Leprosy is caused by Mycobacterium leprae, which is a slow-growing bacteria type, according to WebMD. Leprosy is sometimes referred to as Hansen's disease, and has been around since ancient times when it was feared in India, Egypt and China for the disfiguring sores it causes on the skin, and the nerve damage it inflicts on the legs and arms.
Generally, leprosy affects the nerves outside the spinal cord, the brain and the skin, but it can also affect the lining of the nose and the eyes. Nerve damage caused by leprosy can bring on muscle weakness and loss of feeling in the limbs. After infection, WebMD notes that it takes as long as 5 years for leprosy symptoms to appear, but some people who contract leprosy do not develop any symptoms at all until 20 years after infection. It is this extended incubation period that creates difficulty for medical professionals to determine when and where an individual contracts it.
Most leprosy cases are treatable with antibiotics. Surgery plays an important role in recovery following leprosy once negative skin smears indicate that antibiotic treatment was successful, according to MedicineNet. The goal of most surgeries following leprosy is to restore neural and limb functionality.