Podoconiosis: Endemic Non-filarial Elephantiasis

Podoconiosis is an endemic, non-filarial lymphoedema of the lower limb which needs to be differentiated from lymphatic filariasis (LF), lymphoedema of systemic disease and other causes of localized lymphoedema. The disease, affecting genetically susceptible individuals who go barefoot, is linked to long-term exposure to red clay soil. Interactions between genetic and environmental factors trigger an inflammatory response that leads to lymphoedema and fibrosis. Patients with podoconiosis develop signs and symptoms in the second and third decades of life with the disease being common up to the sixth decade. The disease is mostly bilateral but asymmetrical and mostly limited to below the knees. Globally, there is current evidence of podoconiosis in 17 countries across tropical Africa, central and South America and Southeast Asia. In Africa, podoconiosis has been reported in 12 countries where 114.5 million people live. Tropical African countries bear the highest disease burden with about one and a half million people living with podoconiosis in Ethiopia, a further 40,000 in Cameroon and 7000 in Rwanda. The key strategies for podoconiosis control are prevention of contact with soil (primary prevention) and lymphoedema morbidity management (secondary and tertiary prevention). The main challenge faced in podoconiosis control is lack of awareness that the condition exists and that it is different from LF and other main causes of lymphoedema in the tropics. Mapping of podoconiosis is progressing, and development of a global atlas of podoconiosis is critical. Evidence from the past 5 years suggests that podoconiosis is amenable to public health interventions such as footwear and hygiene-based morbidity management, which reduce acute clinical episodes. The development of a global strategy is important to galvanize the momentum achieved over the past 5 years. Mapping of disease must be accompanied by development of national control programmes to deliver preventive and treatment interventions. Controlling podoconiosis is achievable given the absence of a biological agent or vector also needing control, the relatively small global scale of the problem, and the safe means of podoconiosis prevention and control.