Yaws all set for eradication - third disease to be eradicated in independent India

Syed Akbar
Hyderabad: India is all set to eradicate yet another disease. Come September 19 and the country completes the mandatory five-year waiting term for yaws, a skin disease that mostly affects tribal populations, to be declared as eradicated. If everything goes on well, yaws will be the third disease to be eradicated 
in independent India.
Earlier, India has successfully eradicated two major health problems, smallpox and guinea 
worm disease (dracunculiasis). Yaws will be the third in the series of disease eradication in the 
country. This successful experience has now encouraged health authorities to list another disease - lymphatic filariasis -  for elimination by 2015, five years before the deadline of 2020 set by the World Health Organisation.

For a disease to be certified by the WHO as "eradicated", a country needs first to 
"eliminate" the disease. Yaws was declared eliminated on September 19, 2006 after there was not even a single clinical case  for three years since 2003. After a disease is eliminated in a particular country, there should not be any clinical  or latent cases for full five years to be eligible for disease eradication certificate by the WHO.

In the case of yaws there have been no cases in any part of the country since 2003. And 
after September 19, 2006 there were no cases of even latent yaws. The mandatory five year term concludes on  September 18. If by then there are no fresh cases, India will be eligible to approach the WHO for yaws eradication certificate.

"A disease is said to be eliminated if the number of cases go down to one or below per 1000 population. And if the number of cases is zero and there are no fresh cases for the next five years, the disease 
is said to be eradicated. Yaws is now qualified for WHO eradication certificate. But there may be some delay as health authorities from districts where the disease was once prevalent are yet to submit their "nil reportage". In Andhra Pradesh yaws was prevalent in Srikakulam, Vizianagaram, East and West Godavari, Khammam and Warangal districts. We are waiting for reports from districts and in fact we sent reminders to them earlier this week," said Dr AK Mukhopadhyay, incharge of Rajahmundry unit of the National Centre for Disease Control (NCDC).

NCDC authorities are now busy conducting "sero surveillance" in these districts in Andhra 
Pradesh and other States, where yaws was once a major health nuisance, to rule out even latent cases of yaws. As part of the exercise blood samples of all children below five years are tested covering both tribal and non-tribal villages. "So far we did not encounter even a single case. We are keeping a watch on migrant populations too to rule out fresh cases if any," Dr Mukhopadhyay said.

It took nearly 15 years for India to win the war against yaws. Though it has been fighting against yaws for more than four decades, it was only in mid 1990s that concerted efforts began to first eliminate 
and then eradicate the disease. That India was sincere is evident from the following statistics. There were as many as 3571 yaws cases in 1996 and within a year the number of cases came down five times i.e 735 in 1997. By 2003 the  number of cases fell to just 46 and since then not a single case has been reported.

India selected yaws for eradication as there are several favourable factors like man is 
the only reservoir of infection, availability of a "magic bullet" (single injection of long-acting penicillin) and high  localisation of the disease.

Even after elimination of yaws, health authorities have been actively looking as latent 
cases which do not have clinical manifestation i.e person is infected by yaws but the symptoms do not appear. According to an NCDC report, there are 5 to 10 times more latent cases than clinical cases of yaws. Though there are no visible lesions during the latent stage, infectious relapses may occur which can cause new outbreaks.

"After an initial control effort, we are resurveying communities frequently to detect remaining cases. Serological surveillance will establish that transmission of infection has been stopped," Dr Mukhopadhyay pointed out.

Lymphatic filariasis is prevalent in remote tribal dominated villages of West and East Godavari district and it's going to be the next disease targeted for elimination in the next four years. Lymphatic filariasis in observed in weavers' community too of these districts.
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Fact file
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* Yaws is a non-venereal skin disease that mostly afflicts tribal populations inhabiting hilly regions and inaccessible areas. Yaws has a history of just a little over 150 years in India as it was first noticed in tea workers in Assam in the later part of the 19th century.

* The disease was neglected for long as the victims were mostly tribals and limited to a few districts in a few States. The Yaws Eradication Programme (YEP) took momentum after the WHO took it up for worldwide eradication. India has successfully eliminated yaws in 2006 and is now qualified for WHO disease eradication certificate. If this happens, yaws will be the third disease to be eradicated in the last 60 years.

* According to National Centre for Disease Control, yaws was responsible not only for 
great deal of misery to the affected people but also contributed significantly to the economic strain of the already  impoverished segments of society.

* Yaws belongs to a group of chronic bacterial infections and is characterised by a 
primary skin lesion, which usually occurs in children and adolescents in endemic situation. These lesions may persist for 3-6 months and heal spontaneously, often leaving a scar. Nocturnal bone pain and tenderness of the tibia and other long bones are common, points out an NCDC report. Usually after 5 years of onset of illness, destructive  lesions of the skin, bone and cartilage may appear which are non-infectious but may make a person disabled.

* Yaws is caused by Treponema pallidum subspecies pertenue. The disease is transmitted by 
person-to-person contact. The lesions caused by yaws look like those of skin tuberculosis, leprosy and 
psoriasis.