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 WHOs "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 leprosys 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.
This molecular test alone is not sufficient to diagnose a person, but this approach may be used to identify someone who is at high risk of developing or transmitting leprosy such as those with few lesions or an atypical clinical presentation. Classification
Several different approaches for classifying leprosy exist. There are similarities between the classification approaches. The World Health Organization system distinguishes "paucibacillary" and "multibacillary" based upon the proliferation of bacteria. ("pauci-" refers to a low quantity.) The Ridley-Jopling scale provides five gradations. The ICD-10, though developed by the WHO, uses Ridley-Jopling and not the WHO system. It also adds an indeterminate ("I") entry. In MeSH, three groupings are used. Leprosy may also occur with only neural involvement, without skin lesions. Prevention
Early detection of the disease is important, since physical and neurological damage may be irreversible even if cured. Medications can decrease the risk of those living with people who have leprosy from acquiring the disease and likely those with whom people with leprosy come into contact outside the home. The WHO recommends that preventive medicine be given to people who are in close contact with someone who has leprosy. The suggested preventive treatment is a single dose of rifampicin (SDR) in adults and children over 2 years old who do not already have leprosy or tuberculosis.