Neglected tropical diseases

New trial confirms effectiveness of single-dose oral antibiotic, boosting prospects for yaws eradication

Large-scale treatment campaigns to be launched in 6 countries
Geneva | 11 April 2013

A second randomized controlled clinical trial carried out in Ghana comparing a single dose of the oral antibiotic azithromycin with the standard injection of benzathine penicillin has confirmed an earlier finding by researchers from Papua New Guinea that the medicine can effectively cure yaws.

The results of the Ghana trial were presented during the second annual Consultation on Yaws Eradication in Geneva, Switzerland on 20–22 March 2013.

“Our findings mirrored those published a year ago by researchers from Papua New Guinea” said Dr Cynthia Kwakye, principal investigator of the study in Ghana.“We even found a slightly better response to treatment with oral azithromycin compared with injected benzathine penicillin. Our study confirmed that oral azithromycin is well tolerated.”

Oral antibiotic treatment is preferable to injections and overcomes many operational and logistic constraints, making it easier for wider, rapid and large-scale interventions to treat entire populations at risk. This approach improves prospects for eradicating the disease as outlined in WHO’s roadmap on neglected tropical diseases.

“This is exciting news for the public health community as the results provide solid support for our new strategy for yaws eradication” said Dr Kingsley Asiedu, in charge of yaws eradication in the WHO Department of Control of Neglected Tropical Diseases.

Some 43 participants representing 19 countries, including 11 of the 13 countries currently known to be endemic for yaws, shared epidemiological data and discussed criteria, strategies and procedures for the verification and certification of yaws eradication.

The meeting also noted the evaluation being carried out of a new point-of-care syphilis test that can simultaneously detect both treponemal and non-treponemal infections with just a drop of blood. Traditionally, two different tests – screening and confirmation – are needed to confirm past and active infection. The same test may be useful for detecting and confirming cases of yaws.

“We have started evaluating this new test for yaws in Lihir, Papua New Guinea and so far, we are getting encouraging results” said Dr Oriol Mitja of the Lihir Medical Center. “It is a very simple test to perform and can be done in the field or in the laboratory”.

During the coming months, the WHO’s Morges strategy will be implemented in six endemic countries: Cameroon, Ghana, Indonesia, Papua New Guinea, the Solomon Islands and Vanuatu. For the other seven endemic countries, an assessment of the epidemiological situation will be carried out in preparation for mass treatment.

The results of these activities will be reviewed at the next meeting in 2014 to help refine the eradication strategy if needed.

The disease

Yaws is a chronic bacterial infection caused by Treponema pallidum subsp. Pertenue, an organism resembling that which causes venereal syphilis. The disease is found primarily in deprived communities in tropical and forested areas of Africa, Asia, Latin America and the Pacific. Poor socioeconomic conditions facilitate its spread.

Humans are the main reservoir of the infection and children are the worst affected. Yaws clinically presents as lesions of the skin, bone and cartilage. Without treatment, it can lead to gross deformities and disabilities. Yaws forms part of a group of infections caused by treponemes that include endemic syphilis (bejel) and pinta.

In November 2012, the International Task Force for Disease Eradication at its 20th meeting in Atlanta, USA, endorsed WHO’s renewed efforts to eradicate yaws.