Yaws
From DrugPedia: A Wikipedia for Drug discovery
Yaws (also Pétasse tropica, thymosis, polypapilloma tropicum, pian or parangi) is a tropical infection of the skin, bones and joints caused by the spirochete bacterium Treponema pertenue. Other treponematosis diseases are bejel (Treponema endemicum), pinta (Treponema carateum), syphilis (Treponema pallidum), and Lyme Disease (Borrelia burgdorferi).
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Epidemiology
The disease is transmitted by skin contact with infected individuals or eye gnats, the spirochete entering through an existing cut or similar damage. Within ninety days (but usually less than a month) of infection a painless but distinctive 'mother yaw' ulcer appears. These tracts heal with keloid formation which can cause deformities, disabilities and limb contractures. The bone lesions caused are periostitis, osteitis, and osteomyelitis, damage to the tibia can lead to a condition known as sabre shins. In a very few cases a condition known as goundou is caused where growths on the nasal maxillae can result in extensive and severe damage to the nose and palate.
The largest group afflicted by yaws are children aged 6 to 10 years in tropical areas of the Americas, Africa, Asia or Oceania. There were World Health Organization funded campaigns against yaws from 1954 to 1963 which greatly reduced the incidence of the disease, although more recently numbers have risen again.
The disease is identified from blood tests or by a lesion sample through a darkfield examination under a microscope. Treatment is by a single dose of penicillin, erythromycin or tetracycline, recurrence or relapse is uncommon.
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; frambesia is a Modern Latin word inspired by the French word framboise ("raspberry").
Occurrence
Yaws was nearly eradicated by a worldwide treatment program in the 1950s, which reduced the number of sufferers of yaws from an estimated 50 million to nearly zero. However, the World Health Organization reported in January 2007 that yaws is on the rise again, with roughly a half a million sufferers, mostly in poor, rural areas.
Clinical Features
- Primary/ early stage – Primary sore (mother yems) appears as a large papule, about 6 cm in diameter, or as a vesicle on the knee or near the mouth. The scabs becomes macule and later a papilloma. Infective serous fluid exudes from the lesion.
- Secondary Stage – After 6-8 weeks rashes resemble a raspberrry “framboesia” develop. They fall off without pain. Periosteum and bone may be involved.
- Tertiary or later stage – It occurs after about 5 years or more and is characterized by gummatous lesion near bones and joints. Gondou, a swelling by the side of nasal bridge and gandosa ulcerative lesion on palate are two special form of the stage.
Treatment
- Benzathin penicillin G is the drug of choice in a dose of 1.2 million units for all cases and contacts, and half that dose (0.6 million units) for children under 10 years of age. In pencillin sensitive cases, erythromycin or tetracycline is used in recommended doses for a period of 15 days.
- The WHO recommended 3 modes of treatments:
- Total mass treatment: In areas where yaws is hyperendemic (>10% prevalence of clinically active yaws) treatment is given to all irrespective of disease status of person.
- Juvenile Mass Treatment: In mesoendemic communities 6% - 10% prevalence), treatment is given to all cases and to all children under 15 years of age and other obvious contacts of infectious cases.
- Selective Mass Treatment: In hypoendemic (<5% prevalence), treatment is confined to cases, their household and other obvious contacts of infectious cases.
Complications
Without treatment, about 10% of affected individuals would develop disfiguring and disabling complications after five years because the disease may cause gross destruction of the skin and bones. It can also cause deformities of the legs, nose, palate, and upper jaw.
Prevention
There is no vaccine to prevent Yaws. The principles of prevention are based on the interruption of transmission by early diagnosis and treatment of affected individuals and their contacts.
Why yaws a serious problem?
Yaws is a major public-health threat in the tropics. Tropical regions in Central and South America, Africa, Asia, and Oceania are all at continuing risk for yaws. A high percentage of children in such areas can be infected. Transmission of the disease is facilitated by overcrowding and poor hygiene, and yaws tends to be more prevalent in poor areas. In addition to making young children sick, approximately 10% of untreated children develop into young adults with deformities that are severely debilitating in the tertiary-yaws phase. For example, some patients develop destructive ulcerations of the nasopharynx, palate and nose (termed gangosa), painful skeletal deformities, especially in the legs (termed saber shins), and other soft-tissue changes (gummas, inflammatory cell infiltration).
Yaws can be completely eradicated from an area by giving penicillin or another appropriate antibiotics to everyone in the population. This may, unfortunately, cost more than a poor country can afford. From 1950-1970, a worldwide effort to eradicate yaws was begun and made progress in reducing the approximately 50 million worldwide cases; after its end, yaws has seen a resurgence. In the 1990s, attempts to eliminate yaws started again, with limited success as the effort is not worldwide or coordinated but done by individual countries. The WHO (World Health Organization) in 2007 reported about 2.5 million cases worldwide but freely admits their data is faulty, as most countries do not calculate the prevalence of yaws. WHO estimates that about 460,000 new cases of yaws occur each year.
See also
- Bacterial diseases in India
- Anthrax
- Bacterial meningitis
- Cholera
- Diphtheria
- Leprosy
- Plague
- Rickettsial diseases
- Tuberculosis
External Links
Original Source
This article was originally posted in Wikipedia.
