Case of the Week - Yaws

This is a picture of a patient’s leg that is suffering from yaws. 

Yaws is a tropical infection of the skin, bones, and joints caused by the Treponema pallidum pertenue (a relative of the spirochete that causes syphilis and pinta).  Yaws can be found in the humid tropical regions of South America, Africa, Asia, and Oceania.  It was introduced to the America’s and Europe through the slave trade with Africa.  A mass treatment campaign in the 1950 eradicated it from many developed countries and greatly reduced the worldwide prevalence, however incomplete eradication led to a resurgence in the 1970’s with the largest number of cases found in Western Africa.  The majority of people affected are children under that age of 15 years of age and it is spread by skin-to skin contact with infective lesions allowing the bacterium to enter through a pre-existing cut, bite, or scratch.  Earlier in the year we had an outbreak of yaws in the school in Nalerigu and the surrounding area.

This infection, like syphilis, has three stages.  The infection starts as a painless but distinctive “mother yaw” lesion.  The infection can continue and have “daughter yaws” appear around the infection site over the course of a few months.  These lesions usually resolve by six months.  Secondary stage yaws can occur months to years later and is characterized by widespread skin lesions of different appearances.  About 10% of people will progress to tertiary yaws where bone, joint and soft tissue destruction is usually seen.  It is seen often as destruction of the bone and cartilage of the nose.

The distinctive "mother yaws" lesion

 

The treatment of the infection is a single injection of penicillin.  However, I have seen the destruction that occurs from the disease is much harder to treat and takes a much longer time to heal.  The skin lesions left behind after infection can take months to heal (some needing skin grafting) especially when the people are malnourished and live in dirty conditions. 

The disease is highly localized which makes case tracing and treatment of potentially infected individuals easy.  For example, when the outbreak occurred in the schools earlier in the year, the public health administrators went to all of the schools and gave the children shots of penicillin.  The cases of yaws we saw in clinic after that dropped dramatically.

This patient is currently admitted to our isolation ward and is undergoing dressing changes to her legs (her other leg not in the picture has similar wounds, as well as her buttocks and left elbow).  Her wounds are nice and clean and we will see if she will start to heal the wounds or if we will have to skin graft some of the bigger wounds.