Interventions to improve water quality Interventions to improve water quality to prevent diarrhoeal disease: to prevent diarrhoeal disease:

a systematic review and a systematic review and case study in Colombiacase study in Colombia

Thomas F. ClasenLondon School of Hygiene & Tropical Medicine

Keppel St., London WC1E 7HT, United Kingdomthomas.clasen@lshtm.ac.uk

Girardot, Mayo 2006

3963

2777

1798 15661271

611

0500

10001500200025003000350040004500

Respir

atory

Infec

tions

HIV/A

IDS

Diarrhoe

al Dise

ases

Tuber

culos

isMala

riaMea

sles

Dea

ths

(000

s)Leading Causes of Deaths from Infectious DiseasesLeading Causes of Deaths from Infectious Diseases

2004 World Health Report

9460384458

61996

4648634736

21475

0100002000030000400005000060000700008000090000

100000

Respir

atory

infec

tions

HIV/A

IDS

Diarrh

oeal

disea

ses

Malaria

Tube

rculos

isMea

sles

DA

LYs

(000

s)

Leading Causes of Leading Causes of DALYsDALYs from Infectious Diseasesfrom Infectious Diseases2004 World Health Report

Childhood Mortality by CauseChildhood Mortality by Cause

Black RE, Morris SS & Bryce J (2003). Where and why are 10 million children dying every year? Lancet 361:2226-34.

Environmental Barriers Environmental Barriers to to FaecalFaecal--Oral TransmissionOral Transmission

Primary BarrierPrimary BarrierSanitation (proper excreta Sanitation (proper excreta disposal)disposal)Hygiene (hand washing)Hygiene (hand washing)

Secondary BarriersSecondary BarriersWater quality (treatment & Water quality (treatment & safe storage)safe storage)Water quantity (personal Water quantity (personal and domestic hygiene)and domestic hygiene)Hygiene (especially hand Hygiene (especially hand washing)washing)Proper cooking/food Proper cooking/food handing practiceshanding practices

Emergence of the Emergence of the Dominant ParadigmDominant Paradigm

00--48%48%22%22%1010Improvements in Excreta DisposalImprovements in Excreta Disposal

00--82%82%37%37%88Improvements in Water Quality and AvailabilityImprovements in Water Quality and Availability

00--100%100%25%25%1717Improvements in Water QuantityImprovements in Water Quantity

00--90%90%16%16%99Improvements in Water QualityImprovements in Water Quality

00--100%100%22%22%5353All InterventionsAll Interventions

RangeRangeMedianMedianNo. StudiesNo. StudiesType of InterventionType of Intervention

Reduction Reduction

water supply or excreta disposal improvements (water supply or excreta disposal improvements (EsreyEsrey, 1985), 1985)

Percentage reductions in diarrhoeal morbidity rates attributed tPercentage reductions in diarrhoeal morbidity rates attributed too

Consolidation of the Consolidation of the Dominant ParadigmDominant Paradigm

33%33%6633%33%66HygieneHygiene

20%20%5527%27%77Water QuantityWater Quantity

15%15%4417%17%77Water QualityWater Quality

17%17%2216%16%2222Water Quality and QuantityWater Quality and Quantity

36%36%5522%22%1111SanitationSanitation

30%30%2220%20%77Water and SanitationWater and Sanitation

Reduction Reduction No. StudiesNo. StudiesReductionReductionNo. StudiesNo. Studies

Rigorous StudiesRigorous StudiesAll StudiesAll Studies

Expected reduction in diarrhoeal disease morbidity from Expected reduction in diarrhoeal disease morbidity from improvements in one or more components of water and improvements in one or more components of water and

sanitation (sanitation (EsreyEsrey, 1991), 1991)

Ceramic Filter DesignsCeramic Filter DesignsCandle FilterCandle Filter

Microbiological Microbiological Efficacy:Efficacy:CharincoCharinco, , BoliviaBolivia Mean Fecal Coliform Count

Charinco, Bolivia

917.88

405.59

167.12

375

797

0000

790

0

100

200

300

400

500

600

700

800

900

1000

Baseline March April June July

Sampling Period

Arit

hmet

ic M

ean

FC C

ount

Intervention Group

Control Group

Clasen T, Brown J, Suntura O, Collin S (2004). Safe household water treatment and storage using ceramic drip filters: a randomisedcontrolled trial in rural Bolivia. Water Sci & Tech 50(1): 111-115.

Health Impact: Health Impact: CharincoCharinco, Bolivia, Bolivia

Diarrhoeal Prevalence and 95%CI Charinco, Bolivia

22.7

18.820.3

23.1

21.3

4.1

11.39.7

22.1

4.8

0

5

10

15

20

25

30

35

Baseline Week 7 Week 13 Week 19 Week 25

Surveillance Point

Perc

enta

ge P

reva

lenc

e (7

day

reca

ll)

Control

Intervention

In a six-month randomized controlled trial by First Water and Fundación SumajHuasi in Charinco, Bolivia, diarrhoea prevalence among filter users was 64% lessthan the control group (p<0.001). The reduction was 72% among children under 5(p<0.001)

(Clasen T, Brown J, Suntura O, Collin S, Cairncross S (2004). Reducing diarrhoea through the use of household-based ceramic water filters: a randomized, controlled field trial in rural Bolivia. Am J. Trop Med. & Hyg. 70(6):651-657

Health Impact: Health Impact: ChiChiññiriiri, Bolivia, Bolivia

6.7%

4.1%

7.1%7.5%

4.7%

5.3%

13.2%

2.1%1.5%

3.8%

2.9%

3.1%3.9%

3.2%

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

Baseline Round 1 Round 2 Round 3 Round 4 Round 5 Overall

Surveillance Round

Dia

rrho

ea P

reva

lenc

e

Control

Intervention

In a five-month randomized controlled trial of a pilot intervention by Food for the Hungry, Int’l in rural Bolivia, locally-fabricated water filters using Brazilian ceramic elements were associated with a 45.3% reduction in diarrhoea compared to the control group (p=0.02)

Clasen T, Brown J, Collin S (2006) Preventing diarrhoea with household ceramic water filters: an assessment of a pilot project in Bolivia. Int’l J. Environ. Health Res. (in press)

““The encouraging results The encouraging results from studies of improved from studies of improved household water household water management provide a management provide a sufficient impetus for resufficient impetus for re--examining the potential examining the potential health impact of health impact of interventions to improve interventions to improve drinking water quality. . . . drinking water quality. . . . This type of analysis should This type of analysis should ultimately help refine the ultimately help refine the dominant paradigm, and dominant paradigm, and lead to more focused lead to more focused guidance on the potential guidance on the potential health impact of water health impact of water quality interventions.”quality interventions.”

Clasen T & Cairncross S (2004). Household water management: refining the dominant paradigm. Trop. Med. Int’l Health 9(2):1-5

Protocol for a Cochrane Review

Clasen T, Roberts I, Rabie T, CairncrossS (2004). Interventions to improve water qualtity for preventing diarrhoea. Cochrane Collaboration, 2004 Issue 2

Interventions at Interventions at SourceSource

Interventions at the Interventions at the HouseholdHousehold

Post Collection Recontamination of WaterPost Collection Recontamination of WaterSystematic review and metaSystematic review and meta--analysis of 57 studies measuring analysis of 57 studies measuring bacteria counts for source water bacteria counts for source water and stored water in the home.and stored water in the home.Results: The bacteriological Results: The bacteriological quality of drinking water quality of drinking water significantly declined after significantly declined after collection in many settings. collection in many settings. Conclusion: Policies that aim to Conclusion: Policies that aim to improve water quality through improve water quality through source improvements may be source improvements may be compromised by postcompromised by post--collection collection contamination. Safer household contamination. Safer household water storage and treatment is water storage and treatment is recommended to prevent this, recommended to prevent this, together with pointtogether with point--ofof--use water use water quality monitoring.quality monitoring.*Wright J, Gundry S, Conroy R (2004). Household drinking water in developing countries: a systematic review of microbiological contamination between source and point-of-use. Tropical Med. Int’l Health9(1): 106-117

Esrey Update: Fewtrell et al.

Fewtrell L, Kaufmann R, Kay D, Enanoria W, Haller L, Colford J (2005). Water, sanitation, and hygiene interventions to reduce diarrhoea in developing countries: a systematic review and meta-analysis. Lancet Infect. Dis 5: 42-52.

No. Studies in ReviewNo. Studies in Review

0

5

10

15

20

25

30

35

40

Esrey 1985* Esrey 1991* Fewtrell 2005* Clasen 2005Review

No.

Stu

dies

Household

Source

*Includes observational studies

Effectiveness: Intervention Type (all age)Effectiveness: Intervention Type (all age)

Effectiveness: Intervention Point (< 5s)Effectiveness: Intervention Point (< 5s)

Summary of EffectivenessSummary of Effectiveness——All agesAll ages

p=0.08p=0.080.58 to 0.820.58 to 0.8231%31%0.690.69Flocc/DisinfFlocc/Disinf (ex (ex DoocyDoocy))

21%21%

52%52%

31%31%

37%37%

63%63%

47%47%

27%27%

% % ∆∆(1(1--RR)RR)

p<0.0001p<0.00010.20 to 1.160.20 to 1.160.480.48Flocc/DisinfFlocc/Disinf (7)(7)

n.an.a..0.61 to 1.030.61 to 1.030.790.79ImprImpr. Storage (1). Storage (1)

p=0.73p=0.730.63 to 0.740.63 to 0.740.690.69Solar Solar DisinfDisinf (2)(2)

p<0.00001p<0.000010.52 to 0.750.52 to 0.750.630.63Chlorination (16)Chlorination (16)

p=0.56p=0.560.28 to 0.490.28 to 0.490.370.37Filtration (6)Filtration (6)

p<0.00001p<0.000010.39 to 0.730.39 to 0.730.530.53Household (32)Household (32)

p<0.00001p<0.000010.53 to 1.010.53 to 1.010.730.73Source (6)Source (6)

Heterogeneity*Heterogeneity*(Chi(Chi--square)square)

95% CI of 95% CI of EstimateEstimate

EstimateEstimate(random)(random)

Intervention Type Intervention Type (no. trials)(no. trials)

*Note that in a test for heterogeneity, a low p-value (eg <0.10) suggests an actual underlying difference in effect between studies that is unlikely to be attributable to chance.

Summary of EffectivenessSummary of Effectiveness——Under 5sUnder 5s

p=.007p=.0070.71 to 1.020.71 to 1.0215%15%0.850.85Source (4)Source (4)

p=0.37p=0.370.24 to 0.530.24 to 0.5364%64%0.360.36Filtration (5)Filtration (5)

p=0.004p=0.0040.67 to 0.860.67 to 0.8624%24%0.760.76Chlorination (12)Chlorination (12)

nanananananananaSolar Solar DisinfecDisinfec (0)(0)

p<0.00001p<0.000010.20 to 1.370.20 to 1.3748%48%0.520.52Flocc/DisinfFlocc/Disinf (7)(7)

p=0.10p=0.100.61 to 0.840.61 to 0.8429%29%0.710.71Flocc/DisinfFlocc/Disinf (6) ((6) (ex ex DoocyDoocy))

p<0.00001p<0.000010.39 to 0.810.39 to 0.8144%44%0.560.56Household (25)Household (25)

31%31%

% % ∆∆(1(1--RR)RR)

n.an.a..0.47 to 0.810.47 to 0.810.690.69ImprImpr. Storage (1). Storage (1)

HeterogeneityHeterogeneity(Chi(Chi--square)square)

95% CI of 95% CI of EstimateEstimate

EstimateEstimate(random)(random)

Intervention Type Intervention Type (no. trials)(no. trials)

CartagenitaCartagenita

DabeibaDabeiba

Oxfam PilotOxfam Pilot----ColombiaColombia•Six-month (March-September 2004) randomized controlled trial of a pilot program using locally-fabricated ceramic water filter using Katadyn® candles

•Following a baseline survey to confirm no differences between persons in intervention (n=415) and control (n=265) groups, filters were randomly allocated to half of the households (n=130) in each of three communities

•Follow-up at monthly intervals to assess water quality and diarrhoea prevalence

Mean Mean ThermotolerantThermotolerant ((FaecalFaecal) ) ColiformColiform (and 95% CI) per 100ml(and 95% CI) per 100ml

<0.0001<0.000137 (26, 48)37 (26, 48)151 (135, 166)151 (135, 166)OverallOverall

<0.0001<0.00010072 (61, 83)72 (61, 83)CartagenitaCartagenita

<0.0001<0.000146 (27, 65)46 (27, 65)220 (193, 247)220 (193, 247)DabeibaDabeiba

<0.0001<0.000150 (30, 71)50 (30, 71)154 (124, 185)154 (124, 185)CurvaradoCurvarado

PP--valuevalueInterventionInterventionControl Control SiteSite

Filters reduced the level of faecal bacteria at all sites, with an overall reduction in arithmetic mean TTC/100ml of 75.3%. However, only in Cartagenita did the filters eliminate all TTC in product water.

Microbiological PerformanceMicrobiological PerformanceOxfamOxfam----ColombiaColombia

47.7% and 24.2% of the samples from the intervention group had no detectible TTC/100ml or conformed to WHO limits for “low risk” (1--10 TTC/100ml), respectively, compared to just 0.9% and 7.3% for control group samples.

0.86%

7.30%

37.34%

54.51%

47.66%

24.22%

17.58%

10.55%

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

0 TTC/100ml 1-10 TTC/100ml 11-100 TTC/100ml 101/1000 TTC/100ml

TTC Count

Per

cent

age

of S

ampl

es

Control Intervention

Health ImpactHealth Impact

0.0050.0050.21, 0.760.21, 0.760.400.40<0.001<0.0010.25, 0.630.25, 0.630.400.40OverallOverall

0.0040.0040.06, 0.580.06, 0.580.190.19<0.001<0.0010.10, 0.410.10, 0.410.210.21CartagenitaCartagenita

0.2970.2970.24, 1.560.24, 1.560.600.600.0950.0950.21, 1.130.21, 1.130.490.49DabeidaDabeida

0.7430.7430.21, 8.870.21, 8.871.371.370.7810.7810.31, 2.390.31, 2.390.870.87CurvaradoCurvarado

P-value95% CIORP-value95% CIORSite

Children < 5 years of ageAll ages

Overall, prevalence of diarrhoea was 60% less among households using filters than control households (OR = 0.40, 95% CI = 0.25,0.63, P < 0.0001). However, the microbiological performance andprotective effect of the filters was not uniform throughout the study communities, and corresponded with microbial performance.

Clasen T, Garcia Parra G, Boisson S, Collin S. Household-based ceramic water filters for the prevention of diarrhoea: a randomized, controlled trial of a pilot program in Colombia. Am J Trop Med Hyg. 73(4):790-95

Summary and ConclusionsSummary and ConclusionsInterventions to improve water quality are effective in Interventions to improve water quality are effective in preventing preventing diarrhoealdiarrhoeal disease, a major killer of children disease, a major killer of children under 5 years of ageunder 5 years of ageInterventions at the household level are about twice as Interventions at the household level are about twice as effective as those at the sourceeffective as those at the sourceEffectiveness was conditioned upon sufficient water Effectiveness was conditioned upon sufficient water quantity, and increased with compliance and improved quantity, and increased with compliance and improved sanitation sanitation In a pilot program in Colombia by Oxfam GB, the filters In a pilot program in Colombia by Oxfam GB, the filters were associated with a 75.3% reduction in the mean were associated with a 75.3% reduction in the mean faecalfaecal bacteria in drinking water and a 60% reduction in bacteria in drinking water and a 60% reduction in diarrhoeadiarrhoeaVariation in results by setting suggests that actual Variation in results by setting suggests that actual effectiveness may depend on local conditions (exposure effectiveness may depend on local conditions (exposure to other sources of transmission) and programmatic to other sources of transmission) and programmatic support to ensure compliancesupport to ensure compliance

Interventions to Improve Water Interventions to Improve Water Quality for the Prevention of Quality for the Prevention of

Diarrhoeal Disease: Diarrhoeal Disease: A CostA Cost--Effectiveness AnalysisEffectiveness Analysis

Thomas Clasen, Damian Walker, Thomas Clasen, Damian Walker, Laurence Haller & Sandy Laurence Haller & Sandy CairncrossCairncross

Interventions to Improve Water Interventions to Improve Water Quality for the Prevention of Quality for the Prevention of

Diarrhoeal Disease: Diarrhoeal Disease: A CostA Cost--Effectiveness AnalysisEffectiveness Analysis

Thomas Clasen, Damian Walker, Thomas Clasen, Damian Walker, Laurence Haller & Sandy Laurence Haller & Sandy CairncrossCairncross

OutlineOutline

Description of water quality interventions in Description of water quality interventions in preventing diarrhoeapreventing diarrhoea

source and household interventionssource and household interventions

Overview of methodsOverview of methodsEstimates of costEstimates of costEstimates of effectiveness and Estimates of effectiveness and DALYsDALYs avertedavertedCE resultsCE resultsLimitations and QualificationsLimitations and Qualifications

Overview of methodsOverview of methods

WHO Generalized CEAWHO Generalized CEAInterventions: 3 source and 4 household approaches to Interventions: 3 source and 4 household approaches to improving microbial quality of drinking water improving microbial quality of drinking water Cost data: WHO data and generic cost protocol sent to Cost data: WHO data and generic cost protocol sent to 12 12 programmeprogramme implementersimplementersEffectiveness data: Cochrane Review Effectiveness data: Cochrane Review Population model: WHO PopModPopulation model: WHO PopModSummary measure: $ per DALY averted for 11 WHO Summary measure: $ per DALY averted for 11 WHO epidemiological subepidemiological sub--regionsregions

today, results for today, results for AfrAfr--E and SearE and Sear--DD

WHO epidemiological subWHO epidemiological sub--regionsregions

Malawi Mozambique Malawi Mozambique Namibia Namibia Rwanda Rwanda

South Africa South Africa Swaziland Swaziland Uganda Uganda

United Republic of United Republic of Tanzania Tanzania Zambia Zambia

Zimbabwe Zimbabwe

Bangladesh Bangladesh Bhutan Bhutan

Democratic People’s Democratic People’s Republic of Korea Republic of Korea

India India Maldives Maldives Myanmar Myanmar

Nepal Nepal

Botswana Botswana Burundi Burundi

Central African Central African Republic Republic Congo Congo

Côte d'Ivoire Côte d'Ivoire Democratic Republic Democratic Republic

of Congo of Congo Eritrea Eritrea

Ethiopia Ethiopia Kenya Kenya

Lesotho Lesotho

SearSear--DDAfrAfr--EE

Estimating CostsEstimating Costs

US$ per person covered per year estimatedUS$ per person covered per year estimatedFor each intervention, a mean and range of costs For each intervention, a mean and range of costs were computedwere computedAssumed linear cost of scaling up to 100% Assumed linear cost of scaling up to 100% coverage (minimal fixed costs)coverage (minimal fixed costs)

Sources for Cost DataSources for Cost Data

Source (regional mean cost of communal Source (regional mean cost of communal tapstandtapstand, , borehole and dug well based on WHO data)borehole and dug well based on WHO data)HouseholdHousehold

chlorination (estimates from 17 country programmes)chlorination (estimates from 17 country programmes)filtration (estimates from Cambodia and Bolivia programmes)filtration (estimates from Cambodia and Bolivia programmes)solar disinfection (estimates from 7 country programmes)solar disinfection (estimates from 7 country programmes)flocculation / disinfection (estimates from 5 country flocculation / disinfection (estimates from 5 country programmes) programmes)

Summary of Cost EstimatesSummary of Cost Estimates

$0.66

$1.88

$2.61

$3.60

$3.03

$0.63

$4.95

$-

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

Source-Africa Source-Asia Source-LA&C Chlorination CeramicFiltration

SolarDisinfection

Flocculation-Disinfection

System

Cos

tMean annual cost per person in US$ of source and household Interventions

(error bars represent range of costs)

DALYs AvertedDALYs AvertedYearly DALYs averted from implementation of water quality interventions to

prevent diarrhoea at 100% coverage level

0

20

40

60

80

100

120

Afr-E Sear-D

WHO Epidemiological Sub Region

Year

ly D

ALY

s Av

erte

d (m

illio

ns)

ChlorinationCeramic FiltrationSolar DisinfectionFlocculation DisinfectionSource

CE plane for CE plane for AfrAfr--EE

CE plane for SearCE plane for Sear--DD

Interpreting Interpreting ICERsICERs

Assumes all the household interventions are mutually Assumes all the household interventions are mutually exclusive, i.e. if one is chosen another cannot beexclusive, i.e. if one is chosen another cannot beFlocculation / disinfection was (strongly) dominated by Flocculation / disinfection was (strongly) dominated by the three other household interventions (solar the three other household interventions (solar disinfection, chlorination and filtration) in both regions, disinfection, chlorination and filtration) in both regions, i.e. they were all more effective i.e. they were all more effective andand less costlyless costlySolar disinfection was (weakly) dominated by Solar disinfection was (weakly) dominated by chlorination in both regions, but this assumes it is chlorination in both regions, but this assumes it is possible to deliver chlorination to less people without possible to deliver chlorination to less people without any change in CEany change in CE

Interpreting CE dataInterpreting CE data

Following the recommendation of the CMH, Following the recommendation of the CMH, WHO uses the following categories:WHO uses the following categories:

$ per DALY averted < GNI per capita = highly CE$ per DALY averted < GNI per capita = highly CE$ per DALY averted 1$ per DALY averted 1--3 * GNI per capita = CE3 * GNI per capita = CE$ per DALY averted > 3* GNI per capita = not CE$ per DALY averted > 3* GNI per capita = not CE

AfrAfr--E GNI per capita: $369E GNI per capita: $369SearSear--D GNI per capita: $276D GNI per capita: $276

Data suggest interventions to improve water Data suggest interventions to improve water quality are:quality are:

highly CE in highly CE in AfrAfr--E and SearE and Sear--DD

AcknowledgementsAcknowledgements

CDC (S. CDC (S. LubyLuby, R. Quick J. Crump, T. Chiller, E. , R. Quick J. Crump, T. Chiller, E. MintzMintz))Proctor & Gamble (G. Proctor & Gamble (G. AllgoodAllgood, B. Keswick), B. Keswick)WHO (J. Bartram, B. Gordon, L. Haller)WHO (J. Bartram, B. Gordon, L. Haller)UC Berkeley (J. UC Berkeley (J. ColfordColford))University of Wales (L. University of Wales (L. FewtrellFewtrell))Colleagues at LSHTM (V. Curtis, I. Roberts, T. Colleagues at LSHTM (V. Curtis, I. Roberts, T. RabieRabie, L. Smith, W. Schmidt, S. Thomas), L. Smith, W. Schmidt, S. Thomas)

AcknowledgementsAcknowledgementsOxfam GB Colombia (G. Garcia Oxfam GB Colombia (G. Garcia ParraParra, F. Vidal, LM , F. Vidal, LM LondonaoLondonao, T. Forster, A , T. Forster, A BastableBastable) ) CDC (S. CDC (S. LubyLuby, R. Quick J. Crump, T. Chiller, E. , R. Quick J. Crump, T. Chiller, E. MintzMintz))Proctor & Gamble (G. Proctor & Gamble (G. AllgoodAllgood, B. Keswick), B. Keswick)WHO (J. WHO (J. BartramBartram, B. Gordon, L. Haller), B. Gordon, L. Haller)Johns Hopkins University (S. Johns Hopkins University (S. DoocyDoocy))University of Bristol (S. Gundry, J. Wright)University of Bristol (S. Gundry, J. Wright)UC Berkeley (J. UC Berkeley (J. ColfordColford))University of Wales (L. University of Wales (L. FewtrellFewtrell))University of North Carolina (M. University of North Carolina (M. SobseySobsey, J. Brown), J. Brown)Colleagues at LSHTM (S. Colleagues at LSHTM (S. CairncrossCairncross, V. Curtis, I. , V. Curtis, I. Roberts, T. Roberts, T. RabieRabie, L. Smith, W. Schmidt, S. Thomas), L. Smith, W. Schmidt, S. Thomas)