their mental well-being. The social stigma may contribute to problems obtaining employment, financial difficulties, and social isolation. Efforts to reduce discrimination and reduce the stigma surrounding leprosy may help improve outcomes for people with leprosy. Epidemiology In 2018, there were 208,619 new cases of leprosy recorded, a slight decrease from 2017. In 2015, 94% of the new leprosy cases were confined to 14 countries. India reported the greatest number of new cases (60% of reported cases), followed by Brazil (13%) and Indonesia (8%). Although the number of cases worldwide continues to fall, there are parts of the world where leprosy is more common, including Brazil, South Asia (India, Nepal, Bhutan), some parts of Africa (Tanzania, Madagascar, Mozambique), and the western Pacific. About 150 to 250 cases are diagnosed in the United States each year. In the 1960s, there were tens of millions of leprosy cases recorded when the bacteria started to develop resistance to dapsone, the most common treatment option at the time. International (e.g., the WHO's "Global Strategy for Reducing Disease Burden Due to Leprosy") and national (e.g., the International Federation of Anti-Leprosy Associations) initiatives have reduced the total number and the number of new cases of the disease. Disease burden The number of new leprosy cases is difficult to measure and monitor because of leprosy's long incubation period, delays in diagnosis after onset of the disease, and lack of medical care in affected areas. The registered prevalence of the disease is used to determine disease burden. Registered prevalence is a useful proxy indicator of the disease burden, as it reflects the number of active leprosy cases diagnosed with the disease and receiving treatment with MDT at a given point in time. The prevalence rate is defined as the number of cases registered for MDT treatment among the population in which the cases have occurred, again at a given point in time. History Historical distribution Using comparative genomics, in 2005, geneticists traced the origins and worldwide distribution of leprosy from East Africa or the Near East along human migration routes. They found four strains of M. leprae with specific regional locations: Monot et al. (2005) determined that leprosy originated in East Africa or the Near East and traveled with humans along their migration routes, including those of trade in goods and slaves. The four strains of M. leprae are based in specific geographic regions where each predominantly occurs: strain