Mycobacterium Leprae
Mycobacterium Leprae Disease
In 1981, a World Health Organization (WHO) Study Group recommended multidrug therapy (MDT). MDT consists of 3 drugs: dapsone, rifampicin and clofazimine and this drug combination kills the pathogen and cures the 
patient.Since 1995, WHO provides free MDT for all patients in the world, initially through the drug fund provided by the Nippon Foundation and since 2000, through the MDT donation provided by Novartis and the Novartis Foundation for Sustainable Development.
Causes
Leprosy is caused by the organism Mycobacteriumleprae. It is not very contagious (difficult to transmit) and has a long incubation period (time before symptoms appear), which makes it difficult to determine where or when the disease was contracted. Children are more susceptible than adults to contracting the disease.
Leprosy has two common forms, tuberculoid and lepromatous, and these have been further subdivided. Both forms produce sores on the skin, but the lepromatous form is most severe, producing large, disfiguring lumps and bumps ( nodules).
All forms of the disease eventually cause nerve damage in the arms and legs, which causes sensory loss in the skin and muscle weakness. People with long-term leprosy may lose the use of their hands or feet due to repeated injury resulting from lack of sensation.
Leprosy is common in many countries worldwide, and in temperate, tropical, and subtropical climates. Approximately 100 cases per year are diagnosed in the United States. Most cases are limited to the South, California, Hawaii, and U.S. island possessions.
Effective medications exist, and isolation of victims in “leper colonies” is unnecessary. The emergence of drug-resistant Mycobacterium leprae, as well as increased numbers of cases worldwide, has led to global concern about this disease.
Background
Leprosy is a chronic granulomatous disease principally affecting the skin and peripheral nervous system. Leprosy is caused by infection with Mycobacterium leprae. Although much improved in the last 25 years, knowledge of the pathogenesis, course, treatment, and prevention of leprosy continues to evolve. The skin lesions and deformities were historically responsible for the stigma attached to leprosy. However, even with proper multidrug therapy (MDT), the consequent sensory and motor damage results in the deformities and disabilities associated with leprosy.
The earliest description of leprosy comes from India around 600 BCE. Leprosy was then described in the Far East around 400 BCE. In the fourth century, leprosy was imported into Europe, where its incidence peaked in the 13th century. Leprosy has now nearly disappeared from Europe. Affected immigrants spread leprosy to North America.
Armauer Hansen discovered M leprae in Norway in 1873. M leprae was the first bacillus to be associated with human disease. Despite this discovery, leprosy was not initially thought to be an infectious disease.
In 2009, the discovery of a new cause of leprosy, Mycobacterium lepromatosis, was announced. Genetically, M leprae and M lepromatosis are very similar, but M lepromatosis causes the diffuse form lepromatous leprosy found in Mexico and the Caribbean.
Humans are the primary reservoir of M leprae. Animal reservoirs of leprosy have been found in 3 species: 9-banded armadillos, chimpanzees, and mangabey monkeys.
Calling your health care provider
Call your health care provider if you have symptoms of leprosy, especially if you’ve had contact with someone who has the disease. Cases of leprosy in the United States need to be reported to the Centers for Disease Control and Prevention.