Yaws - epidemiology, prevention and control

YAWS – EPIDEMIOLOGY, PREVENTION AND CONTROL

Dr. Priya AroraAssoc. Prof

Deptt. Of Community MedicineACMS

• Chronic, Contagious, highly infectious, Non-venereal disease caused by Spirochaete Treponema pallidum.

• Usually begins in early childhood.• Primary skin lesion followed by generalised

eruption and a late stage of destructive and disfiguring and debilitating lesions of skin and bone.

• Chronic disease showing relapses over several years.

GEOGRAPHIC DISTRIBUTION

• Exclusively confined to the belt between the Tropic of Cancer and Capricorn.

• Significant public health problem in Africa, South-east Asia and Central America in the past

• Resurgence in certain areas of Africa• Persistent low level in India till a decade ago.

INDIA• Reported from tribal communities living in

hilly forests and difficult to reach areas in 49 districts of 10 states.

• States affected – Andhra Pradesh, Assam, Chhattisgarh, Gujrat, Jharkhand, Madhya Pradesh, Maharashtra, Orissa, Tamil Nadu, U.P.

• Number of cases brought down from 3500 in 1996 to zero in 2004.

• Certfication of disease free status in 2011

AGENT• Treponema pertenue• Resembles T. pallidum culturally and

morphologically• Occurs in the epidermis of lesions, lymph glands,

spleen and bone marrow.Reservoir-Man is the only known reservoirMost latent cases found in cluster around an

infectious caseSource of infection-Skin lesions and exudates from early lesions

HOST FACTORS

AGE-Primarily a disease of childhood and

adolescence.GENDER -M > FIMMUNITY –No natural immunity.

ENVIRONMENTAL FACTORS

CLIMATE –Endemic in warm and humid climate.SOCIAL FACTORS –More common in tribal people Poor personal hygiene, overcrowding, low std. of

living predisposing factors

MODE OF TRANSMISSION

DIRECT CONTACTFOMITESVECTORS

INCUBATION PERIOD –9 – 90 DAYS

CLINICAL FEATURES• EARLY YAWS- - Primary lesion (Mother Yaws) appears at the site of

inoculation after 3-5 weeks. - Seen on exposed parts of body - Lymph glands are enlarged. - With in next 3-6 weeks generalised eruption appears

consists of large yellow, crusted, granulomatous eruptions .

-During next five years, mucous membrane, periosteal snd bone lesions develop, subside and relapse.

- The early lesions are highly infectioous

• LATE YAWS - Destructive and deforming lesions of skin,

bone and periosteum develop. CRAB Yaws – lesions of palm and soles Gangosa – lesions of soft palate, hard palate

and nose

CONTROL OF YAWS

1. SURVEY-Clinical survey of all families in endemic area.Should not cover less than 95% of total population.2. TREATMENTSingle dose of Azithromycin or single long acting

Penicillin will cure infectionSimultaneous treatment of cases and their likely

contacts in the community will interrupt transmission

• WHO has recommended 3 treatment policies-TOTAL MASS TREATMENT- In hyperendemic

areas(> 10% prevalence of clinically active Yaws). Entire population treated with Pen G.JUVENILE MASS TREATMENT – In mesoendemic

areas(5-10% prevalence). Treatment given to cases, contacts and all

children below 15 yearsSELECTIVE MASS TREATMENT – In hypoendemic

areas(<5% prevalence) Treatment to cases, household and other obvious

contacts

3. RESURVEY AND TREATMENT-Resuveys every6-12 months to assess problem

magnitude.4. SURVEILLANCE-Surveillance and Containment measures for

affected villages, households and contacts of known Yaws cases.

Epidemiological investigations to trace possible sources of infection, prophylactic treatment of contacts, follw up of cases

5. ENVIRONMENT IMPROVEMENT

6. ERADICATION EFFORTS-TOTAL COMMUNITY TREATMENTTOTAL TARGETTED TREATMENT

• YAWS ERADICATION PROGRAMME • The programme was started in 1996-97 in Koraput districts of Orissa then extended to endemic states as a centrally sponsored health scheme with the objectives of:

1. Interrupting the transmission of yaws infection (no case) in the country

2. Eradication of Yaws (i.e. no sero reactivity to RPR/VDRL in children below 5 years of age) from the country.