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Fact sheet N°101
Updated May 2015

Key facts

  • Leprosy is a chronic disease caused by a slow multiplying bacillus, Mycobacterium leprae.
  • M. leprae multiplies slowly and the incubation period of the disease is about 5 years. Symptoms can take as long as 20 years to appear.
  • The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes.
  • Leprosy is curable.
  • Although not highly infectious, it is transmitted via droplets, from the nose and mouth, during close and frequent contacts with untreated cases.
  • Early diagnosis and treatment with multidrug therapy (MDT) remain key in eliminating the disease as a public health concern
  • Untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs and eyes.
  • Official figures from 103 countries from 5 WHO regions show the global registered prevalence of leprosy to be at 180 618 at the end of 2013; during the same year, 215 656 new cases were reported.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an acid-fast, rod-shaped bacillus. The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes.

Leprosy is curable and treatment provided in the early stages averts disability.

Multidrug therapy (MDT) treatment has been made available by WHO free of charge to all patients worldwide since 1995, and provides a simple yet highly effective cure for all types of leprosy.

Elimination of leprosy globally was achieved in the year 2000 (i.e. a prevalence rate of leprosy less than 1 case per 10 000 persons at the global level). Nearly 16 million leprosy patients have been cured with MDT over the past 20 years.

Leprosy today

Leprosy control has improved significantly due to national and subnational campaigns in most endemic countries. Integration of primary leprosy services into existing general health services has made diagnosis and treatment of the disease easy.

Detection of all cases in a community and completion of prescribed treatment using MDT are the basic tenets of the Enhanced Global Strategy for Further Reducing Disease Burden Due to Leprosy (plan period: 2011–2015).

The Strategy emphasizes the need to sustain expertise and increase the number of skilled leprosy staff, improve the participation of affected persons in leprosy services and reduce visible deformities – otherwise called Grade 2 disabilities (G2D cases) – as well as stigma associated with the disease.

National leprosy programmes for 2011–2015 now focus more on underserved populations and inaccessible areas to improve access and coverage. Since control strategies are limited, national programmes actively improve case-holding, contact tracing, monitoring, referrals and record management.

According to official reports received from 103 countries from 5 WHO regions, the global registered prevalence of leprosy at the end of 2013 was 180 618 cases. The number of new cases reported globally in 2013 was 215 656 compared with 232 857 in 2012 and 226 626 in 2011.

The number of new cases indicates the degree of continued transmission of infection in the community. A total of 13 countries reported zero cases in 2013. Global statistics show that 206 107 (96%) of new leprosy cases were reported from 14 countries and only 4% of new cases from the rest of the world. Only these 14 countries reported >1000 new cases in 2013.

Pockets of high endemicity still remain in some areas of many countries but a few are mentioned as reference: Angola, Bangladesh, Brazil, People’s Republic of China, Democratic Republic of Congo, Ethiopia, India, Indonesia, Madagascar, Mozambique, Myanmar, Nepal, Nigeria, Philippines, South Sudan, Sri Lanka, Sudan and the United Republic of Tanzania.

Brief history of the disease and treatment

Leprosy was recognized in the ancient civilizations of China, Egypt and India. The first-known written mention of leprosy is dated 600 BC. Throughout history, people afflicted have often been ostracized by their communities and families.

Although leprosy was treated differently in the past, the first breakthrough occurred in the 1940s with the development of the drug dapsone, which arrested the disease. But the duration of the treatment was many years and even a lifetime, making it difficult for patients to follow it. In the 1960s, M. leprae started to develop resistance to dapsone, the world’s only known anti-leprosy drug at that time. In the early 1960s, rifampicin and clofazimine, the other two components of recommended multidrug therapy (MDT), were discovered.

In 1981, a WHO Study Group recommended 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.

Elimination of leprosy as a public health problem

In 1991 the World Health Assembly passed a resolution to eliminate leprosy by the year 2000. Elimination of leprosy is defined as a prevalence rate of less than 1 case per 10 000 persons. The target was achieved on time and the widespread use of MDT reduced the disease burden dramatically.

  • Over the past 20 years, more than 14 million leprosy patients have been cured, about 4 million of them since 2000.
  • The prevalence rate of the disease has dropped by 90%: from 21.1 per 10 000 persons to less than 1 per 10 000 persons in 2000.
  • A dramatic decrease has been achieved in the global disease burden: from 5.2 million in 1985 to 805 000 in 1995, 753 000 at the end of 1999 and 180 618 cases at the end of 2013.
  • Leprosy has been eliminated from 119 out of the 122 countries where the disease was considered a public health problem in 1985.
  • So far, there has been no resistance to antileprosy treatment when used as MDT.
  • Efforts currently focus on eliminating leprosy at a national level in the remaining endemic countries and at a sub-national level from the others.

Actions and resources required

In order to reach all patients, leprosy treatment needs to be fully integrated into general health services. Moreover, political commitment needs to be sustained in countries where leprosy remains a public health problem. Partners in leprosy elimination also need to ensure that human and financial resources continue to be available.

The age-old stigma associated with the disease remains an obstacle to self-reporting and early treatment. The image of leprosy has to be changed at the global, national and local levels. A new environment, in which patients will not hesitate to come forward for diagnosis and treatment at any health facility, must be created.

WHO response

The WHO strategy for leprosy elimination contains the following:

  • ensuring accessible and uninterrupted MDT services available to all patients through flexible and patient-friendly drug delivery systems;
  • ensuring the sustainability of MDT services by integrating leprosy services into the general health services and building the ability of general health workers to treat leprosy;
  • encouraging self-reporting and early treatment by promoting community awareness and changing the image of leprosy;
  • monitoring the performance of MDT services and quality of patients’ care, and the progress being made towards elimination through national disease surveillance systems.

Sustained and committed efforts by the national programmes along with continued support from national and international partners have led to a decline in the global burden of leprosy. Increased empowerment of people affected by the disease, together with their greater involvement in services and the community, will bring us closer to a world without leprosy.


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