I am really happy to know that you are interested in knowing the leprosy
and its history. It is long long and very much diverse thing which can not be covered in a single mail.
Even for me it took 10 years to understand your matter of concern and still I am in precess of learning the same. For the same it would be pretty difficult to tell you what exactly is your choice of matter could be. I suggest you to go to Wikipedia and read the matter according to your choice of interest.