Leprosy, also known as Hansen's disease, is a chronic infection caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Initially infections are without symptoms and typically remain this way for 5 to as long as 20 years.Symptoms that develop include granulomas of the nerves, respiratory tract, skin, and eyes.Leprosy is caused by a slow-growing type of bacteria called Mycobacterium leprae (M. leprae). Leprosy is also known as Hansen's disease, after the scientist who discovered M. leprae in 1873.The disease was once feared as a highly contagious and devastating disease. Now, however, the disease is very rare and easily treated. Early diagnosis and treatment usually prevent disability related to the disease.Today, about 180,000 people worldwide are infected with leprosy, according to the World Health Organization, most of them in Africa and Asia. About 200 people are diagnosed with leprosy in the U.S. every year, mostly in the South, California, Hawaii, and some U.S. territories.
