Flesh-eating disease causes havoc

Ghana reports 11 000 casese

THE World Health Organisation has said a tropical flesh-eating disease known as Buruli ulcer is spreading across parts of West Africa, leaving at least 40 000 people with bloody infected wounds and swollen skin ulcers.

Buruli ulcer is a devastating skin disease caused by mycobacterium ulcerans, a pathogen belonging to the same family of organisms that causes tuberculosis and leprosy. Unlike these conditions, however, Buruli ulcer is a poorly understood tropical disease that has emerged dramatically since the 1980s.

The causative agent has unique features and its exact mode of transmission remains unknown.

However, some patients state that the lesions develop at the site of antecedent trauma. Research suggests that in Africa, some aquatic insects of the order Hemiptera can harbour mycobecterium ulcerans in their salivary glands and transmit the disease to experimental animals.

More recent data from Australia suggests that salt marsh mosquitoes test positive for mycobacterium ulcerans DNA, although transmission by this type of mosquito has not been established.

There are no confirmed reports of Buruli ulcer in Zimbabwe. But, closer to home, three cases of Buruli ulcer were described among patients in Malawi’s three villages — namely, Nkhata Bay, Ntchen and Thyolo.

Further reports from Malawi suggested there were more unconfirmed cases in the country.

The disease has been reported in 30 countries in the world, mainly in poor rural communities that live close to water. According to World Health (WHO) 2006 statistics, Ivory Coast reported 24 000 cases, Ghana 11 000 and Benin 7 000 cases.

An increasing number of cases is being reported in Cameroon, Congo, Gabon, Sudan, Togo and Uganda.

In some African countries Buruli has become the second most prevalent mycobacterial disease after tuberculosis.

Rapid diagnostic tests are lacking, surveillance and reporting are poor and antibiotics have little effect.

Treatment relies on surgery, often-involving extensive excision and skin grafting.

To save lives, limbs have to be amputated in severe cases.

Buruli ulcer often starts as a painless, mobile swelling in the skin called a nodule. The disease can present as a large area of induration or a diffuse swelling of the legs and arms.

Strains of mycobacterium ulcerans isolated from different clinical forms of the disease in a particular geographical region appear identical, suggesting that a host of factors may play an important role in determining the different clinical presentations.

Because of the local immuno-suppressive properties of mycolactone, or perhaps as a result of other unknown mechanisms, the disease progresses with no pain and fever, which may partly explain why those affected often do not seek prompt treatment.

However, without treatment massive ulcers result, with the classical, undermined borders. Sometimes the bone is affected causing gross deformities.

When lesions heal, scarring may cause restricted movement of limbs and other permanent disabilities in about a quarter of patients.