Innovative WASH interventions to prevent cholera. Source: WHO Wkly Epid Rec, Oct 2, 2015
Authors: Daniele Lantagne, Andy Bastable, Jeroen H. J. Ensink, and Eric Mintz.
In the late 19th and early 20th centuries, epidemic cholera was virtually eliminated in industrialized countries through municipal water supply with treatment and sanitation infrastructure.1 A century later, in 2014, only 58% of the global population had access to piped-on premises water,2 and an estimated 1.8 billion people (28% of the global population) drank microbiologically contaminated water.3 Within this inadequate water and sanitation context, cholera transmission continues.
In 2014, 32 countries – many of which are struggling with poverty, rapid population growth, and instability – reported cholera transmission.4
A recent model found that national improved water access of 71%, and improved sanitation access of 39%, predicted whether a country would have endemic cholera with 62%–65% sensitivity and specificity.5
As progress is made towards universal access to reliable piped-on-premises water, reducing the remaining cholera burden requires a comprehensive strategy. Community- and household level water, sanitation, and hygiene (WASH) interventions are one part of that strategy.
Common cholera-prevention WASH interventions include: water supply, water treatment (well, pot, or bucket chlorination and household treatment); sanitation options (latrines); and, promotion of hand washing and environmental hygiene.6
The effectiveness of these interventions varies7 : water supply and chlorine-based, filtration, and solar disinfection household options have been shown to reduce cholera transmission among users;8, 9, 10, 11, 12 well/pot chlorination effectively treats water only for a few hours,13, 14, 15 unless chlorine is regularly added;16 there is little research on bucket chlorination, sanitation, and hygiene interventions.
Recent innovations in chlorine-prevention WASH include identification of factors leading to programmatic success, and new product design (such as sourcebased water treatment and personal use sanitation options).
An investigation of 14 household treatment programmes implemented in 4 emergencies (including 3 cholera emergencies) found that reported use ranged from 1% to 93% and effective use (the percentage of recipients who improved their drinking water microbiological quality to international standards) ranged from 0 to 68%.17
The most successful programme provided an effective method (chlorine tablets), with the necessary supplies to use it (bucket and tap), and ongoing training by local community health workers to people using contaminated water who were familiar with chlorination before the emergency. Conversely, the least successful programme distributed only chlorine tablets in a relief kit labeled in English to populations without previous chlorination experience.
Similar results were found in an evaluation of dispensers, an innovative source-based intervention that includes a chlorine dispenser and dosing valve installed at water sources, community education, and chlorine refills. Across seven evaluations in four emergencies (including 3 cholera emergencies), reported dispenser use ranged from 9-97% and effective use from 0 to 81%.18
More effective programmes installed dispensers at point-sources, maintained a high-quality chlorine solution manufacturing and distribution chain, maintained hardware, integrated dispenser projects within larger water programmes, compensated promoters, had experienced staff, worked with local partners to implement the project, conducted ongoing monitoring, and had a sustainability plan.
The Peepoo is a personal, single-use, biodegradable selfsanitizing double-plastic bag toilet. Peepoos contain sufficient powdered urea to inactivate harmful pathogens in urine and feces after 4 weeks, at which time the waste can be used as fertilizer. Peepoos have been used where latrines are not feasible due to population density, and to bridge the gap between emergency onset and latrine construction.19
One emergency programme concluded that products should be pre-positioned before the emergency, all products necessary for use (including a sitting/squatting stool) should be provided to recipients, training for community health workers should occur before distribution, compensation for collection activities should be provided, and that the disposal mechanism and exit strategy should be predefined before distribution.
As can be seen, lessons learned from the programmes described above are similar: WASH interventions can successfully improve water quality, isolate feces from the environment, and reduce the potential for cholera transmission if they are wisely implemented and distributed with appropriate supplies and training to at-risk populations.