Eradication of yaws: historical efforts and achieving WHO's 2020 target

Abstract

Background: Yaws, one of the 17 neglected tropical diseases (NTDs), is targeted for eradication by 2020 in resolution WHA66.12 of the World Health Assembly (2013) and the WHO roadmap on NTDs (2012). The disease frequently affects children who live in poor socioeconomic conditions. Between 1952 and 1964, WHO and the United Nations Children's Fund (UNICEF) led a global eradication campaign using injectable benzathine penicillin. Recent developments using a single dose of oral azithromycin have renewed optimism that eradication can be achieved through a comprehensive large-scale treatment strategy. We review historical efforts to eradicate yaws and argue that this goal is now technically feasible using new tools and with the favorable environment for control of NTDs. We also summarize the work of WHO's Department of Control of Neglected Tropical Diseases in leading the renewed eradication initiative and call on the international community to support efforts to achieve the 2020 eradication goal. The critical factor remains access to azithromycin. Excluding medicines, the financial cost of yaws eradication could be as little as US$ 100 million.

Conclusions: The development of new tools has renewed interest in eradication of yaws; with modest support, the WHO eradication target of 2020 can be achieved.

Figure 1. Results of treatment with a single injection of benzathine penicillin in the 1950s.

Panel A shows a patient with yaws lesions (papilloma) on the face before treatment. Panel B shows the same patient two weeks after treatment with a single injection of benzathine penicillin.

Figure 2. Global distribution of endemic treponematoses in the 1950s.

The figure shows that endemic treponematoses (yaws, bejel, and pinta) were widespread between latitudes 20 North and South; yaws was the most prevalent of the three diseases.

Figure 3. Global distribution of countries actively reporting yaws cases in 2012.

The figure shows the 12 currently endemic countries, two countries that have interrupted transmission and 71 countries for which the current status is unknown. Source: Global Health Observatory: http://apps.who.int/gho/data/node.main.NTDYAWSEND?lang=en.

Figure 4. Yaws control: surveillance phase in the 1950s.

The figure shows the steps taken in the 1950s to address factors and problems that could undermine the eradication effort during the post mass treatment surveillance phase [9, page 17].

Figure 5. Impact of large-scale treatment on yaws eradication in three villages (coverage) in Nsukka, Nigeria in 1956.

The figure shows the rapid decline in the prevalence of yaws within 12 months following large-scale treatment of endemic communities and the high coverage achieved.

Figure 6. Results of treatment with a single dose of oral azithromycin in 2012.

Panels A and C show a patient with yaws lesions (papilloma) on the face and arm before treatment. Panels B and D show the same patient three weeks after treatment with a single dose of azithromycin (courtesy of Mr. Lam Duc Hien and MSF-Epicentre, Paris, France).