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.
In 2014, it was declared the 2000–2015 Millennium Development Goal – to reduce by half those without access to “improved” supplies – was met for water, but not for sanitation. The anticipated WASH Sustainable Development Goals (SGD) will focus on increasing piped-on-premises supplies, eliminating open defecation, ensuring microbiological water safety, reducing disparities, and ensuring sustainability in households and institutions.20 The long-term WASH improvements necessary to achieve the SDGs will greatly reduce the global cholera burden. In the interim, community and household-level WASH interventions are one critical part of a comprehensive strategy to reduce cholera transmission. Further innovation (including developing creating hygiene promotion strategies), implementation, evaluation (including disease and water quality outcome metrics), and research, particularly on ensuring adoption and investigating holistic WASH programming, will be needed to realize their full potential.
References
1 Cutler D, Miller G.The role of public health improvements in health advances: the twentieth-century United States. Demography 2005, 42, (1), 1–22.
2 WHO/UNICEF Progress on Drinking Water and Sanitation: 2015 Update and MDG Assessment; World Health Organization and UNICEF: Geneva, Switzerland and New York City, NY, USA, 2015.
3 Onda K., LoBuglio J, Bartram, J. Global access to safe water: accounting for water quality and the resulting impact on MDG progress. Int J Environ Res Public Health 2012, 9, (3), 880–894.
4 See No. 40, 2015, pp. 517–544.
5 Nygren, B, L Blackstock A.J, Mintz E.D. Cholera at the crossroads: the association between endemic cholera and national access to improved water sources and sanitation. Am J Trop Med Hyg 2014, 91, (5), 1023–1028.
6 UNICEF Cholera Toolkit; UNICEF: New York, NY, USA, 2013. 7 Taylor D. N, Kahawita T, Cairncross S, Ensink J. The impact of water, sanitation, and hygiene interventions to control cholera: A systematic review. PloS ONe 2015, 10(8): e0135676. doi:10.1371/journal.pone.0135676.
7 Taylor D. N, Kahawita T, Cairncross S, Ensink J. The impact of water, sanitation, and hygiene interventions to control cholera: A systematic review. PloS ONe 2015, 10(8): e0135676. doi:10.1371/journal.pone.0135676.
8 Colwell, R. R, et al. Reduction of cholera in Bangladeshi villages by simple filtration. Proc Natl Acad Sci U S A 2003, 100, (3), 1051–1055.
9 Conroy R.M, Meegan M. E, Joyce T, McGuigan K, Barnes J. Solar disinfection of drinking water protects against cholera in children under 6 years of age. Arch Dis Child, 2001, 85, (4), 293–295.
10 Deb B. C et al. Studies on interventions to prevent eltor cholera transmission in urban slums. Bull World Health Organ 1986, 64, (1), 127–131.
11 O’Connor K. A, et al. Risk factors early in the 2010 cholera epidemic, Haiti. Emerg Infect Dis 2011, 17, (11), 2136–2138.
12 Jeandron A, et al. Water supply interruptions and suspected cholera incidence: a time-series regression. PLoS Med [in press]. 13 Cavallaro E. C et al. Evaluation of pot-chlorination of wells during a cholera outbreak, Bissau, Guinea-Bissau, 2008. J Water Health 2011, 9, (2), 394–402.
14 Luby S, Islam M. S, Johnston R. Chlorine spot treatment of flooded tube wells, an efficacy trial. J Appl Microbiol 2006, 100, (5), 1154–1158.
15 Rowe A. K., Angulo F. J. Chlorinating well water with liquid bleach was not an effective water disinfection strategy in Guinea-Bissau. International Journal of Environmental Health Research 1998, (8), 339–340.
16 Godfrey S, McCaffrey L, Obika A, Becks M. The effectiveness of point-source chlorination in improving water quality in internally displaced communities in Angola. UK Journal of the Chartered Institution of Water and Environmental Managers, 2002.
17 Lantagne D, Clasen T. Use of household water treatment and safe storage methods in acute emergency response: case study results from Nepal, Indonesia, Kenya, and Haiti. Environ Sci Technol 2012, 46, (20), 11 352– 11 360.
18 Yates T. M, Armitage E, Lehmann, L.V, Branz, A. J, Lantagne, D. S. Effectiveness of chlorine dispensers in emergencies: case study results from Haiti, Sierra Leone, Democratic Republic of Congo, and Senegal. Environ Sci Technol 2015, 49, (8), 5115–5122.
19 Agung H, Berndtsson M. Oxfam’s first Peepoo intervention in the Philippines; Oxfam, Peepoople: 2014.
20 WSP WASH Post-2015 proposed targets and indicators for drinking-water, sanitation and hygiene; World Bank Water and Sanitation Program: 2014.
