Neglected tropical diseases

Yaws eradication: global experts meet after signature of medicine donation agreement

29 January 2018 | Geneva –– The World Health Organization (WHO) is hosting a two-day meeting to discuss the development of surveillance, monitoring and evaluation as it prepares to roll-out the first phase of a renewed global campaign to eradicate yaws.

The meeting, on 29-30 January 2018, follows the recent finalization of an agreement between WHO and the Brazilian pharmaceutical company EMS for the donation of 150 million tablets of azithromycin - an oral antibiotic. This chronic skin disease mainly affects children in poor, rural communities in WHO’s African, South-East Asia and Western Pacific regions.

“This donation will expand access to healthcare, especially in poor communities where yaws commonly occurs,” said Dr Ren Minghui, WHO Assistant Director-General for Communicable Diseases. “Tackling yaws with the support of partners also provides opportunities to address other skin diseases as we continue to support countries in strengthening their health systems towards achieving universal health coverage.”

Yaws is part of a group of bacterial infections commonly known as the endemic treponematoses.1 Poverty, low socioeconomic conditions and poor personal hygiene facilitate its spread. Without treatment, yaws can lead to chronic disfigurement and disability.

Besides the continued availability of azithromycin, access to rapid diagnostic tests and adequate funding for implementation are key requirements for successful implementation of WHO’s global yaws eradication strategy.2

At EMS, we are happy to partner with WHO to increase access to effective treatments of diseases that affect the poorest and most vulnerable populations and to leave no one behind, as part of the Sustainable Development Goals,” said Carlos Sanchez, Chairman of the Board of Directors of the NC Group, of which EMS is the main company. “We are aware of the challenges and remain committed to working with WHO in wiping out this disease as soon as possible.”

Implementation phases

Some 14 countries in three WHO regions are currently considered endemic for yaws: 8 in the African Region, 2 in the South-East Asia Region and 4 in the Western Pacific Region.

The initial focus will be on 6 countries as part of the first phase of WHO’s global yaws eradication strategy: Cameroon, Côte d’Ivoire, Ghana, Papua New Guinea, Solomon Islands and Vanuatu. An assessment is in progress in the other 8 countries to prepare them for full implementation.

Over the past five years, Ghana has collaborated with WHO in evaluating the efficacy of azithromycin and new diagnostic tests for yaws,” said Dr Anthony Nsiah-Asare, Director General, Ghana Health Service. “With our recent public health experience in defeating dracunculiasis, polio and trachoma and the near elimination of measles, we are optimistic we can interrupt transmission of yaws in the shortest possible time.

WHO is reinforcing capacities of strategic reference laboratories in affected countries as part of antimicrobial surveillance system to monitor any development of resistance to azithromycin.

Renewed thrust for global eradication

In 2012, a study conducted in Papua New Guinea demonstrated that a single dose of azithromycin given orally can effectively cure yaws. This finding provided an opportunity to accelerate the eradication of yaws by overcoming the operational and logistic constraints of standard treatment with injectable penicillin. In 2013, the World Health Assembly adopted resolution WHA66.12 on neglected tropical diseases, which targets the eradication of dracunculiasis (by 2015) and yaws (by 2020).

For more than five years and through collaborative research in a number of countries, we have accumulated enough experience to guide the effective use of donated azithromycin,” said Dr Oriol Mitjà, who led the study as well as the pilot implementation of WHO’s eradication strategy in Papua New Guinea.

Past eradication efforts

Yaws and other endemic treponematoses were almost eradicated in the mid-1960s after WHO and UNICEF (the United Nations Children’s Fund) jointly led a worldwide campaign in 46 countries between 1952 and 1964.

During this period, more than 300 million people were examined and about 50 million were treated with injectable penicillin.3 By 1964, the prevalence of the diseases had been reduced by almost 95%, making this joint WHO–UNICEF campaign one of the most remarkable success stories in public health.

However, premature integration of activities on yaws and other endemic treponematoses into weak primary health-care systems, and the dismantling of the vertical eradication programmes after 1964, led to the failure to finish with the remaining 5% of cases. By the late 1970s, the diseases had resurged in a number of countries, particularly in West Africa, prompting the adoption by the World Health Assembly of resolution WHA31.58 on the control of endemic treponematoses in 1978.

Yaws is a chronic bacterial infection caused by infection with Treponema pallidum subsp. Pertenue, an organism which resembles the one that causes venereal syphilis.

Infection is transmitted from person to person. Children bear the brunt of the disease. Yaws clinically presents as lesions of the skin, bone and cartilage. Without treatment, gross deformities and disabilities can result.

The recently (2017) developed WHO strategy on skin-NTDs4 is expected to contribute to strengthening integrated surveillance in countries where yaws and other skin-related neglected tropical diseases are endemic. Collaboration with other programmes will be critical in identifying endemic foci of yaws and reducing the cost of yaws eradication.

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1The endemic treponematoses are caused by spiral bacteria of the genus Treponema. They also include endemic syphilis (bejel) and pinta. Yaws is the most common of these three infections.
2Eradication of yaws – the Morges Strategy. Wkly Epidemiol Rec. 2012;87:189–200 (http://www.who.int/wer/2012/wer8720.pdf).
3India used injectable penicillin to carry out a nationwide campaign from 1996 to 2003. It declared interruption of yaws transmission in 2006. WHO verified India free of yaws in 2016.
4Mitjà O, Marks M, Bertran L, Kollie K, Argaw D, Fahal AH et al. Integrated control and management of neglected tropical skin diseases. PLoS Negl Trop Dis. 2017;11: e0005136. doi:10.1371/journal.pntd.0005136.


Contact:
Ashok Moloo
WHO/HTM/NTD
Telephone: +41 22 791 16 37
Mobile phone: +41 79 540 50 86
molooa@who.int
@ntdworld

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