Following in the footsteps of famous Newcastle University alumnus Dr John Snow, who identiﬁed cholera as a waterborne disease, researchers used molecular diagnostics in Tanzania to tackle this ancient plague.
Scientists used Newcastle’s innovative suitcase laboratory to study waterborne disease transmission pathways in an informal settlement where cholera is endemic.
In this settlement, pit latrines provide basic on-site sanitation and local groundwater is the main household water source.
The research was published in the journal Environment International, and led by Newcastle University and Ardhi University in Tanzania.
Portable and affordable methods
Professor David Werner, of Newcastle University’s School of Engineering, said: “Following the Covid-19 pandemic, most people will be familiar with methods like qPCR tests, sequencing, and wastewater epidemiology. Already years before Covid we worked with colleagues in Tanzania to make these methods portable and affordable. Our aim was to bring these tools within reach of those facing the greatest water security challenges.”
Joint corresponding author, Dr Shaaban Mrisho Mgana from Ardhi University’s Environmental Engineering Department added: “Pit latrines provide essential onsite sanitation services to millions of people in Dar es Salaam. But there are concerns about their role in infectious disease transmission and impacts on groundwater resources. Using wastewater epidemiology, we demonstrated that about 5% of the population in the settlement were asymptomatic carriers of Vibrio cholerae bacteria.
“With state-of-the-art molecular diagnostics we further showed that human waste is the source of these bacteria in the groundwater below the settlement. We also showed that natural attenuation of bacterial hazards in the subsurface is insufficient to protect the boreholes used by the community from faecal contamination, especially in the rainy season.
“Finally, we devised and demonstrated an affordable hazard mitigation measure by inserting one meter of sand at the bottom of pit latrines, which achieved 90-99.99% removal of Vibrio cholerae and other faecal bacteria from the percolating leachates.”
Cholera is an acute diarrhoeal disease that can kill within hours if left untreated. According to the World Health Organization, researchers have estimated that each year there are 1.3 to 4.0 million cases of cholera, and 21 000 to 143 000 deaths worldwide due to cholera.
Provision of safe water and sanitation is critical to prevent and control the transmission of cholera and other waterborne diseases.
Despite the recognition of the human right to water and sanitation by the United Nations through Resolution 64/292, 3.6 billion people still lacked safely managed sanitation in 2020. This included 1.7 billion without basic sanitation facilities. The Global Challenges Research Fund (GCRF) supports the research collaboration, and is part of the UK’s official development assistance (ODA). It funds cutting-edge research to achieve the United Nations sustainable development goals, including Sustainable Development Goal 6 (SDG6), clean water and sanitation.
What else are we doing?
Newcastle University leads two prestigious Global Research Hubs set up to tackle the world's toughest challenges, the UKRI GCRF Living Deltas Hub and the UKRI GCRF Water Security and Sustainable Development Hub.
The Times Higher Education Impact Rankings 2022 ranked Newcastle University top in the UK, and 8th in the world for action on sustainable development. Dr John Snow must be proud of his alma mater, and those who are following his footsteps.
About Professor David Werner
David is Professor of Environmental Systems Modelling at the School of Engineering, Newcastle University. He works with global partners on the United Nations Sustainable Development Goal 6, clean water and sanitation, and its numerous linkages with the other 16 UNSDGs. Read his CleanWaterResearch blog for more information and the latest updates.
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