosy, the immune system controls the M. leprae infection and destroys the bacteria while maintaining the ability to fight other infections. This type of leprosy is also called "tuberculoid" or "indurated" leprosy. People with this type of leprosy do not get sick or sick for a short time and their symptoms go away without any treatment. However, people with lepromatous leprosy don't produce enough antibodies against the M. leprae bacteria and so they develop multiple small lesions throughout their bodies which cause pain, nerve damage, and sometimes blindness. People with this type of leprosy need long-term treatment with antibiotics and sometimes surgery to remove damaged tissue.