the mapsan trial: a controlled before‐and‐after (cba) study of shared sanitation in maputo,...
TRANSCRIPT
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The MapSan Trial A controlled before‐and‐after (CBA) study of shared sanitation in Maputo, Mozambique
Joe Brown (GT)Oliver Cumming (LSHTM)
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LSHTM
Oliver Cumming Olimpio ZavaleWolf Schmidt
Sandy Cairncross
GT
Joe Brown (PI)Jackie Knee
Other students
UNC
Pete KolskyJamie BartramJill Stewart
David Holcomb
UFL
Song LiangRick Rheingans
WSUP
Guy Norman Carla Costa
Vasco Parente
World Bank WSPPeter Hawkins
USAIDURC
TRAction
The team:
• Study Management• Research• Intervention
MISAU
Dr Rassul Nala
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Do we really need another sanitation trial?
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Recent sanitation trials
• Alzua et al 2015• Patil et al 2014• Clasen et al 2014• Hammer & Spears 2013• Cameron et al 2012
What have these trials taught us?• It is very hard to convince people people in rural settings to invest in and use sanitation• Wide variation in measured health effects between studies• Communicate findings carefully
What have these trials not addressed?• High density informal settlements• Urban onsite sanitation with facilities shared by multiple households• Enteric infections linked to specific transmission pathways• Enteric infections linked to anthropometric outcomes
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Primary study questions
1. Can urban, on‐site, shared sanitation reduce risk of enteric infections in children?
2. Do enteric infection risks and the effects of urban sanitation vary by localized population density?
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Study rationaleCurrently…•Progress on urban sanitation slow in sub‐Saharan Africa•Low priority sometimes afforded to urban (onsite) sanitation•Costs sometimes perceived as prohibitive•Perceived absence of safe, viable and cost‐effective interventions for slums•Lack of evidence for the effects of onsite urban sanitation interventions
Questions from policy and practice community•Is sanitation more important in high density settings•Uncertainty around the benefits •Uncertainty around the benefits for shared sanitation•Does “shared sanitation” count as “improved sanitation” ?
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Is it plausible that sanitation‐related disease transmission varies by population density?
Higher concentration of environmental contamination – more feces, less space
Higher risk of exposure – environmental pathways and person‐to‐person
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”It is… a well‐known fact that the evil effects of an increased aggregation of population are much more apparent during the early years of life”
SOURCE: Williamson (1911)
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Intervention: urban, shared private sanitation by WSUP
12‐20 people (3‐5 HHs)
20 – 100+ people
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Study designControlled before‐and‐after (CBA)
Children after new sanitation
Children before new sanitation
Children with existing shared sanitation
Children with same shared sanitation
∆
∆
12 months
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Study design• Controlled before‐and‐after (CBA)
– Why not an RCT?• Not possible to randomize• Demand and use
• 380 children with new‐and‐improved shared sanitation, 380 controls with existing shared sanitation
• Allocation according to WSUP formula for siting, matched on site criteria, time of enrollment, size
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Before
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After
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Site selection: intervention• (1) sites within the pre‐defined project geographical scope;• (2) residents must be currently using shared sanitation in poor
condition, based on inspection by WSUP engineers; • (3) sites must meet WSUP criteria for a minimum number of
beneficiaries (15 for shared latrines, 25 for CSBs); • (4) sites must have a legal piped water connection nearby for
possible use with pour‐flush latrines; • (5) residents must convey stated demand for improved sanitation
and have a stated interest in contributing to cost: 10% total cost of the communal sanitation blocks or 15% of the cost of shared latrines, divided by the beneficiary households and over 12 months following the start of construction;
• (6) sites must have available space to implement the new facility (often replacing the space occupied by existing shared facilities);
• (7) sites must be accessible for transport of materials during construction and to allow for later tank emptying.
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Control selection
• Come from a similar site that will not receive a shared latrine – Cluster of households that share a latrine in poor condition, with 15+ people, at least 1 child
• Some will be in the 11 JSDF bairros, some in other nearby bairros that are similar
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Site selection: control• (1) sites within the pre‐defined project geographical scope;• (2) residents must be currently using shared sanitation in poor
condition, based on inspection by WSUP engineers; • (3) sites must meet WSUP criteria for a minimum number of
beneficiaries (15 for shared latrines, 25 for CSBs); • (4) sites must have a legal piped water connection nearby for
possible use with pour‐flush latrines; • (5) residents must convey stated demand for improved sanitation
and have a stated interest in contributing to cost: 10% total cost of the communal sanitation blocks or 15% of the cost of shared latrines, divided by the beneficiary households and over 12 months following the start of construction;
• (6) sites must have available space to implement the new facility (often replacing the space occupied by existing shared facilities);
• (7) sites must be accessible for transport of materials during construction and to allow for later tank emptying.
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What we’re measuring
Compliance Intermediary outcomes OutcomesFidelity
Covariates
Stratification variables
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Measuring density
(1) Number of total people/children under 5 within 50 m of the center of a given household, measured in a direct line, with all members of any household touched by the line included ; and
(2) Number of total people/children within 100 m
(3) Number of people/children under 5 within the shared space as defined by a household cluster (common area shared by households sharing the latrine)
Median, tertiles, quintiles
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Shared space/compound density• Planimeter ‐ GPS Area Measure v 1.0.0 by Vistech
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Visit 1: before hand over• Area of household and common areas measured for density calculation
• Observational data • Informed consent• Age and weight of all children• Saliva samples• Brief household survey for all households with children• Leave stool sample containers• Leave fly traps• Make arrangements with household to come back next day
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Visit 2: next day
• Collection of stool samples to take to MISAU. • Drinking water samples• Soil samples• Collect fly samples
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Visit 3: point of handover• De‐worming: each child over 12 months• Single‐dose albendazole (a broad spectrum de‐worming treatment) will be offered to everyone in intervention and control households (and their entire compounds)
• Exceptions: pregnant women in first trimester and children under 12 months.
• Ministry of Health (MISAU) staff, working within the National Deworming Campaign (NDC), will administer albendazole in accordance with MISAU standard safety protocols and dosage guidelines.
• Current dosing guidelines are to administer 400 mg for all ages (except for children between 12 and 24 months, who receive 200 mg in a suspension).
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Visit 4: one year later
• Observational data • Age and weight of all children• Saliva samples• Brief household survey for all households with children
• Leave a stool sample container• Leave fly traps• Make arrangements with household to come back next day
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Visit 5: next day
• Collection of stool samples to take to MISAU. • Drinking water samples• Soil samples• Collect fly samples• De‐worming: each child over 12 months (albendazole)
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Outcome measures• Primary outcome
– Combined prevalence of non‐STH enteric infections in children under 5
– Enteric infections: STH, Campylobacter, C. difficile, Toxin A/B, ETEC LT/ST, STEC; Salmonella, Shigella, V. cholerae, Y enterocolitica, adenovirus GI/GII, RV A, Giardia, Cryptosporidium, E. histolytica
• Secondary outcomes – 1. Combined prevalence of STHs in children under 5 (re‐infection): Ascaris lumbricoides, Trichuris trichiura, hookworm, Enterobius vermiculare, Taenia spp., Hymenolepis spp., and Strongyloides stercoralis
– 2. Reported diarrhea, 7 day recall (self‐report)
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Outcome measures, continued
• Tertiary outcome measures– Measures of environmental enteric dysfunction (EED)
• Myeloperoxidase, alpha‐anti‐trypsin, neopterin
– All‐cause mortality– Anthropometry
• WAZ, LAZ, WHZ
– Salivary IGF‐1
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Environmental metrics• Household water samples, as an indicator of household hygiene
• Soil samples • Fly samples • A subset of samples will be tested for Bacteroides, E. coli, Enterococci, and pathogens
• Sanitary surveys
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Water
Enteric infections
Food
Hands
Flies
Soil & surfaces
Enteric infections
SANITATION
WATER QUALITY
HAND WASHINGWATER QUANTITY
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Extensions• SaniPath partnership on environmental metrics
• Rotavirus vaccine blunting nested cohort study
• Long‐term child growth cohort
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Thank [email protected]
ACKNOWLEDGEMENTS
COLLABORATING PARTNERSGeorgia Institute of TechnologyLondon School of Hygiene and Tropical MedicineMinisterio da Saude de MoçambiqueUniversity of FloridaUniversity of North CarolinaWater and Sanitation for the Urban PoorWorld Bank Water and Sanitation Programme
FUNDING & DISCLAIMERThis study was funded by the United States Agency for International Development under Translating Research into Action, Cooperative Agreement No. GHS‐A‐00‐09‐00015‐00.
This study is made possible by the support of the American People through the Unites States Agency for International Development (USAID). The findings of this study are the sole responsibility of LSHTM and Georgia Tech and do not necessarily reflect the views of USAID or the United States Government.
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Questions• 1. Is it plausible to expect that onsite shared sanitation is likely to result in lower exposure to pathogens among children in these settings?– Do these septic tanks work? Where is the leach field?
• 2. Isn’t density likely co‐linear with poverty? So how will we sort this out?
• 3. What about child feces disposal? The intervention may not affect this.
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More questions• 4. Are the controls suitable? Are we selecting for factors that may be related to exposures or outcomes?
• 5. What if the primary outcome variable (and STHs) are unaffected by the intervention?– Particularly viruses?– Poor effectiveness of single‐dose albendazole
• 6. How strongly associated are outcome measures and population density? – Will use baseline analysis
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MapSan• The first controlled health impact trial of an urban de‐centralized (non‐sewerage) sanitation intervention.– Most common form of sanitation in urban areas
• The first sanitation health impact trial of shared sanitation (760m+ users, mostly in SSA).
• The first sanitation health impact trial that uses a direct measure of enteric infections as a primary outcome measure. – On causal chain for ALL downstream impacts, objective
• The first sanitation health impact trial that includes a focus on localized population density.