Household water treatment (HWTS) methods, such as boiling or chlorination, have long been recommended in emergencies. While there is increasing evidence of HWTS efficacy in the development context, effectiveness in the acute emergency context has not been rigorously assessed. We investigated HWTS effectiveness in response to four acute emergencies by surveying 1521 targeted households and testing stored water for free chlorine residual and fecal indicators. We defined "effective use" as the percentage of the targeted population with contaminated household water who used the HWTS method to improve stored drinking water microbiological quality to internationally accepted levels. Chlorine-based methods were distributed in all four emergencies and filters in one emergency. Effective use ranged widely, from 0-67.5%, with only one pre-existing chlorine program in Haiti and unpromoted boiling use in Indonesia reaching >20%. More successful programs provided an effective HWTS method, with the necessary supplies and training provided, to households with contaminated water who were familiar with the method before the emergency. HWTS can be effective at reducing the risk of unsafe drinking water in the acute emergency context. Additionally, by focusing on whether interventions actually improve drinking water quality in vulnerable households, "effective use" provides an important program evaluation metric.
Locally produced ceramic pot filters have been shown to improve the microbiological quality of household drinking water and reduce the burden of diarrheal disease in users. They are considered one of the most promising household water treatment methods. However, overarching manufacturing and quality control guidelines do not exist for the 35 decentralized filter factories in 18 countries that currently produce filters. In this study, we conducted manufacturing process surveys with 25 filter factories worldwide to document production methods and identify areas where manufacturing and quality control guidelines are needed. Our results show that manufacturing processes vary widely both between and within factories, including the consistency of materials, manufacturing methods, and quality control practices. These variations pose concerns about the consistency and quality of locally produced filters in the absence of standardized quality control procedures. We propose areas where manufacturing guidelines are needed to assist factories in producing consistently high quality filters, and identify topics where further research is needed to refine manufacturing recommendations. These results guided the development of a best practice manual that described consensus-based recommendations to advance consistent, quality-controlled filter production world-wide.
BackgroundLarge epidemics frequently emerge in conflict-affected states. We examined the cholera response during the humanitarian crisis in Yemen to inform control strategies.MethodsWe conducted interviews with practitioners and advisors on preparedness; surveillance; laboratory; case management; malnutrition; water, sanitation and hygiene (WASH); vaccination; coordination and insecurity. We undertook a literature review of global and Yemen-specific cholera guidance, examined surveillance data from the first and second waves (28 September 2016–12 March 2018) and reviewed reports on airstrikes on water systems and health facilities (April 2015–December 2017). We used the Global Task Force on Cholera Control’s framework to examine intervention strategies and thematic analysis to understand decision making.ResultsYemen is water scarce, and repeated airstrikes damaged water systems, risking widespread infection. Since a cholera preparedness and response plan was absent, on detection, the humanitarian cluster system rapidly developed response plans. The initial plans did not prioritise key actions including community-directed WASH to reduce transmission, epidemiological analysis and laboratory monitoring. Coordination was not harmonised across the crisis-focused clusters and epidemic-focused incident management system. The health strategy was crisis focused and was centralised on functional health facilities, underemphasising less accessible areas. As vaccination was not incorporated into preparedness, consensus on its use remained slow. At the second wave peak, key actions including data management, community-directed WASH and oral rehydration and vaccination were scaled-up.ConclusionDespite endemicity and conflict, Yemen was not prepared for the epidemic. To contain outbreaks, conflict-affected states, humanitarian agencies, and donors must emphasise preparedness planning and community-directed responses.
To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94–3.01 log reduction in E. coli concentration without, and 2.18–3.34 with, soil load; and a 2.44–3.06 log reduction in Phi6 without, and 2.71–3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28–4.77 log reduction in remaining E. coli without, and 0.21–4.49 with, soil load and a 1.26–2.02 log reduction in Phi6 without, and 1.30–2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001). Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence.
Locally produced ceramic water filters (CWF) are an effective technology to treat pathogen-contaminated drinking water at the household level. CWF manufacturers apply silver to filters during production, although the silver type and concentration vary and evidence-based silver application guidelines have not been established. We evaluated the effects of three concentrations of two silver species on effluent silver concentration, E. coli removal, and viable bacteria retained on the surface and contained in the pores of ceramic disks manufactured with clay imported from three CWF factories using sawdust as the burn-out material. Additionally, we evaluated performance using water with three chemistry characteristics (Na+–NaCl, Ca2+–CaCl2, and humic acid as natural organic matter) of disks made from the different clays using either sawdust or rice husk as the burn-out material. Results showed the following: (1) Silver desorption from disks coated with silver nitrate (Ag+) was greater than desorption of silver nanoparticles (nAg) for all disks. (2) Effluent silver concentration, E. coli removal, and viable bacteria retention were dose-dependent on the amount of silver applied. (3) Nither water chemistry conditions (inorganic or organic compounds) nor burn-out material showed an effect on any of the parameters evaluated at the silver concentration tested. The recommendation for filter manufacturers to use only nAg and at a higher concentration than currently recommended is discussed.
We conducted a systematic review of hygiene intervention effectiveness against SARS-CoV-2, including developing inclusion criteria, conducting the search, selecting articles for inclusion, and summarizing included articles. Overall, 96 268 articles were screened and 78 articles met inclusion criteria with outcomes in surface contamination, stability, and disinfection. Surface contamination was assessed on 3343 surfaces using presence/absence methods. Laboratories had the highest percent positive surfaces (21%, n = 83), followed by patient-room healthcare facility surfaces (17%, n = 1170), non-COVID-patient-room healthcare facility surfaces (12%, n = 1429), and household surfaces (3%, n = 161). Surface stability was assessed using infectivity, SARS-CoV-2 survived on stainless steel, plastic, and nitrile for half-life 2.3–17.9 h. Half-life decreased with temperature and humidity increases, and was unvaried by surface type. Ten surface disinfection tests with SARS-CoV-2, and 15 tests with surrogates, indicated sunlight, ultraviolet light, ethanol, hydrogen peroxide, and hypochlorite attain 99.9% reduction. Overall there was (1) an inability to align SARS-CoV-2 contaminated surfaces with survivability data and effective surface disinfection methods for these surfaces; (2) a knowledge gap on fomite contribution to SARS-COV-2 transmission; (3) a need for testing method standardization to ensure data comparability; and (4) a need for research on hygiene interventions besides surfaces, particularly handwashing, to continue developing recommendations for interrupting SARS-CoV-2 transmission.
The 2014 West African Ebola virus disease outbreak was the largest to date, and conflicting, chlorine-based surface disinfection protocols to interrupt disease transmission were recommended. We identified only one study documenting surface disinfection efficacy against the Ebola virus, showing a >6.6 log reduction after 5-minute exposure to 0.5% sodium hypochlorite (NaOCl) based on small-scale tests (Cook et al. (2015)). In preparation for future extensive, large-scale disinfection efficacy experiments, we replicated the Cook et al. experiment using four potential BSL-1 surrogates selected based on similarities to the Ebola virus: bacteriophages MS2, M13, Phi6, and PR772. Each bacteriophage was exposed to 0.1% and 0.5% NaOCl for 1, 5, and 10 minutes on stainless steel. MS2 and M13 were only reduced by 3.4 log and 3.5 log after a 10-minute exposure to 0.5% NaOCl, and would be overly conservative surrogates. Conversely, PR772 was too easily inactivated for surrogate use, as it was reduced by >4.8 log after only 1-minute exposure to 0.5% NaOCl. Phi6 was slightly more resistant than the Ebola virus, with 4.1 log reduction after a 5-minute exposure and not detected after a 10-minute exposure to 0.5% NaOCl. We therefore recommend Phi6 as a surrogate for evaluating the efficacy of chlorine-based surface disinfectants against the Ebola virus.
Point‐of‐use (POU) water treatment with sodium hypochlorite (NaOCl) has been proven to reduce diarrheal disease in developing countries. However, program implementation is complicated by unclear free chlorine residual guidelines for POU water treatment and difficulties in determining appropriate dosage recommendations. The author presents evidence supporting proposed criteria for household water treatment for free chlorine residuals of < 2.0 mg/L 1 h after NaOCl addition and > 0.2 mg/L after 24 h of storage. In testing of 106 drinking water sources from 13 countries, free chlorine residual was measured for 24 h after treatment with different NaOCl doses. For most unchlorinated water (with turbidity < 10 ntu or from an improved source), the NaOCl dose necessary to meet the proposed criteria was 1.875 mg/L. For most unimproved sources with turbidity of 10‐100 ntu, the required dose was 3.75 mg/L. POU chlorination is not recommended in waters with turbidity > 100 ntu. The article also discusses the applicability of POU water treatment with NaOCl to emergency water treatment.
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