1. OMS em África
  2. Leprosy

Leprosy

Leprosy

    Overview

    Leprosy is a chronic infectious disease that is caused by a type of bacteria called Mycobacterium leprae (M. leprae). It commonly causes severe nerve damage and disfiguring pale-coloured skin sores on the arms and legs. Nerve damage can affect the eyes, lead to muscle weakness and a loss of feeling in the arms and legs.

    You can only acquire leprosy if you come in close contact with someone with untreated leprosy and children are at the greatest risk. Leprosy often develops after many years and possibly even decades of the initial exposure to the leprosy-causing bacteria.

    Treatment is specific to the type of leprosy and severity of the condition. Tuberculoid leprosy is a mild, less severe and less contagious form of leprosy. Lepromatous leprosy is more severe and is characterised by widespread skin bumps, rashes, numbness and weak muscles.

    In the African Region, leprosy prevalence rates have dropped from 57 516 cases in 2000 to 33 690 in 2010, this represents a 42% decrease. A leprosy-induced irreversible disability currently affects about one million people in the Region. The most vulnerable and high-risk populations are living in poor rural areas in the Democratic Republic of the Congo, Ethiopia, Madagascar, Mozambique, Nigeria and Tanzania.

    WHO and global response

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    Supporting countries endemic for leprosy

    WHO provides technical support to Member States through conduct of situational assessments and programmatic reviews, capacity‐building and advocacy.

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    Monitoring the leprosy situation

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    Every year, WHO collates epidemiological data on leprosy from all its Member States and publishes a consolidated report in the Weekly Epidemiological Record. The data including key indicators provided by countries are published in the  Global Health Observatory (GHO).

    The WHO closely monitors countries' efforts to sustain leprosy elimination as public health problem as well as progress towards interruption of transmission and elimination leprosy disease.

     

    Facilitating the provision of medicines for leprosy

    lMultiple Drug Therapy (MDT), a combination of three medicines (dapsone, clofazimine and rifampicin) has been the cornerstone of leprosy treatment since the 1980s.

    WHO has facilitated the provision of MDT medicines worldwide and free-of-charge through a donation financed by The Nippon Foundation (from 1995 to 1999) and since year 2000 onwards by Novartis.

    Annual Request for the supply of free anti-leprosy medicines

     

    Promoting advocacy and partner coordination for leprosy elimination

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    For many years, leprosy elimination interventions in countries as well as at the international level have benefitted from dedicated and engaged partners such as the International Federation of Anti-Leprosy Associations (ILEP) and its members; the International Leprosy Association (ILA); The Nippon Foundation (TNF) and Sasakawa Health Foundation (SHF); Novartis; the Leprosy Research Initiative (LRI); and organizations representing persons who have experienced or are affected by leprosy.

    WHO has been critical in mobilizing various partners, in countries as well as internationally, to capitalize on their strengths and comparative advantage.

    Since May 2001, WHO has also counted on Mr Yohei Sasakawa, the WHO Goodwill Ambassador for Leprosy Elimination and Chairman of The Nippon Foundation, who has travelled around the world to advocate for the leprosy elimination. He has met many heads of states and governments, cabinet ministers, Director-generals, and hospital chiefs to advocate for the elimination of leprosy. During his extensive travels to countries, he has visited villages and remote areas to meet patients and their families and to spread the simple message that leprosy is curable and treatable and that there should be no stigma and discrimination against persons affected by leprosy and their families.

     

    Publishing state-of-the art guidance to reduce the leprosy burden

    WHO publishes guides and tools to support translation of WHO recommendations into practice. These resources are intended for use by national programmes and partners to support planning, implementing, monitoring and evaluating activities to further reduce the leprosy burden.

    In recent years, WHO has published the following guidance documents:

     

    Promoting the integrated approach to skin-related neglected tropical diseases

    lSkin diseases are the third most prevalent cause of illness and one of the top 10 causes of disability. They are also among the 10 most common causes of outpatient visits.

    Of the 20 neglected tropical diseases (NTDs), more than half present with skin manifestations (the so‐called skin NTDs) and are often associated with long-term disability, stigmatization and mental health problems. The skin NTDs include Buruli ulcer, cutaneous leishmaniasis, post-kala azar dermal leishmaniasis, leprosy, lymphatic filariasis (lymphoedema and hydrocele), mycetoma, onchocerciasis, scabies, yaws, and fungal diseases. They all require similar detection and case-management approaches that present opportunities for integration, which both increases cost–effectiveness and expands coverage.

    The major areas in which integrated approaches can be developed include community awareness, epidemiological surveillance and disease mapping, training for health workers and community health workers, active case finding and programme monitoring and evaluation.

    In areas of treatment, common approaches such as wound and lymphoedema management, prevention of disability, surgery and rehabilitation can be implemented using the same health infrastructure and health workers. Most nongovernmental organizations and health professional organizations are involved in multiple skin NTDs.

    WHO has recently published a Strategic framework for integrated control and management of skin-related neglected tropical diseases

    To ensure efficiency, sustainability and scale, WHO recommends that Leprosy intervention should be integrated within skin NTDs approach adapted to the diseases present in a particular country.

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    In the African Region, several countries, including but not limited to Angola, Benin, Cameroon, Congo, Côte d’Ivoire, the Democratic Republic of the Congo, South Sudan, and Togo are implementing integrated approach.

    lWHO has developed online courses and a Skin App for Android and iOS to assist health workers in the field in the diagnosis of skin NTDs including Leprosy

     

     

     

     

     

    Key Facts

    • Leprosy, also known as Hansen’s disease, is a devastating chronic infectious disease caused by Mycobacterium leprae and Mycobacterium lepromatus.
    • The disease predominantly affects the skin and peripheral nerves. 
    • Left untreated, the disease may cause progressive and permanent disabilities.
    • The bacteria are transmitted via droplets from the nose and mouth during close, prolonged and frequent contacts with untreated cases.
    • Leprosy is curable with Multiple Drug Therapy (MDT).
    • In 2023, a total of 182,815 new cases of Leprosy were reported across all six WHO regions. Of these, 21,043 new cases (11.5%) were reported in the African region.
    • People affected by leprosy are often subject to discrimination and stigmatization

    Scope of the problem

    Leprosy Elimination as a public health problem (defined as end-of-year prevalence rate less than 1 per 10 000 population as per World Health Assembly resolution 44.9 and AFR/RC44/R5), had been achieved and was sustained until 2023 at the regional level and in almost all the Member States of the African Region. However, the leprosy burden and pockets of hotspots remain in many countries with more than 20,000 new cases reported every year in our Region.

    During 2023, there were 182 815 new cases reported globally with 21 043 (11.5%) new cases from 45 out 47 countries in African Region corresponding to a rate of detection of 17.2 per million population.

    The geographical distribution of new Leprosy cases in 2023 in the Africa region is as follows:

    • Four countries reported 0 cases: Algeria, Lesotho, Eswatini, Seychelles.
    • Nine countries reported 1 to 10 new cases: Botswana, Cape Verde, Eritrea, Gabon, Gambia, Guinea-Bissau, Equatorial Guinea, São Tomé and Príncipe, Zimbabwe.
    • Ten countries reported 11 to 100 new cases: Benin, Cameroon, Kenya, Liberia, Mali, Mauritania, Namibia, Rwanda, Togo, South Africa.
    • Sixteen countries reported 101 to 1000 new cases.
    • Six countries reported more than 1000 new cases: Democratic Republic of the Congo, Ethiopia, Madagascar, Mozambique, Nigeria, Tanzania.
    • 2 countries did not report any cases: Mauritius and Zambia.

    The occurrence of new leprosy cases among children serves as a proxy indicator for recent transmission. In 2023, a total of 1,633 new child cases (7.8% of all new cases) were reported in the African Region, corresponding to a rate of 2.6 per million child population. New cases with Grade 2 Disability (G2D) indicate delayed case detection. In the African region, 3,026 new cases with G2D were detected, corresponding to a rate of 2.5 per million population, accounting for 14.4% of all new cases detected during the year. This increase could be linked to the resumption of activities following the COVID-19 pandemic, as well as a decrease in expertise at the country level.

    More detailed information on key leprosy indicators is available on The Global Health Observatory.
     

    Progress in the last 10 years

    The leprosy situation in the African Region is currently characterized by a slow but steady decline in both detection and prevalence rates. Between 2013 and 2023, the leprosy prevalence rate decreased from 24.4 to 20.4 cases per million, while the detection rate also declined from 22.5 to 17.2 cases per million. Leprosy elimination as a public health problem has been achieved and sustained in almost all countries of the region. Notably, eight out of the 47 countries (17%) in the region have reported no new cases among children for over five years, positioning them close to achieving the interruption of transmission.

    Despite these achievements, there remains a need to maintain high-level political commitment and secure continued donor support for essential activities, such as integrated capacity building, active case finding, and the supply and logistics of Multi-Drug Therapy (MDT). These efforts are crucial to achieving the interruption of leprosy transmission by 2030, in line with the new NTDs roadmap targets.
     

    Clinical and epidemiological characteristics of cases

    Causative organism

    Leprosy is caused by Mycobacterium leprae and Mycobacterium lepromatus, an acid-fast bacterium affecting mainly the skin and nerves.

    Transmission

    The disease is transmitted through droplets from the nose and mouth. Prolonged, close contact over months with someone with untreated leprosy is needed to catch the disease. The disease is not spread through casual contact with a person who has leprosy like shaking hands or hugging, sharing meals or sitting next to each other. Moreover, the patient stops transmitting the disease when they begin treatment.

    Signs and symptoms

    Diagnosis

    The diagnosis of leprosy is done clinically. Laboratory-based services may be required in cases that are difficult to diagnose or to monitor drug resistance. 

    TransmissionThe disease manifests commonly through skin lesion and peripheral nerve involvement. Leprosy is diagnosed by finding at least one of the following cardinal signs: (1) definite loss of sensation in a pale (hypopigmented) or reddish skin patch; (2) thickened or enlarged peripheral nerve, with loss of sensation and/or weakness of the muscles supplied by that nerve; (3) microscopic detection of bacilli in a slit-skin smear.

    Based on the above, the cases are classified into two types for treatment purposes: Paucibacillary (PB) case and Multibacillary (MB) case.

    PB case: a case of leprosy with 1 to 5 skin lesions, without demonstrated presence of bacilli in a skin smear.

    MB case: a case of leprosy with more than five skin lesions; or with nerve involvement (pure neuritis, or any number of skin lesions and neuritis); or with the demonstrated presence of bacilli in a slit-skin smear, irrespective of the number of skin lesions.
     

    Treatment

    TreatmentLeprosy is a curable disease. Early diagnosis and complete treatment with Multiple Drug Therapy (MDT) remain the key strategies for reducing the disease burden of leprosy and help to prevent disabilities.

    The 2018 Guidelines for the diagnosis, treatment and prevention of leprosy  published by WHO, recommends the same 3-drug regimen with rifampicin, dapsone and clofazimine for all leprosy patients, with a duration of treatment of 6 months for PB leprosy and of 12 months for MB leprosy.

    The treatment also includes presentation of disabilities as well as management of reactions and complications.

    Prevention

    Early case detection and prompt treatment with MDT, despite having the capacity to reduce leprosy burden, have proven insufficient to interrupt transmission, excepted in very low endemic countries.

    The technical guidance for contact tracing and post-exposure prophylaxis published by WHO recommends tracing household contacts along with neighbourhood and social contacts of each patient, accompanied by the administration of a single dose of rifampicin as preventive chemotherapy. This strategy has been implemented in some countries of the African Region such as Benin, Comoros, Nigeria, and Tanzania, and would show impact after a five-year period.

    Strategy

    StratAfter detailed consultations with countries, experts, partners and persons affected by leprosy, WHO released the Towards zero leprosy: global leprosy (Hansen’s disease) strategy 2021–2030 aligned to the neglected tropical diseases road map 2021–2030. The Strategy calls for a vision of zero leprosy: zero infection and disease, zero disability, zero stigma and discrimination and the elimination of leprosy (defined as interruption of transmission) as its goal. The four strategic pillars of the strategy include:

    1. implementing integrated, country-owned zero leprosy roadmaps in all endemic countries
    2. scaling up leprosy prevention alongside integrated active case detection
    3. managing leprosy and its complications and prevent new disability
    4. and combatting stigma and ensuring human rights are respected.

    The Strategy also recognizes that global and national investment in research is essential to achieving zero leprosy and includes a set of key research priorities.

    Research priorities

    lResearchresearch priorities include:

    • More effective approaches to active case detection in different contexts and levels of endemicity
    • Innovative approaches to building capacity of health workers
    • Tools for geospatial distribution of leprosy and surveillance mapping
    • Improved preventive approaches including chemotherapy regimen and vaccines
    • Tools for epidemiological and programme monitoring
    • Diagnostic tests, including at community and point-of-care level, for disease and infection
    • Impact of case finding and contact tracing strategies on the number of new cases with disabilities
    • Optimized and new treatment options for reactions and nerve function impairment
    •  Diagnostic tools for detection and monitoring of nerve function impairment and reactions
    • Improved understanding of the mechanism of leprosy reactions
    • More effective drugs or drug combinations, or shorter regimens, to treat or prevent leprosy
    • Improved understanding of transmission including host, agent and environmental factors and zoonotic transmission
    • Effective models of care throughout the patient journey
    • Digital health applications in leprosy
    • Inclusive approaches in community-based rehabilitation and stigma reduction
    • New technologies for wound care, orthosis, prosthesis and materials for footwear.
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