Health Impact of Treating and Safely Storing Shallow Tubewell Drinking Water
Condition: Diarrhoeal Disease
Study type: Interventional

Summary: 
      When shallow tubewells replaced highly contaminated surface water as the primary source of
      drinking water in Bangladesh in the late 20th century, contemporary studies demonstrated no
      reduction in diarrheal disease with this improvement in water source. This lack of
      improvement in transitioning to tubewells is consistent with the lack of significant health
      gains observed in intervention studies focusing on water quality improvements at the source.
      In contrast, high quality intervention studies that improve water quality at the point of use
      through treatment of water in households show a 39% reduction in diarrhea.

      The primary objective of this study is within a typical setting in rural Bangladesh where
      households use shallow tubewell water for drinking. The investigators will randomly assign
      1800 households who have a child between the ages of six months and two years to one of three
      groups. Group 1 will receive a safe water storage vessel with a lid and a narrow mouth/tap
      and Aquatabs, an effervescent water purification tablet that utilizes sodium
      dichloroisocyanurate (NaDCC) as the chlorine donor. Group 2 will only receive a safe water
      storage vessel with a lid and a narrow mouth/tap. Group 3 will receive no water intervention
      and continue their standard habits and practices. Every month a field research assistant will
      visit each participating household and collect information on the prevalence of diarrhea
      among children between the ages of six months and two years, as well as children between the
      ages of two and five years if present in the household. Diarrhea prevalence in the 48 hours
      and 7 days preceding the visit will be recorded. The investigators will compare the
      longitudinal prevalence of diarrhea between the following groups: (1) households that receive
      chlorine and storage container versus households that only receive storage container to
      assess the effect of chlorination, (2) households that only receive storage container versus
      households that receive no intervention to assess the effect of safe storage, and (3)
      households that receive chlorine and storage container versus households that receive no
      intervention to assess the combined effect of chlorination and safe storage.

      Hypothesis:

      Drinking water from shallow tubewells that are intermittently contaminated with enteric
      pathogens contributes importantly to diarrhea among children in rural Bangladesh.
    

Detailed description: 
      Setting: The investigators will conduct the study in the Fulbaria upazila of Mymensingh
      district, where groundwater chemistry has been proven to be amenable to disinfection with
      chlorine. Groundwater in many areas in Bangladesh is rich in iron and other ions that react
      with chlorine and limit its capacity to provide adequate disinfection. Groundwater testing in
      Fulbaria has shown that chlorination works effectively at this location, as discussed below.

      Develop Intervention: This is an efficacy study, i.e. it is trying to answer the question: if
      tubewell water were effectively chlorinated and/or safely stored in homes, what would be the
      impact on childhood diarrhea. To efficiently answer this question, the investigators will
      strive to optimize the use of the intervention in those households randomized to receive the
      intervention. Chlorinating water has been shown to be an effective way of disinfecting water
      in the home (Arnold and Colford, 2007). The investigators will use Aquatabs for chlorination,
      which are effervescent water purification tablets that utilize sodium dichloroisocyanurate
      (NaDCC) as the chlorine donor. NaDCC was judged to be a safe and appropriate treatment for
      water by the World Health Organization (Clasen and Edmondson, 2006) and has been tested and
      found acceptable to a community of urban residents in Dhaka, Bangladesh (Clasen et al.,
      2007a). Aquatabs are also easier to store, handle and correctly dose than liquid forms of
      chlorine (Clasen and Edmondson, 2006).

      Groundwater Testing: To optimize the use of Aquatabs and determine the appropriate dose to be
      assigned to study participants, the investigators collected water samples from 52 shallow
      tubewells geographically spread out over all 13 unions in Fulbaria. Water was collected in 5L
      and 10L jerry cans with a narrow mouth and lid. One Aquatabs tablet was added to each vessel,
      resulting in a free chlorine dose of 2 mg/L in the 10L container and 4 mg/L in the 5L
      container. Remaining chlorine residual in the vessels was measured half an hour and 24 hours
      after the addition of the tablet to assess whether it meets the target criteria of having a
      minimum residual of 0.2 mg/L at 24 hours (to ensure adequate disinfection) and a maximum
      residual of 2 mg/L at half an hour (to minimize taste and odor concerns). It should be noted
      that the 2 mg/L taste/odor threshold the investigators are targeting is well under the WHO
      health limit of 5 mg/L. Based on the testing results, the investigators determined that using
      one Aquatabs with a 10L jerry can provides the optimal chlorine dose in Fulbaria.

      Intervention Groups: The study will have the following three arms, which will allow us to
      establish the respective roles of household water treatment and safe water storage in
      preventing diarrheal illness in children in the rural Bangladesh setting.

      Group 1 - Aquatabs and Safe Storage Vessel: Households in this group will receive Aquatabs
      for water purification, a safe water storage container to prevent contamination during
      storage in the home, and training and encouragement to treat and safely store their water
      using the provided products.

      Group 2 - Safe Storage Vessel: Households in this group will receive a safe water storage
      container, and training and encouragement to safely store their water using the provided
      products. If our study shows that treatment of tubewell water at the household level is
      effective in protecting children's health, they will receive a six-month supply of water
      treatment tablets at the end of the study.

      Group 3 - Standard Practices: Households in this group will not receive any water treatment
      or storage intervention during the study. They will continue their usual water collection and
      storage practices. If our study shows that treatment and safe storage of tubewell water at
      the household level is effective in protecting children's health, they will receive the same
      safe water storage container as Groups 1 and 2 as well as a six-month supply of water
      treatment tablets at the end of the study.

      Selection of Households: Households to participate in the study will be recruited through a
      systematic sample from a subset of villages in Fulbaria selected based on field factors such
      as ease of transport and proximity to the field office. The inclusion criteria will include
      (1) using a shallow tubewell that is free from iron complaints as the bari's primary source
      of drinking water and (2) having a child between the ages of six months and two years living
      in the bari. The primary caregiver in the household that has the child in the target range
      will be recruited into the study. If there are multiple households in the bari that have a
      child between the ages of six months and two years, one of the households will be randomly
      selected and the primary caregiver in the selected household will be recruited. Recruited
      households will be randomized into one of the three study arms by block randomization through
      a randomly generated, pre-established sequence that will determine which intervention will be
      allocated to the household.

      Promotion of Interventions: The intervention will continue for five months. At the first
      visit to the households, Groups 1 and 2 will be provided with a plastic water storage
      container with a lid and a narrow mouth/tap, and Group 1 will also be given a one-month
      supply of tablets. Households will be taught through demonstrations and a flipchart with
      illustrations how to use the tablets as well as how to properly use and clean the safe
      storage containers, and they will be encouraged to use them regularly. They will also be
      given an instructions sheet with illustrations that will be left at a visible spot in the
      household and serve as a reminder to clean the containers and if applicable add the water
      treatment tablets. A field research assistant who is not part of the evaluation team will
      visit the household once per month to encourage regular water treatment and safe storage,
      replenish the supply of tablets and address any issues with the maintenance and cleaning of
      the safe storage vessels. The rest of the protocol has been written assuming that households
      will receive monthly promotion visits. However, if the pilot study shows that more frequent,
      intensive promotion leads to significantly better uptake, in the full-scale study the
      investigators will consider replacing the monthly promotion frequency with more frequent
      promotion visits.

      Data Collection: There will be one baseline visit and five follow-up visits to participating
      households.

      Baseline Visit: The investigators will conduct a baseline survey including demographics,
      household description, socioeconomic status, pre-intervention water, sanitation and hygiene
      habits and baseline levels of diarrhea in children between the ages of six months and two
      years. If there are any children in a recruited household that are between the ages of two
      and five, the investigators will collect diarrhea data on them as well to allow comparison of
      our results to other findings in the literature that focus on children under the age of five.
      During the baseline visit, the investigators will assess the microbial quality of the
      tubewell and stored water for each study household using the hydrogen sulphide (H2S) test.
      Tubewell and stored water samples from a subset of 150 households (50 from each study arm)
      will be analyzed for total coliforms and E. coli using membrane filtration.

      Follow-Up Visits: Every month a field research assistant will visit each participating
      household to conduct a follow-up survey and collect information on the prevalence of diarrhea
      among children between the ages of six months and five years in the 48 hours as well as 7
      days preceding the visit. The investigators are using a 48-hour recall because this typically
      provides a more valid estimate than longer recall periods which lead to under-reporting of
      health outcomes (Alam et al., 1989, Ramakrishnan et al., 1999, Feikin et al., 2010). The
      investigators are also using a 7-day recall because recent findings indicate that while this
      longer recall period leads to only minimal bias in terms of the accuracy of recall it can
      result in significant gains of statistical power (Arnold et al., unpublished data). The
      investigators will visit households once every month, because more frequent visits provide
      little additional statistical power due to correlation of repeated measures on the same
      individuals (Schmidt et al., 2007).

      At each visit, the investigators will also collect information on user compliance with the
      interventions by asking about type and timing of water treatment practices, counting the
      number of remaining tablets and inspecting the water storage facilities, as well as asking
      participants when and how they cleaned the storage container. The investigators will also
      collect water samples from the tubewell and storage container in households to assess the
      microbial quality of the water, explore the extent of contamination at the source versus in
      the home and gauge the effectiveness of the interventions in preventing contamination. The
      investigators will perform H2S testing in half of study households and total coliform/E.coli
      testing with membrane filtration for a subset of 150 households (50 from each study arm).
      Moreover, for each household in the Aquatabs group, the investigators will analyze stored
      water samples for residual chlorine concentration to monitor compliance with the
      intervention.

      Laboratory Testing: Water samples will be placed on ice and transported to the Fulbaria field
      office where the appropriate tests will be conducted by the field microbiologists. All
      testing will be performed promptly upon transporting the samples to the field office. The
      hydrogen sulfide (H2S) test is a simple low-cost test (Sobsey and Pfaender, 2003). Twenty ml
      of water will be added in H2S bottle and incubated at room temperature for 24-48 hours. If
      the colour of the water changes to black, it will indicate that the water is contaminated
      with coliform which will indicate that the water is unfit for human consumption. For membrane
      filtration, collected water samples will be quantitatively tested for total coliforms and E.
      coli using the DelAgua kit with MI Broth (Whatman Inc, New Jersey, USA). For residual
      chlorine testing, the investigators will use the n,n-diethyl-p-phenylenediamine (DPD)
      colorimetric method which is part of the DelAgua kit.
    

Intervention name(s): Sodium dichloroisocyanurate (NaDCC) tablet (Aquatab); Water storage container (Jerry can); No intervention
Intervention type(s): Drug; Device; Other
Intervention description(s): One tablet should be added to 10L container, resulting in a free chlorine dose of 2 mg/L.; Shallow tubewell water should be stored in 10L container.
Other intervention name(s): Aquatab; Jerry can
Intervention MeSH terms: Troclosene
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: water; tubewell; diarrhea; chlorination; safe storage