Leprosy is a bacterial disease of the skin and nerves in the hands and feet and the mucus membranes of the nose, eyes and respiratory tract. It is also called Hansen's disease. It is usually found in tropical climates.
The main symptom of leprosy is the loss of feeling on a patch of skin that is reddish or copper-colored. These patches can show up any where on the body and don't itch or hurt but they can become infected leading to disfigurement and disabilities. If it's detected early and treated, patients won't have disabilities from the disease.
Leprosy is caused by the bacillus, Mycobacterium leprae. It's a rod shaped, acid-fast bacillus that multiplies very slowly. It has never been grown in bacteriologic media or cell culture. There are 2 main kinds of leprosy: Lepromatous, the more common form in which the disease spreads up the nerves but doesn't stick to them, and Tuberculoid, in which it sticks to the nerves. They are classified by the 5-scale TT-LL System, with non-infectious leprosy at the low end of the scale and multibacillary leprosy at the high end. The bacillus attacks the nerve's Schwann Cells, which causes that part of the body to lose feeling. .
Leprosy is transmitted through droplets from the mouth and nose or possibly through open sores, usually through a lot of close contact with someone that has leprosy but is not being treated by drugs for it. It's not highly contagious. Most people have neutral immunity to it and not many people get the disease.
Leprosy is one of the oldest diseases know to man. It was first accounted for in India around 600 B.C. It was spread to Europe from troops coming back from wars. In 1873, G. A. Hansen of Norway identified the bacillus that causes leprosy. In 1940 drug treatment for the disease began, before then patients were isolated to keep the disease from spreading. In modern times the disease is mainly in Africa, India, South America and Southeast Asia.