Yaws
| Yaws | |
|---|---|
| Specialty | Infectious diseases  |
Yaws (also frambesia tropica, thymosis, polypapilloma tropicum, pian or parangi, "Bouba," "Frambösie,"[1] and "Pian"[2]) is a tropical infection of the skin, bones and joints caused by the spirochete bacterium Treponema pallidum pertenue. Other treponemal diseases are bejel (Treponema pallidum endemicum), pinta (Treponema pallidum carateum), and syphilis (Treponema pallidum pallidum).
History
Examination of ancient remains has led to the suggestion that yaws has affected hominids for the last 1.5 million years. The current name is believed to be of Carib origin, "yaya" meaning sore.[3] It is believed to have originated in tropical areas of Africa, and spread to other tropical areas of the world via immigration and slave trade.
Epidemiology
Yaws is found in humid tropical regions in South America, Africa, Asia and Oceania. Mass treatment campaigns in the 1950s reduced the worldwide prevalence from 50–150 million to fewer than 2.5 million; however during the 1970s there were outbreaks in south-east Asia and there have been continued sporadic cases in South America. It is unclear how many people worldwide are infected at present.[4]
About three quarters of people affected are children under 15 years of age, with the greatest incidence in children 6-10 years old.[5]
Presentation
The disease is transmitted by skin-to-skin contact with an infective lesion, with the bacterium entering through a pre-existing cut, bite or scratch. Within ninety days (but usually less than a month) of infection a painless but distinctive 'mother yaw' appears, which is a painless nodule which enlarges and becomes warty in appearance. Sometimes nearby 'daughter yaws' also appear simultaneously. This primary stage resolves completely within six months. The secondary stage occurs months to years later, and is characterised by widespread skin lesions of varying appearance, including 'crab yaws' on the palms and soles with desquamation. These secondary lesions frequently ulcerate (and are then highly infectious), but heal after six months or more. About ten percent of people then go on to develop tertiary disease within five to ten years (during which further secondary lesions may come and go), characterised by widespread bone, joint and soft tissue destruction, which may include extensive destruction of the bone and cartilage of the nose (rhinopharyngitis mutilans or 'gangosa').
Diagnosis
Most often the diagnosis is made clinically. Dark field microscopy of samples taken from early lesions (particularly ulcerative lesions) may show the responsible organism. Blood tests such as VDRL, Rapid Plasma Reagin (RPR) and TPHA will also be positive, but there are no current blood tests which distinguish among the four treponematoses.[3]
Treatment
Treatment is normally by a single intramuscular injection of penicillin, or by a course of penicillin, erythromycin or tetracycline tablets. A single oral dose of azithromycin was shown to be as effective as intramuscular penicillin.[6] Primary and secondary stage lesions may heal completely, but the destructive changes of tertiary yaws are largely irreversible.
Eradication efforts
The global prevalence of this disease and the other endemic trematoses, Bejel and Pinta, was reduced by the Global Control of Treponematoses (TCP) programme between 1952 and 1964 from about 50 to 150 million cases to about 2.5 million (a 95 percent reduction). Following the cessation of this program yaws surveillance and treatment became a part of primary health systems of the effected countries. However incomplete eradication led to a resurgence of yaws in 1970s with the largest number of case found in the Western Africa region.[4]
Yaws is a relatively easy disease to eradicate. Humans are likely the only reservoir of infection.[4] A single injection of long-acting penicillin or other beta lactam antibiotic cures the disease and is widely available;[7] and the disease is highly localised making case tracing relatively easy.
In April 2012 WHO decided to start a new global campaign for eradication of yaws, which has been on the WHO eradication list since 2011. According to the official roadmap the elimination should be achieved by 2020.[8] So far, this appears to have met with some success, since no cases have been seen in India since 2004.[7][9]
Certification for disease free status requires an absence of the disease for at least 5 years. In India this happened on 19 September 2011. In 1996 there were 3,571 yaws cases in India; in 1997 after a serious elimination effort began the number of cases fell to 735. By 2003 the number of cases were 46. The last clinical case in India was reported in 2003 and the last latent case in 2006.[10]
References
- ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN 1-4160-2999-0.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0. OCLC 62736861.
{{cite book}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link) - ^ a b "Yaws". MedicineNet.com. Retrieved 5 August 2012.
{{cite web}}: Unknown parameter|authors=ignored (help) - ^ a b c Capuano, Corinne; Ozaki, Masayo (2011). "Yaws in the Western Pacific Region: A Review of the Literature" (pdf). Journal of Tropical Medicine. 2011: 642832. doi:10.1155/2011/642832.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ "Yaws". WHO Fact sheet. Retrieved 2012-10-16..
- ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 22240407, please use {{cite journal}} with
|pmid= 22240407instead. - ^ a b Asiedu; Amouzou, B; Dhariwal, A; Karam, M; Lobo, D; Patnaik, S; Meheus, A; et al. (2008). "Yaws eradication: past efforts and future perspectives". Bulletin of the World Health Organisation. 86 (7): 499–500. doi:10.2471/BLT.08.055608. PMC 2647478. PMID 18670655. Retrieved 2009-04-02.
{{cite journal}}: Explicit use of et al. in:|author=(help) - ^ Maurice, John (2012). "WHO plans new yaws eradication campaign". The Lancet. 379: 1377–78. doi:10.1016/S0140-6736(12)60581-9.
- ^ WHO South-East Asia report of an intercountry workshop on Yaws eradication, 2006
- ^ Akbar, Syed (7 August 2011). "Another milestone for India: Yaws eradication". The Asian Age. Retrieved 5 August 2012.
- McNeill, William H. (1976). Plagues and Peoples. New York, NY: Bantam Doubleday Dell Publishing Group, Inc. ISBN 0-385-12122-9. OCLC 20453728.