By Dr Michael Templeton, Reader in Public Health Engineering, Department of Civil and Environmental Engineering, Imperial College London
Wednesday, May 25th 2016 marks Africa Day, the 53rd anniversary of the founding of the Organisation of African Unity, the forerunner of the African Union. There have been so many wonderful developments in Africa in the last 53 years, but sadly the quality of life of many of the poorest people in Africa continues to be limited by the burden of a group of debilitating diseases known collectively as neglected tropical diseases (NTDs), which have afflicted millions of Africans since ancient times. Therefore, it is hugely exciting that in 2012 The World Health Assembly put forward an important resolution to not only control but completely eliminate one such NTD, schistosomiasis.
It has been estimated that 200 million people in developing countries, most of whom live in Africa, are infected with the parasite causing schistosomiasis, which manifests itself in a range of symptoms, including enlargement of the liver and spleen, anaemia, increased risk of bladder cancer, exacerbation of the transmission of HIV and its progression to AIDS, and in extreme cases seizures. The parasite lives within infected people, with aquatic snails acting as intermediate hosts and releasing cercariae (the larval form of the parasite) into water bodies, which then penetrate the skin of other people who come in contact with the contaminated water. Preventing people from coming into contact with contaminated water and preventing urine and faeces from passing into water bodies should stop this cycle, however most endemic countries lack adequate water and sanitation provision. Achieving the WHA’s ambitious elimination goal will therefore require a coordinated, multi-disciplinary strategy, involving mass preventive chemotherapy with the drug praziquantel but also improving access to water, sanitation and hygiene (WASH).
To this end, Dr Jack Grimes and Dr Michael Templeton in the Department of Civil and Environmental Engineering at Imperial College London are currently working with colleagues in the Schistosomiasis Control Initiative in the School of Public Health and other partners to determine the best inter-disciplinary interventions for controlling, and hopefully even some day fully eliminating, schistosomiasis in Ethiopia. Their recent paper published in PLOS Neglected Tropical Diseases summarises a 2013-14 Ethiopian national mapping programme and presents data collected on the health (schistosomiasis and soil-transmitted helminthiases) and school WASH conditions of over 80,000 children in over 1,600 schools across the country. An important conclusion was that the most effective types of WASH interventions can differ depending on the disease, because of differences in transmission pathways between diseases. Furthermore, different WASH interventions might be needed for the same disease but in different settings; for example, in some communities there may be a need for safe laundry, bathing or recreational swimming facilities to minimise exposure to a contaminated water body, whereas in others the priority might be to build improved latrine blocks, as shown below, so that the current dilapidated, unhygienic latrines no longer act as a major focal point for disease transmission.
The hope is that the experience and knowledge arising from this ongoing collaboration will guide on-the-ground WASH and health professionals towards the most effective, community-level, combined chemotheraphy and WASH interventions so that Africa can move closer to finally eliminating schistosomiasis.