A new initiative to map a little known disease brings hope of elimination

Map showing the environmental suitability and probability of podoconiosis infections in Ethiopia. Areas in red indicate regions with high levels of podoconiosis infection
Even amongst public health professionals podoconiosis (or endemic non-filarial elephantiasis) is one of the more neglected of the neglected tropical diseases (NTDs).  But much like the better-known polio or guinea-worm disease, the elimination of this debilitating condition is within sight. This eradication is only possible if proper clinical management and preventative
measures can be effectively targeted at the communities affected.

To enable this targeting, researchers from LASER are part of an international effort to develop the first Global Atlas of Podoconiosis.

Podoconiosis is a non-infectious geochemical disease caused by chronic exposure to red clay soils derived from volcanic rock. Irritant particles are absorbed through the feet and collect in the lymphatic vessels and nodes of the lower legs, causing swelling, pain, immobility and disfigurement. Sufferers are often misdiagnosed with lymphatic filarias which though caused by parasitic worms results in similar disfigurements.

It isn’t currently known exactly how many people suffer from podoconiosis, estimates put it at around 4 million people mainly in tropical countries of Africa, Central and South America, and southeast Asia.

In Ethiopia and north-west Cameroon podoconiosis is endemic affecting 4-8% of the population. At these levels of infection, alongside the debilitated clinical effects, the disease poses an immense economic burden, with estimated costs to Ethiopia’s economy of US$208 million per year.

Podoconiosis is one of the NTDs with a clear potential for elimination: it is easily preventable if shoes are consistently worn and early stages can be successfully treated. Currently, control efforts are hampered by a lack of information on geographical distribution. Maps have long been crucial in the planning of disease control. They help in identifying those populations most at risk from NTDs, ensuring they receive treatment, and helping track progress in control.

With funding from the Wellcome Trust, researchers from Ethiopia, Kenya, UK and the US will be pooling their expertise to develop the Global Atlas of Podoconiosis to better enable policy makers and public health implementers to target their control and elimination efforts.

Lead researcher for the atlas is Dr Kebede Deribe from Brighton & Sussex Medical School, “This collaborative effort will lead to an end to the neglect of podoconiosis. The much needed atlas will be used as an advocacy tool to develop an evidence-based global strategy and case for investment. I believe the atlas will provide an important basis for expanding prevention and treatment services of podoconiosis and complement the global elimination of lymphatic filariasis.”

Over the course of the next 5 years the atlas will define the epidemiology and distribution of podoconiosis globally. Working closely with endemic countries, the WHO and development partners, the project will collate all globally available epidemiological data. Through the application of cutting geostatistical models and machine learning approaches the global limits of the disease
will be defined and the population at risk and burden of the disease estimated for the first time.

In-line with the WHO’s call for integration of NTD control efforts the project is integrating podoconiosis mapping with the ongoing mapping of other NTDs.

The benefit of this mapping on the diagnosis and treatment of other NTDs is emphasised by LASER’s Dr Jorge Cano, “Until very recently, most elephantiasis cases in Ethiopia were wrongly attributed to lymphatic filariasis. Analysis by Dr. Kebede Deribe , in collaboration with LASER , identified podoconiosis as the main cause. An open access map which enables users to identify disease hotspots will be an invaluable resource for the targeting of both podoconiosis and LF treatment and prevention programmes. ”

Once completed the atlas will provide vital evidence of the geographical distribution and burden of podoconiosis globally, and provide an important basis for expanding prevention and treatment services on the path towards a world without podoconiosis.

Further resources

 

Francis Peel, 03/05/2017

Comments are closed.