Neglected tropical diseases

WHO declares India free of yaws

11 May 2016 | Geneva/New Delhi −− Yaws is mainly a skin disease of childhood that affects populations living in poor socioeconomic conditions (e.g. overcrowding, poor hygiene practices, inadequate clothing) in warm, humid and tropical forest areas of Africa, Asia, Latin America and the Pacific. These populations are often isolated and live at the “end of the road” where access to health care and other social amenities is limited. The causative organism of yaws – Treponema pallidum subspecies pertenue – is genetically closely related to T. pallidum subspecies, the causative agent of syphilis.

Transmission occurs through direct (person-to-person), non-sexual contact with the fluid of an infective lesion to an uninfected person through minor injuries. Most lesions occur on the limbs. The initial lesion of yaws teems with the bacterium. The incubation period is 9–90 days (average, 21 days). About 75% of those affected are children aged under 15 years (peak incidence occurs in children aged 6–10 years). Males and females are equally affected.

Overcrowding and poor hygiene and socioeconomic conditions facilitate the spread of yaws. Without treatment, infection can lead to chronic disfigurement and disability. Diagnosis is mainly based on clinical features and confirmed by serology (rapid plasma reagin test and T. pallidum haemagglutination assay used for syphilis). Treatment with a single dose of azithromycin or a single injection with long-acting penicillin leads to a complete cure within 2–4 weeks.

In 2012 the World Health Organization (WHO) published a roadmap that set targets for the eradication, elimination and intensified control of 17 neglected tropical diseases. Dracunculiasis and yaws were targeted for eradication by 2015 and 2020 respectively. In May 2013 the Sixty-sixth World Health Assembly adopted resolution WHA66.12 on Neglected Tropical Diseases in support of the targets outlined in the roadmap. The criteria for the eradication of yaws from a public health perspective were set by a WHO Expert Committee on Venereal Infections and Treponematoses in 1960.1

The Ministry of Health and Family Welfare of India has reported interruption of indigenous transmission of yaws; the last cases were officially reported in 2003 after 7 years of intensive implementation of yaws eradication activities. On 19 September 2006, after 3 consecutive years of reporting of zero cases, the Government of India together with the WHO Regional Office for South-East Asia declared the elimination of yaws in the country. Since then, active case searches, serosurveys among children aged 1–5 years and implementation of programmatic activities have not identified any new cases or evidence of ongoing transmission.

In July 2014, the Seventh Task Force Meeting of the National Yaws Eradication Programme recommended that WHO verify and acknowledge the achievement of India in eradicating yaws. The country dossier was transmitted to WHO in December 2014. In March 2015, the Government of India, through the WHO Country Office, requested the WHO Department of Control of Neglected Tropical Diseases to send an international team of experts to verify the yaws-free status (that is, interruption of transmission) in the country.

The International Verification Team comprised three independent experts supported by seven WHO Secretariat staff (four WHO international staff and three WHO Country Office staff) and a number of experts and staff at national, State and district levels.

Ashok Moloo

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