Leprosy

Leprosy situation in the African Region is currently characterized by a slow but steady decline of detection and prevalence rates. Indeed, between 2013 and 2022, Leprosy prevalence rate declined from 24.4 to 21.3 cases per million, with detection rates also decreasing from 22.5 to 18.5 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 our region, have reported no new cases among children for over five years, positioning them on the brink of achieving the interruption of transmission. In spite these achievements there is a need of maintaining high level political commitment as well as encouraging donor support for essential activities such as integrated capacity building, integrated active case finding, MDT supply and logistics to achieve interruption of leprosy transmission by 2030 according to the new NTDs road maps targets.

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.

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.

The 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.

Leprosy 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.

After 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 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.

Supporting countries endemic for leprosy

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

Monitoring the leprosy situation

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

Multiple 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

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.

• Sasakawa Health Foundation
• Novartis − Corporate responsibility
• The International Federation of Anti-Leprosy Associations (ILEP)
• International Leprosy Association (ILA)
• Leprosy Research Initiative
• UN Special Rapporteur on the elimination of discrimination against persons affected by leprosy and their family members

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:

• • Interruption of transmission and elimination of leprosy disease (2023)
  • Towards zero leprosy: global leprosy (Hansen’s disease) strategy 2021–2030 (2021)
  • Leprosy/Hansen disease: contact tracing and post-exposure prophylaxis: technical guidance (2020).
  • Leprosy Hansen disease: management of reactions and prevention of disabilities: technical guidance (2020).
  • Guidelines for the diagnosis, treatment and prevention of leprosy (2018)
  • A guide for surveillance of antimicrobial resistance in leprosy: 2017 update

Promoting the integrated approach to skin-related neglected tropical diseases

Skin 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.

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.

WHO 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