When did leprosy appear, what is it caused by, is it curable...?

That is one really big question, I can help you with a few of them. Leprosy is caused by Mycobacterium leprae. The bacterium prefers lower temperature than our body temp [30 C] so it proliferates in the periphery/extremities [limbs and appendages]. It is often found in poorer regions of the world where the antibiotics used to treat the infection are unavailable. Treatment is a series of antibiotics that can take years. There are two forms, tuberuloid leprosy and lepromatous leprosy. These determined by the response our bodies immune system has to the infection. If the body initially has a cell mediated response, the infection should become tuberculoid leposy. [granulomas surrounded by lymphocytes, the infection is contained]. If the Immune response was a humoral, antibody based response [b-cells instead of t-cells] then the infection will not be contained. These cases the infection should be lepromatous leprosy, the one that is more widely known. The infection spreads through the body and the infection will eventually consume the body if treatment is not sought. Below is an excerpt from the World Health Organization website.[link below] I thought these figures could help answer your question..... According to official reports received from 115 countries and territories, the global registered prevalence of leprosy at the beginning of 2006 stood at 219,826 cases, while the number of new cases detected during 2005 was 296,499 (excluding the small number of cases in Europe). The number of new cases detected globally has fallen by more than 111,000 cases (a 27% decrease) during 2005 compared with 2004. During the past four years, the global number of new cases detected has continued to decrease dramatically, by about 20% per year. Most previously highly endemic countries have now reached elimination, and those few that remain are very close to eliminating the disease. However, pockets of high endemicity still remain in some areas of Angola, Brazil, Central African Republic, Democratic Republic of Congo, India, Madagascar, Mozambique, Nepal, and the United Republic of Tanzania. These countries remain highly committed to eliminating the disease, and continue to intensify their leprosy control activities.

It is in the BIBLE - Leprosy bible quote (Luke 17:11-19) Although leprosy had been known to affect people for centuries, Gerhard Hansen, a Norwegian physician is widely recognized as the person who first identified the bacterium Mycobacterium leprae as the cause of the disease. Hansen concluded on the basis of epidemiological studies that leprosy had a single specific cause. Between 1870 and 1871, Hansen travelled to Bonn and Vienna to gain the training necessary for him to prove his hypothesis. In 1873, he published the discovery of rod-shaped bodies (Mycobacterium leprae) in tissue samples from patients with leprosy and asserted that they were the disease agents. At the time, the disease was thought to be inherited and his result did not rapidly gain acceptance. In 1879, Hansen gave tissue samples to Albert Neisser who successfully stained the bacteria and announced his findings in 1880, claiming to have discovered the disease-causing organism. There are still a few leper colonies around the world, in countries such as India and the Philippines. Western humanitarian and church organizations regularly send relief supplies, including handmade "leper bandages"; bandages knitted or crocheted out of cotton, for greater breathability and durability than traditional gauze. The bandages can also be washed, sterilized and reused, making them more cost-effective as well. As an aside: did you see the Eugene Smith photos from the lepracy collony in Africa -- WOW !!!