Yaws

Abstract

IntroductionYaws, caused by Treponema pallidum ssp. pertenue, is endemic in parts of West Africa, Southeast Asia and the Pacific. The WHO has launched a campaign based on mass treatment with azithromycin, to eradicate yaws by 2020.Sources of dataWe reviewed published data, surveillance data and data presented at yaws eradication meetings.Areas of agreementAzithromycin is now the preferred agent for treating yaws. Point-of-care tests have demonstrated their value in yaws.Areas of controversyThere is limited data from 76 countries, which previously reported yaws. Different doses of azithromycin are used in community mass treatment for yaws and trachoma.Growing pointsYaws eradication appears an achievable goal. The programme will require considerable support from partners across health and development sectors.Areas timely for developing researchStudies to complete baseline mapping, integrate diagnostic tests into surveillance and assess the impact of community mass treatment with azithromycin are ongoing.

Yaws: 110 Years After Castellani's Discovery of Treponema pallidum subspecies pertenue

“…1 Yaws is currently thought to be endemic in at least 12 countries, but adequate surveillance data are lacking. 2 This disease is transmitted by contact of broken or abraded skin with the exudate of yaws lesions.…”

“…In about 10% of untreated patients, the infection progresses to the tertiary stage that is characterized by destruction of tissue, bone, and cartilage resulting in disfigurement and disability. 1 The etiological agent of yaws, T. pallidum subspecies pertenue (i.e., T. pertenue), was discovered in 1905 by Aldo Castellani, a physician and expert in neglected tropical diseases. Castellani had observed spiral-shaped bacteria in lesion material from yaws patients in Sri Lanka (formerly Ceylon), but did not ascribe significance to this observation.…”

“…From 1952 to 1964, the WHO, in concert with the United Nations Children's Fund (UNICEF), sponsored a mass treatment campaign in 46 countries. 1,2,24 About 300 million people were screened and 50 million or more cases and their contacts were treated with an intramuscular injection of long-acting penicillin. By the end of this campaign, the global burden of yaws was reduced by 95% to 2.5 million cases.…”

“…The DPP test will be used to detect yaws cases that are difficult to diagnose based on clinical symptoms because unrelated bacteria, such as Haemophilus ducreyi, can cause phenotypically similar skin lesions. 1 The DPP test may also be used for monitoring the effectiveness of azithromycin treatment.…”

“…Aside from major financial and commitment issues, several uncertainties related to the biology and epidemiology of yaws could impede this endeavor. 1,2,29 Because there is no vaccine to prevent infection, antibiotic treatment must be effective to interrupt transmission of yaws. The use of oral azithromycin as the first-line drug, while warranted based on logistics, could result in the emergence of azithromycin-resistant T. pertenue, as has been observed with T. pallidum.…”