There are two groups of microbial agents which cause disease. Actinomycetoma – the form caused by filamentous bacteria (actinomycetes) – responds well to antibiotics (amikacin and co-trimoxazole) and has a 90% cure rate. However eumycetoma – the fungal form – develops into a chronic skin infection which, without treatment, invades the surrounding tissue and bone. Children and young adults, particularly men working outdoors, are most at risk.
Early treatment has a higher chance of being effective, but patients live a long way from health centres and tend to present with advanced disease, if at all, by which time antifungal cure is only 25-35% effective. Treatment is most often followed by surgical removal of the remaining mass and there is a high chance of recurrence, often leading to multiple amputations and ultimately the loss of entire limbs, with the associated risk of complications and death. Current antifungals are expensive and cause serious side effects, and an effective, safe, and affordable curative treatment for use in rural settings is desperately needed.
Ketoconazole and itraconazole are the antifungal agents that are currently in use, however these have serious side effects. Concerns about liver toxicity have lead the FDA and EMA to restrict the use of ketoconazole. Both the duration (twelve months) and cost of treatment are significant barriers to access for patients and health authorities in endemic areas, and as a result drop-out rates are high: at 10,000 USD per annum, the treatment represents between 50-100% of the average annual wage of patients.