WISER-Water Infrastructure for Schistosomiasis-Endemic Regions

Lead Research Organisation: Imperial College London
Department Name: Civil & Environmental Engineering

Abstract

Schistosomiasis, also known as bilharzia or 'snail fever', is a parasitic disease carried by fresh water snails that are infected by one of five varieties of the pararasite Schistosoma. Schistosomiasis is transmitted by human contact with contaminated fresh water that are inhabited by snails carrying the parasite. Larvae, known as cercariae, emerge from the infected snails and swim in the water until they come into contact with an individual and penetrate the skin. The transmission to humans can occur through a range of normal water contact activities such as collection of drinking water, bathing, washing clothes, swimming or fishing. Once inside the body the larvae develop into worms which live in the blood vessels for years. Female worms shed eggs which end up in urine and faeces; if infected individuals urinate or defecate into freshwater bodies, the eggs migrate to snails where they hatch and begin the cycle again. The symptoms of schistosomiasis can include frequent painful and bloody urine, abdominal pain and bloody diarrhoea, inflammation and scarring of the bladder, enlargement of the liver or spleen, and where infection persists, bladder cancer may develop. In children it leads to anemia, malnutrition and learning difficulties, thus dramatically impairing their future quality of life and productivity. It is estimated that 258 million people are infected in 78 countries worldwide, though 90% of the infections occur in Africa. Schistosomiasis kills an estimated 280,000 people annually and ranks second only to malaria as the most common parasitic disease.

Praziquantel is the primary form of treatment, with a single dose of the drug having been shown to reduce the burden of infection and severity of symptoms. However, re-infection will quickly occur when people are re-exposed to contaminated water. Education campaigns about the risks of exposure to contaminated water and improved water supply and sanitation should in theory break the life cycle of the disease. Universal sanitation coverage should prevent the passage of urine and faeces into contaminated water bodies, however there is always a danger of transmission by infected people visiting from elsewhere and urinating or defecating into the water body, or occasional lapses in the usage of sanitation facilities. Mollusciciding has also been suggested as a solution, however there are concerns regarding potential unintended consequences of dosing molluscicides into water bodies and the long-term effectiveness and sustainability of this strategy is questionable, since the snails could return at some point in the future. In some cases there may be alternative water sources (e.g. boreholes) which can be accessed, however often there are no alternative safe water sources available to meet the full water needs of communities in endemic regions. In such cases, therefore, the immediate focus for cutting schistosomiasis transmission must be treating the contaminated freshwater body to provide a safe alternative supply. Unfortunately however, there is very limited and incomplete information available regarding the effectiveness of water treatment processes at removing or inactivating cercariae of different Schistosoma. Also, there are no rapid means for detecting cercariae in water samples and determining their viability, which makes assessing the risk and degree of contamination of a water body and testing the effectiveness of water treatment processes as barriers against cercariae very difficult. This three-year research programme aims to address these gaps in critical knowledge through a collaboration between water engineers, synthetic biologists, parasitologists, and social scientists in the UK, Ethiopia and Tanzania, in the hope of developing invaluable new knowledge to guide the design of sustainable water infrastructure for schistosomiasis-endemic regions.

Planned Impact

In 2013 the World Health Assembly adopted a formal resolution in which it set the goal of eliminating neglected tropical diseases, including schistosomiasis, which has generated a renewed emphasis on the need for more integrated intervention strategies that go beyond simply mass drug administration alone and instead seek to incorporate environmental control strategies such as water supply improvements like the ones that we will focus on here. Our research programme contains objectives which are novel and ambitious scientifically but will also deliver evidence-based recommendations and tools, for impactful application to the goal of schistosomiasis elimination immediately.
Ethiopia and Tanzania, both categorised as being among the Least Developed Countries in the DAC list, are the countries of the partnering institutions in this research, Addis Ababa University and the National Institute for Medical Research, respectively. These countries will directly benefit by the new knowledge arising from the research, which will lead to recommendations for water infrastructure for schistosomiasis-endemic regions of their countries and new biosensor tools for rapid and cheap assessment of contaminated water bodies, as well as capacity-growing through participation in the research and bespoke training workshops and new curriculum development to extend our impact into the future. We will run workshops in both Mwanza and Addis Ababa to disseminate the research aims and findings to as wide an audience as possible and invite relevant in-country and regional stakeholders to contribute to the research. There are many other African countries on the DAC list that have significant schistosomiasis-endemic regions which will also benefit from the knowledge arising from this research. We also want to make sure that the research reaches the poorest of the poor, those afflicted by schistosomiasis, and not just those at the top of decision-making. The inclusion of four low-income case study communities in the research programme will allow opportunities for community members to become aware of the research and directly assist in the research activities.
Schistosomiasis is a disease of extreme poverty and is primarily relevant to the poorest communities in developing countries, many of which lack even basic water supply infrastructure. It is estimated that 258 million people are infected in 78 countries worldwide, though 90% of the infections occur in Africa. Schistosomiasis kills an estimated 280,000 people annually, most of whom live in ODA countries of sub-Saharan Africa, and it ranks second only to malaria as the most common parasitic disease. Overcoming the burden of schistosomiasis would therefore lead to improved health, greater quality of life and increased economic productivity of the afflicted people in these countries. In children, schistosomiasis leads to anemia, malnutrition and learning difficulties, thus limiting economic potential of the countries into the future. While treatment with the drug praziquantel can have immediate beneficial effects, re-infection can occur rapidly if people are re-exposed to contaminated water. The long-term sustainable solution to this challenge ultimately will rely on a combination of drug treatment with provision of safe alternative water supplies to minimise this re-exposure. The proposed research aims to develop the evidence-base necessary to design effective, sustainable water infrastructure to achieve the latter, as well as sensors for assessing risk and monitoring schistosome cercariae contamination levels in freshwater bodies.
The research will contribute to the UK Aid Strategy stated goal of tackling extreme poverty and helping the world's most vulnerable, since schistosomiasis is a disease of extreme poverty, and contribute to Sustainable Development Goals 6 (clean water and sanitation), 3 (good health and wellbeing) and ultimately 1 (no poverty).

Publications

10 25 50
 
Description Royal Society - Royal Society of Chemistry International Exchanges Award
Amount £12,000 (GBP)
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 09/2017 
End 09/2019
 
Description European Researchers' Night at the Natural History Museum 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact The event ran from 4-10 pm on 28 September 2018, with hundreds of attendees. WISER project team members from the Natural History Museum (Aidan Emery and Fiona Allan) explained the research to attendees.
Year(s) Of Engagement Activity 2018
 
Description Nature Live event at the Natural History Museum 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact WISER project team member Aidan Emery and collaborators from Acting for Health spoke to 30 A Level students about the research. This took place on 15 November 2018.
Year(s) Of Engagement Activity 2018
 
Description Presentation on 26 January 2018 to Year 11 students at London Nautical School by WISER project researchers Laura Braun and Lucinda Hazell as part of the Outreach Ambassadors Scheme, aimed at raising knowledge of and enthusiasm for STEM. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Approximately 30 pupils attended the presentation to Year 11 students at London Nautical School by WISER project researchers Laura Braun and Lucinda Hazell as part of the Outreach Ambassadors Scheme, aimed at raising knowledge of and enthusiasm for STEM. It sparked questions and discussion afterwards and was generally well received.
Year(s) Of Engagement Activity 2018