About Leprosy (Hansen’s Disease)

What is Leprosy?


Leprosy or Hansen’s disease is a chronic infectious disease caused by the bacillus Mycobacterium leprae. It mainly affects the skin, peripheral nerves, upper respiratory tract and the eyes. Symptoms usually appear three to five years after infection, manifesting as skin patches and nerve damage, but can take up to 20 to 30 years in some cases. The disease is thought to spread through close and frequent contact with someone who is infected via droplets from the nose and mouth. However, leprosy is not highly contagious—the infectivity of M.leprae is extremely low. Most people will not develop the disease even if they are exposed to infection because their immune systems are strong enough to cope.

Initial Symptoms

A common early symptom of leprosy are skin lesions. These discolored patches can appear anywhere on the body and can be white or reddish-brown, flat or raised. They have impaired sensitivity to pain, temperature or touch, which is a criterion used by grassroots health workers to diagnose a case of leprosy.


The treatment for leprosy recommended by the WHO is multidrug therapy (MDT), a combination of three drugs: rifampicin, clofazimine and dapsone. MDT comes in blister packs containing a one-month (28-day) supply, with the days of the month and dosages printed on the back to make it easier for patients to comply with their treatment..


With the consent of the person diagnosed with leprosy, the WHO recommends administering of a dose of rifampicin to family members and other close contacts of the patient, who have a higher risk of developing the disease, as a preventive measure.

Residual Disability

If treatment is delayed or if a reaction* occurs during or after treatment and is not properly treated, this can cause peripheral nerve damage, sensory paralysis and loss of muscle strength, leading to physical disability. In order to prevent permanent disability, it is therefore important to detect leprosy at an early stage and to recognize and appropriately treat reactions that occur after the start of treatment.
*A lepra reaction occurs when the body’s immune system reacts to M.leprae bacteria.

Progress of Leprosy Elimination

Setting of an Elimination Target

In May 1991, the 44th World Health Assembly unanimously adopted the goal of eliminating leprosy as a public health problem by the year 2000, with “elimination” defined as a disease prevalence rate of less than 1 case per 10,000 population. With the setting of a clear target, governments of leprosy-endemic countries made leprosy control a health priority and invested the necessary budgetary and human resources. NGOs also strengthened their collaboration with governments and the WHO around this common goal, and early detection and treatment were promoted.

Free Distribution of Drugs

Further impetus for leprosy elimination came with the distribution of multidrug therapy free of charge worldwide. Sasakawa Health Foundation supported research and development of MDT, provided technical and financial support for trials in endemic countries, and subsequently promoted the widespread use of MDT around the world. In July 1994, at the first international conference on the elimination of leprosy as a public health problem held in Hanoi, Vietnam, Yohei Sasakawa, then president of The Nippon Foundation, announced that the foundation would donate a total of US$50 million (US$10 million per year) between 1995 and 1999 to fund the free distribution of MDT throughout the world. From 2000, the pharmaceutical company Novartis took over the free provision of MDT. In 1985, there were more than 5 million registered leprosy patients worldwide. By the end of 2000, the elimination target and the free provision of MDT had helped to reduce this number to around 600,000*.

*Note: This figure represents the number of registered patients at the start of 2001.

Toward Zero Leprosy

Although leprosy has been eliminated as a public health problem in most countries, around 200,000 new cases are still reported each year. The WHO has now adopted the slogan “Zero Leprosy,” which was developed by a private-sector partnership to promote further progress against the disease in the wake of the elimination strategy.

In 2021, the WHO launched Towards zero leprosy: Global Leprosy (Hansen’s disease) Strategy 2021-2030. The long-term vision of Zero Leprosy is Zero Infection, Zero Disease, Zero Disability and Zero Discrimination. The strategy sets a number of indicators to be achieved by 2030 with the goal of leprosy elimination, defined as the interruption of transmission. These are:

・120 countries with zero new autochthonous cases of leprosy
・70% reduction in annual number of new cases detected
・90% reduction in rate per million population of new cases with grade-2 (visible) disability
・90% reduction in rate per million children of new child cases with leprosy

Note: The above indicators are based on 2020 baseline figures. In addition, the strategy is structured around four pillars: 1) Implement zero leprosy road maps in all endemic countries; 2) Scale up leprosy prevention alongside integrated active case detection; 3) Manage leprosy and its complications and prevent new disability; and 4) Combat stigma and ensure human rights are respected.

Leprosy and Human Rights

In 2003, WHO Goodwill Ambassador for Leprosy Elimination and then president of The Nippon Foundation, Yohei Sasakawa, began to address the issue of discrimination in leprosy by approaching the Office of the United Nations High Commissioner for Human Rights. Although leprosy had become a curable disease, the persistent stigma against persons affected by leprosy and their family members denied them opportunities in education, marriage, employment, and excluded them from society. An important moment came in August 2005 when persons affected by leprosy addressed a session of the UN Sub-Commission on the Promotion and Protection of Human Rights for the first time. However, the following year, when the UN Commission on Human Rights was abolished and replaced by the UN Human Rights Council, the Sub-Commission was also disbanded and its members who had developed an understanding of leprosy went their separate ways.

Noting that the mandate of national government representatives was strengthened under the new UN Human Rights Council, Sasakawa approached the Ministry of Foreign Affairs of Japan. In 2007, the Japanese government took the decision that one of the pillars of its diplomacy would be to appeal to the international community for an end to discrimination related to leprosy. Sasakawa, who was at the heart of these efforts, was appointed the Japanese Government Goodwill Ambassador for the Human Rights of Persons Affected by Leprosy, and remained actively involved.

With the cooperation of Japan’s Ministry of Foreign Affairs, Sasakawa’s ongoing advocacy contributed to a resolution on Elimination of discrimination against persons affected by leprosy and their family members, accompanied by Principles and Guidelines, adopted unanimously by the 192 members of the UN General Assembly at that time in December 2010. Following this, The Nippon Foundation worked to encourage the implementation of the Principles and Guidelines in each country, holding five symposiums on leprosy and human rights in different parts of the world between 2012 and 2015. As a result, in November 2017, a UN Special Rapporteur on leprosy was appointed to follow up and report on progress made and measures taken by states in the implementation of the Principles and Guidelines in each country.

Japanese Initiative in the Efforts to Eliminate Discrimination against Persons Affected by Leprosy and Their Family Members (Ministry of Foreign Affairs of Japan)

Growth and Influence of People’s Organizations

In the days when leprosy could only be treated in certain hospitals or sanatoriums, and as a result of segregation policies, patients ended up living in these institutions or forming communities nearby, unable to return home because of the stigma associated with the disease.

Treating leprosy as a disease separate from other diseases helped to shape society’s perception of leprosy. Attitudes were also influenced by religious beliefs, superstition and fear.

But over time, those who had been institutionalized or whose experience of leprosy continued to define their lives began to find a voice. They chose to speak up for themselves rather than allow others to define who they were and how they should live.

Examples include the Sungai Buloh Settlement Council (Malaysia, founded in 1946), the All-Japan Hansen’s Disease Sanatoria Residents Association (Japan, 1951), and the Movement for the Reintegration of Persons Affected by Hansen’s Disease (MORHAN) (Brazil, 1981).   

With the creation of the International Association for Integration, Dignity and Economic Advancement (IDEA) in 1994, this trend spread around the world. It has led to initiatives to lift people out of poverty, create education and employment opportunities, facilitate access to social services and disability care, and restore dignity.

In response to actions taken and led by persons affected by leprosy and their organizations, there is now widespread recognition that their participation in efforts to address the remaining challenges of leprosy is essential.

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