Leprosy is caused by a bacteria called Mycobacteria leprae and Mycobacterium lepromatosis. These organisms cause this very horrible debilitating disease where basically one gets deformities in the skin, eyes, limbs, and nerves. The bacteria is believed to be contracted through the respiratory route just like it’s “cousin” Mycobacterium tuberculosis which causes TB (tuberculosis).
Leprosy has a very interesting history. It is one of those diseases that have been documented over centuries including in the bible. Historically, the treatment for leprosy was isolating individuals with the disease to minimise spread of the infection (even though it is not that contagious compared to TB). The same was true for TB where people were also isolated in what the called sanatoriums.
Leprosy is a good example of a disease whose burden, number of new cases every year, has decreased over time. Mainly due to good treatment and early diagnosis. Though in countries like India it is still a major problem.