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Interventions to improve water quality for preventing diarrhoea

  1. Thomas F Clasen1,*,
  2. Kelly T Alexander1,
  3. David Sinclair2,
  4. Sophie Boisson3,
  5. Rachel Peletz4,
  6. Howard H Chang5,
  7. Fiona Majorin3,
  8. Sandy Cairncross6

Editorial Group: Cochrane Infectious Diseases Group

Published Online: 20 OCT 2015

Assessed as up-to-date: 11 NOV 2014

DOI: 10.1002/14651858.CD004794.pub3


How to Cite

Clasen TF, Alexander KT, Sinclair D, Boisson S, Peletz R, Chang HH, Majorin F, Cairncross S. Interventions to improve water quality for preventing diarrhoea. Cochrane Database of Systematic Reviews 2015, Issue 10. Art. No.: CD004794. DOI: 10.1002/14651858.CD004794.pub3.

Author Information

  1. 1

    Rollins School of Public Health, Emory University, Department of Environmental Health, Atlanta, GA, USA

  2. 2

    Liverpool School of Tropical Medicine, Department of Clinical Sciences, Liverpool, UK

  3. 3

    London School of Hygiene & Tropical Medicine, Faculty of Infectious and Tropical Diseases, London, UK

  4. 4

    Aquaya Institute, Nairobi, Kenya

  5. 5

    Rollins School of Public Health, Emory University, Department of Biostatistics and Bioinformatics, Atlanta, GA, USA

  6. 6

    London School of Hygiene & Tropical Medicine, Department of Disease Control, Faculty of Infectious and Tropical Diseases, London, UK

*Thomas F Clasen, Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA, 30322, USA. thomas.clasen@lshtm.ac.uk.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 20 OCT 2015

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Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Laienverständliche Zusammenfassung
  5. Laički sažetak
  6. Резюме на простом языке

Background

Diarrhoea is a major cause of death and disease, especially among young children in low-income countries. In these settings, many infectious agents associated with diarrhoea are spread through water contaminated with faeces.

In remote and low-income settings, source-based water quality improvement includes providing protected groundwater (springs, wells, and bore holes), or harvested rainwater as an alternative to surface sources (rivers and lakes). Point-of-use water quality improvement interventions include boiling, chlorination, flocculation, filtration, or solar disinfection, mainly conducted at home.

Objectives

To assess the effectiveness of interventions to improve water quality for preventing diarrhoea.

Search methods

We searched the Cochrane Infectious Diseases Group Specialized Register (11 November 2014), CENTRAL (the Cochrane Library, 7 November 2014), MEDLINE (1966 to 10 November 2014), EMBASE (1974 to 10 November 2014), and LILACS (1982 to 7 November 2014). We also handsearched relevant conference proceedings, contacted researchers and organizations working in the field, and checked references from identified studies through 11 November 2014.

Selection criteria

Randomized controlled trials (RCTs), quasi-RCTs, and controlled before-and-after studies (CBA) comparing interventions aimed at improving the microbiological quality of drinking water with no intervention in children and adults.

Data collection and analysis

Two review authors independently assessed trial quality and extracted data. We used meta-analyses to estimate pooled measures of effect, where appropriate, and investigated potential sources of heterogeneity using subgroup analyses. We assessed the quality of evidence using the GRADE approach.

Main results

Forty-five cluster-RCTs, two quasi-RCTs, and eight CBA studies, including over 84,000 participants, met the inclusion criteria. Most included studies were conducted in low- or middle-income countries (LMICs) (50 studies) with unimproved water sources (30 studies) and unimproved or unclear sanitation (34 studies). The primary outcome in most studies was self-reported diarrhoea, which is at high risk of bias due to the lack of blinding in over 80% of the included studies.

Source-based water quality improvements

There is currently insufficient evidence to know if source-based improvements such as protected wells, communal tap stands, or chlorination/filtration of community sources consistently reduce diarrhoea (one cluster-RCT, five CBA studies, very low quality evidence). We found no studies evaluating reliable piped-in water supplies delivered to households.

Point-of-use water quality interventions

On average, distributing water disinfection products for use at the household level may reduce diarrhoea by around one quarter (Home chlorination products: RR 0.77, 95% CI 0.65 to 0.91; 14 trials, 30,746 participants, low quality evidence; flocculation and disinfection sachets: RR 0.69, 95% CI 0.58 to 0.82, four trials, 11,788 participants, moderate quality evidence). However, there was substantial heterogeneity in the size of the effect estimates between individual studies.

Point-of-use filtration systems probably reduce diarrhoea by around a half (RR 0.48, 95% CI 0.38 to 0.59, 18 trials, 15,582 participants, moderate quality evidence). Important reductions in diarrhoea episodes were shown with ceramic filters, biosand systems and LifeStraw® filters; (Ceramic: RR 0.39, 95% CI 0.28 to 0.53; eight trials, 5763 participants, moderate quality evidence; Biosand: RR 0.47, 95% CI 0.39 to 0.57; four trials, 5504 participants, moderate quality evidence; LifeStraw®: RR 0.69, 95% CI 0.51 to 0.93; three trials, 3259 participants, low quality evidence). Plumbed in filters have only been evaluated in high-income settings (RR 0.81, 95% CI 0.71 to 0.94, three trials, 1056 participants, fixed effects model).

In low-income settings, solar water disinfection (SODIS) by distribution of plastic bottles with instructions to leave filled bottles in direct sunlight for at least six hours before drinking probably reduces diarrhoea by around a third (RR 0.62, 95% CI 0.42 to 0.94; four trials, 3460 participants, moderate quality evidence).

In subgroup analyses, larger effects were seen in trials with higher adherence, and trials that provided a safe storage container. In most cases, the reduction in diarrhoea shown in the studies was evident in settings with improved and unimproved water sources and sanitation.

Authors' conclusions

Interventions that address the microbial contamination of water at the point-of-use may be important interim measures to improve drinking water quality until homes can be reached with safe, reliable, piped-in water connections. The average estimates of effect for each individual point-of-use intervention generally show important effects. Comparisons between these estimates do not provide evidence of superiority of one intervention over another, as such comparisons are confounded by the study setting, design, and population.

Further studies assessing the effects of household connections and chlorination at the point of delivery will help improve our knowledge base. As evidence suggests effectiveness improves with adherence, studies assessing programmatic approaches to optimising coverage and long-term utilization of these interventions among vulnerable populations could also help strategies to improve health outcomes.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Laienverständliche Zusammenfassung
  5. Laički sažetak
  6. Резюме на простом языке

Interventions to improve water quality and prevent diarrhoea

This Cochrane Review summarizes trials evaluating different interventions to improve water quality and prevent diarrhoea. After searching for relevant trials up to 11 November 2014, we included 55 studies enrolling over 84,000 participants. Most included studies were conducted in low- or middle-income countries (LMICs) (50 studies), with unimproved water sources (30 studies), and unimproved or unclear sanitation (34 studies).

What causes diarrhoea and what water quality interventions might prevent diarrhoea?

Diarrhoea is a major cause of death and disease, especially among young children in low-income countries where the most common causes are faecally contaminated water and food, or poor hygiene practices.

In remote and low-income settings, source-based water quality improvement may include providing protected groundwater (springs, wells, and bore holes) or harvested rainwater as an alternative to surface sources (rivers and lakes). Alternatively water may be treated at the point-of-use in people's homes by boiling, chlorination, flocculation, filtration, or solar disinfection. These point-of-use interventions have the potential to overcome both contaminated sources and recontamination of safe water in the home.

What the research says

There is currently insufficient evidence to know if source-based improvements in water supplies, such as protected wells and communal tap stands or treatment of communal supplies, consistently reduce diarrhoea in low-income settings (very low quality evidence). We found no trials evaluating reliable piped-in water supplies to people's homes.

On average, distributing disinfection products for use in the home may reduce diarrhoea by around one quarter in the case of chlorine products (low quality evidence), and around a third in the case of flocculation and disinfection sachets (moderate quality evidence).

Water filtration at home probably reduces diarrhoea by around a half (moderate quality evidence), and effects were consistently seen with ceramic filters (moderate quality evidence), biosand systems (moderate quality evidence) and LifeStraw® filters (low quality evidence). Plumbed-in filtration has only been evaluated in high-income settings (low quality evidence).

In low-income settings, distributing plastic bottles with instructions to leave filled bottles in direct sunlight for at least six hours before drinking probably reduces diarrhoea by around a third (moderate quality evidence).

Research assessing the effects of household connections and chlorination at the point of delivery will help improve our knowledge base. Evidence indicates the more people use the various interventions for improving water quality, the larger the effects, so research into practical approaches to increase coverage and help assure long term use of them in poor groups will help improve impact.

 

Laienverständliche Zusammenfassung

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Laienverständliche Zusammenfassung
  5. Laički sažetak
  6. Резюме на простом языке

Maßnahmen zur Verbesserung der Wasserqualität und zur Vorbeugung von Durchfall

In diesem Cochrane Review werden Studien zusammengefasst, die verschiedene Maßnahmen zur Verbesserung der Wasserqualität und zur Vorbeugung von Durchfall bewerten. Die Recherche nach relevanten Studien bis zum 11. November 2014 ergab 55 Studien mit mehr als 84.000 Teilnehmern. Die meisten der eingeschlossenen Studien wurden in Ländern mit geringem oder mittlerem Einkommen (LMIC, Englisch: low or middle income countries) durchgeführt, in denen Wasser aus hygienisch bedenklichen Quellen verwendet wird (30 Studien) und eine bedenkliche oder unklare Hygienelage besteht (34 Studien).

Was sind die Ursachen von Durchfall und welche Maßnahmen, die an der Wasserqualität ansetzen, können Durchfallerkrankungen vorbeugen?

Durchfallerkrankungen sind eine Hauptursache für Tod und Krankheit, vor allem bei Kleinkindern in Ländern mit geringem Einkommen. Die Hauptgründe für Durchfall sind dort durch Fäkalien verunreinigtes Wasser und Lebensmittel oder mangelhafte Hygienepraktiken.

In abgelegenen Gegenden mit geringem Einkommen könnte eine quellenbasierte Verbesserung der Wasserqualität darin bestehen, geschützte Grundwasserressourcen zu erschließen (Quellen, Brunnen und Wasserbohrungen) oder gesammeltes Regenwasser als Alternative zu Oberflächenwasser (Flüssen und Seen) zur Verfügung zu stellen. Als weitere Alternative kann das Wasser direkt vor der Verwendung bei den Menschen zu Hause durch Aufkochen, Chlorung, Flockung, Filtration oder solare Desinfektion behandelt werden. Diese Maßnahmen direkt vor der Wasserverwendung bergen das Potential, sowohl kontaminierten (verschmutzten) Quellen entgegenzuwirken als auch der erneuten Kontaminierung von sauberem Wasser in den Häusern.

Was sagt die Forschung?

Derzeit liegt keine ausreichende Evidenz vor, um zu entscheiden, ob eine quellenbasierte Verbesserung der Wasserversorgung, beispielsweise durch gefasste Brunnen, kommunale Zapfanlagen oder eine Behandlung der kommunalen Wasserversorgung Durchfallerkrankungen in einkommensschwachen Gebieten nachhaltig reduzieren kann (Evidenz von sehr niedriger Qualität). Wir fanden keine Studien, in denen eine zuverlässige Wasserversorgung über Leitungen in die Häuser der Menschen untersucht wurde.

Durch die Verteilung von Desinfektionsprodukten zum Gebrauch in den Häusern kann das Auftreten von Durchfallerkrankungen um durchschnittlich ein Viertel durch Chlorprodukte (Evidenz niedriger Qualität) und um etwa ein Drittel durch Flockung und Desinfektionsmittelbeutel (Evidenz moderater Qualität) gesenkt werden.

Eine Wasserfiltration in den Häusern senkt das Durchfallrisiko wahrscheinlich um etwa die Hälfte (Evidenz moderater Qualität). Nachhaltige Effekte konnten bei Keramikfiltern (Evidenz moderater Qualität), Bio-Sand-Wasserfiltern (Evidenz moderater Qualität) und LifeStraw®-Filtern (Evidenz niedriger Qualität) festgestellt werden. Filter in Festwasseranschlüssen wurden nur in einkommensstarken Gegenden untersucht (Evidenz niedriger Qualität).

Durch die Verteilung von Plastikflaschen in einkommensschwachen Gebieten mit der Anweisung, die gefüllten Flaschen mindestens sechs Stunden dem direkten Sonnenlicht auszusetzen, bevor das Wasser getrunken wird, kann das Auftreten von Durchfallerkrankungen wahrscheinlich um etwa ein Drittel gesenkt werden (Evidenz moderater Qualität).

Forschungsarbeiten zur Untersuchung der Effekte von Hausanschlüssen und von Chlorung am Entnahmepunkt wird dazu beitragen, unsere Wissensgrundlage zu erweitern. Die Evidenz legt den Schluss nahe, je mehr Menschen Gebrauch von den verschiedenen Maßnahmen zur Verbesserung der Wasserqualität machen, desto größer ist auch die Wirkung. Die Forschung an praktischen Ansätzen zu einer flächendeckenderen Verbreitung der Maßnahmen und einem langfristigen Einsatz in armen Gegenden wird ihren Beitrag zu einer Wirkungssteigerung leisten.

Anmerkungen zur Übersetzung

I. Noack, freigegeben durch Cochrane Schweiz.

 

Laički sažetak

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Laienverständliche Zusammenfassung
  5. Laički sažetak
  6. Резюме на простом языке

Intervencije za poboljšanje kvalitete vode i sprečavanje proljeva

Ovaj Cochrane pregled sažima rezultate istraživanja u kojima su ispitane različite intervencije za poboljšanje kvalitete vode i sprječavanje proljeva. Nakon potrage za odgovarajućim ispitivanjima do 11. studenog 2014. godine, uključeno je 55 studija u kojima je sudjelovalo preko 84.000 sudionika. Većina uključenih studija provedena je zemljama s niskim ili srednjim dohotkom (50 studija), s neobrađenim izvorima vode (30 studija), i neobrađenim ili nejasnim sanitarijama (34 studije).

Što uzrokuje proljev te koja intervencija kvalitete vode može spriječiti proljev?

Proljev je značajan uzrok smrti i bolesti, pogotovo kod male djece u zemljama niskog dohotka gdje su najčešći uzrok fekalijama kontaminirana voda i hrana, ili loše provođenje higijene.

U udaljenim i siromašnim područjima poboljšanje izvora vode za podizanje njene kvalitete može uključivati dovod zaštićene podzemne vode (izvori, bunari i jame) ili sakupljanje oborinske vode kao alternative površinskim izvorima vode (rijeke i jezera). Još je jedna mogućnost obrada vode na mjestu uporabe u domovima kuhanjem, kloriranjem, flokulacijom, filtracijom, ili solarnom dezinfekcijom. Ovakve intervencije imaju potencijal riješiti i problem kontaminacije izvora i ponovne kontaminacije pitke vode u kući.

Rezultati pronađenih istraživanja

Trenutno ne postoji dovoljno dokaza za odgovor na pitanje da li metode poboljšavanja izvora vode, kao što je zaštićeni bunar i komunalna slavina na dodir ili tretman komunalnih pomagala, dosljedno smanjuju proljev u okruženjima s niskim primanjima (dokazi vrlo niske kvalitete). Nisu pronađena istraživanja koja ocjenjuju pouzdanost opskrbe vode u domovima pomoću cijevi.

U prosjeku, distribucija proizvoda za dezinfekciju za korištenje u kući može smanjiti proljev za oko jednu četvrtinu u slučaju proizvoda koji se temelje na kloru (niska kvaliteta dokaza), a oko trećine u slučaju flokulacije i dezinfekcije vrećicama (dokazi umjerene kvalitete).

Filtriranje vode u kući vjerojatno smanjuje proljev za oko pola (dokazi umjerene kvalitete), a učinci su se stalno vidjeli s keramičkim filterima (dokazi umjerene kvalitete), sustava s bio-pijeskom (dokazi umjerene kvalitete) i LifeStraw ® filtera (dokazi niske kvalitete). Mjerenje filtracije samo je ocijenjeno u okruženjima s visokim dohotkom (dokazi niske kvalitete).

U okruženjima s niskim dohotkom, dijeljenje plastičnih boca s uputama da ih se ostavi napunjene na izravnom suncu najmanje šest sati prije konzumacije vjerojatno smanjuje proljev za oko trećinu (dokazi umjerene kvalitete).

Buduća istraživanja koje procjenjuje učinke veze domaćinstva i kloriranja na mjestu isporuke pomoći će nam u dobivanju novih spoznaja. Dokazi pokazuju da što više ljudi koristi različite intervencije za poboljšanje kvalitete vode, veći su učinci, tako da istraživanja praktičnih pristupa povećavaju pokrivenost i pomažu osigurati dugoročno korištenje pa će u siromašnim skupinama poboljšati učinak.

Bilješke prijevoda

Hrvatski Cochrane
Prevela: Božena Armanda
Ovaj sažetak preveden je u okviru volonterskog projekta prevođenja Cochrane sažetaka. Uključite se u projekt i pomozite nam u prevođenju brojnih preostalih Cochrane sažetaka koji su još uvijek dostupni samo na engleskom jeziku. Kontakt: cochrane_croatia@mefst.hr

 

Резюме на простом языке

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Laienverständliche Zusammenfassung
  5. Laički sažetak
  6. Резюме на простом языке

Мероприятия по улучшению качества воды и предотвращению диареи

Этот Кокрейновский обзор обобщает результаты испытаний, оценивающих различные мероприятия по улучшению качества воды и предотвращению диареи. После поиска всех соответствующих исследований по 11 ноября 2014 года, мы включили 55 исследований с участием более 84000 человек. Большинство включенных исследований были проведены в странах с низким или средним уровнем дохода (СНСД) (50 исследований), с не улучшенными источниками воды (30 исследований), и с не улучшенными или неясными санитарными условиями (34 исследований).

Что вызывает диарею и какие вмешательства по повышению качества воды могут предотвратить диарею?

Диарея является одной из основных причин смерти и болезней, особенно среди детей в странах с низким уровнем доходов, где наиболее распространенными причинами являются загрязнение фекалиями воды и пищи, или плохие практики (стандарты) гигиены.

В отдаленных и малообеспеченных условиях, улучшение качества источников воды может включать в себя предоставление защиты грунтовых вод (родники, колодцы и скважины) или заготовку дождевой воды в качестве альтернативы поверхностным источникам (реки и озера). В качестве альтернативы, воду могут обрабатывать по месту использования (в домах людей) такими методами, как кипячение, хлорирование, флокуляция, фильтрация, или солнечная дезинфекция. Эти меры могут потенциально помочь в преодолении обоих видов загрязнения (контаминации): как загрязнения воды в источнике, так и вторичного загрязнения безопасной воды в домашних условиях.

О чем говорит это исследование

В настоящее время существует недостаточно доказательств, чтобы знать, снижают ли меры по улучшению источников водоснабжения, такие как защищенные колодцы и стояки коммунальных кранов (колонки) или обработка средств/источников коммунального водоснабжения, частоту диареи в странах с низким уровнем дохода (доказательства очень низкого качества). Мы не нашли ни одного испытания, оценивающего надежные источники водоснабжения, предоставляющие воду в дома людей.

В среднем, распространение дезинфицирующих средств для использования в домашних условиях может уменьшить частоту диареи примерно на четверть при использовании продукции, содержащей хлор (доказательства низкого качества), и примерно на треть при использовании флокуляции и дезинфекционных саше (доказательства среднего качества).

Фильтрация воды в домашних условиях, вероятно, снижает риск развития диареи примерно наполовину (доказательства среднего качества), и эффективность её была очевидна с хорошим постоянством при использовании керамических фильтров (доказательства среднего качества ), и систем биосанд (доказательства среднего качества ), и фильтров LifeStraw® (доказательства низкого качества). Системы канализации с фильтрацией были оценены только в странах с высоким уровнем доходов (доказательства низкого качества ).

В странах с низким доходом, распространение пластиковых бутылок с инструкциями по помещению заполненных водой бутылок под прямые солнечные лучи, как минимум, на шесть часов перед питьем, вероятно, снижает частоту диареи примерно на треть (доказательства среднего качества).

Исследование по оценке влияния бытовых связей и хлорирования воды по месту доставки воды поможет улучшить нашу базу знаний. Доказательства показывает, что чем больше люди используют различные меры по улучшению качества воды, тем больше их эффективность, поэтому исследования практических подходов к увеличению охвата и помощи в обеспечении их длительного использования в бедных группах, поможет улучшить это положительное воздействие.

Заметки по переводу

Перевод: Конг Хонг Хань. Редактирование: Зиганшина Лилия Евгеньевна. Координация проекта по переводу на русский язык: Cochrane Russia - Кокрейн Россия (филиал Северного Кокрейновского Центра на базе Казанского федерального университета). По вопросам, связанным с этим переводом, пожалуйста, обращайтесь к нам по адресу: lezign@gmail.com