What is Cholera and why does it matter?
Cholera is a diarrhoeal disease caused by the bacteria Vibrio cholerae. The infection if untreated can within hours, cause diarrhoea and vomiting leading to severe dehydration and in some cases death. Cholera is easily treated with oral rehydration solution so why then are there still so many cases reported every year? In fact the World Health Organisation (WHO) estimates that there are between 3-5 million cholera cases and 100,000 deaths every year, of which only a fraction are officially reported.
The battle against cholera has been fought since it was first reported in Asia in 1817. The work of Dr. John Snow during the outbreaks in London’s Soho district in the 1850’s focussed attention to its water-borne transmission route and highlighted the need for improved water supply, sanitation and hygiene (WASH) infrastructure, which we enjoy today. These days, cholera outbreaks are more likely to occur following emergencies, particularly in those countries where WASH services have been damaged or still remain an unmet need. Cholera knows no boundaries. It is spread by multiple pathways, mainly through ingestion of contaminated water and food and can decimate an unprepared population such as was seen in Haiti following the earthquake in 2010.
The Environmental Health Group strives to continue John Snow’s work to find evidence-based practical solutions to control and prevent this devastating disease.
Key research and contributions to this area:
Systematic literature review of WASH activities to prevent Cholera
This systematic literature review conducted by Sandy Cairncross, Jeroen Ensink and Tanya Kahawita evaluated the impact of WASH activities undertaken to prevent and control cholera outbreaks in Guinea-Conakry and Guinea-Bissau. The evaluation had three aims: 1) To assess whether the WASH interventions have resulted in an improved understanding of the risk factors and mode of transmission of cholera among the target population, policy makers and those involved in the implementation of the cholera control activities, 2) To assess whether the WASH interventions have resulted in an improvement in water quality, sanitation and hygiene in those households and neighbourhoods affected by the cholera epidemic and 3) To provide recommendations, based on the findings of the field evaluation and a literature review, for the improvement of the current cholera control program.
Current research in this area:
Aurelie Jeandron is currently working on an impact evaluation of a large water supply improvement project in Uvira, in Eastern DRC. Funded by the French Development Agency, the European Union, the Veolia Environment Foundation and OXFAM UK, this project aims at improving access and reliability of tap water supply in a cholera endemic area on the shores of Lake Tanganyika. Since 2009, 5’120 cases were admitted to the Cholera Treatment Centre in Uvira, for an estimated population of approximately 205’000 inhabitants.
The impact evaluation will quantify the potential decrease in cholera incidence attributable to the improvements in tap water production (quantity of water produced and production / distribution reliability) and access to private and public taps (96 new community managed public taps). It will also investigate the project impact on time savings due to closer water sources, school absenteeism and hygiene practices.
A controlled interrupted time-series approach will be used in combination with randomization of the intervention roll-out. Repeated cross-sectional surveys and case-control designs will also be used. This impact evaluation will benefit from a strong baseline dataset and detailed mapping of Uvira in 184 neighbourhoods, with geolocalisation of cases since 2009 and water sources (including the only 4’500 taps available in town).
Systematic literature review of the health impact of WASH interventions in cholera outbreak response.
This systematic literature review will review the existing evidence to distil which WASH related activities can be considered best practice during cholera outbreaks.
Publications related to Cholera:
- Cairncross, S., Ensink, J., Kahawita T. Evaluation of the WASH activities undertaken to prevent and control cholera outbreaks in Guinea-Conakry & Guinea-Bissau & systematic literature review. In HUmanitarianResponse. 2009.
- Taylor DL, Kahawita TM, Cairncross S, Ensink JHJ. The Impact of Water, Sanitation and Hygiene Interventions to Control Cholera: A Systematic Review. PLoS ONE. 2015;10(8):e0135676.