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Casey JA, Daouda M, Babadi RS, Do V, Flores NM, Berzansky I, González DJ, Van Horne YO, James-Todd T. Methods in Public Health Environmental Justice Research: a Scoping Review from 2018 to 2021. Curr Environ Health Rep 2023; 10:312-336. [PMID: 37581863 PMCID: PMC10504232 DOI: 10.1007/s40572-023-00406-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2023] [Indexed: 08/16/2023]
Abstract
PURPOSE OF REVIEW The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods. RECENT FINDINGS We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.
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Affiliation(s)
- Joan A. Casey
- University of Washington School of Public Health, Seattle, WA USA
- Columbia University Mailman School of Public Health, New York, NY USA
| | - Misbath Daouda
- Columbia University Mailman School of Public Health, New York, NY USA
| | - Ryan S. Babadi
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, USA
| | - Vivian Do
- Columbia University Mailman School of Public Health, New York, NY USA
| | - Nina M. Flores
- Columbia University Mailman School of Public Health, New York, NY USA
| | - Isa Berzansky
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, USA
| | - David J.X. González
- Department of Environmental Science, Policy & Management and School of Public Health, University of California, Berkeley, Berkeley, CA 94720 USA
| | | | - Tamarra James-Todd
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, USA
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Colston JM, Hinson P, Nguyen NLH, Chen YT, Badr HS, Kerr GH, Gardner LM, Martin DN, Quispe AM, Schiaffino F, Kosek MN, Zaitchik BF. Effects of hydrometeorological and other factors on SARS-CoV-2 reproduction number in three contiguous countries of tropical Andean South America: a spatiotemporally disaggregated time series analysis. IJID REGIONS 2023; 6:29-41. [PMID: 36437857 PMCID: PMC9675637 DOI: 10.1016/j.ijregi.2022.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 06/09/2023]
Abstract
Background The COVID-19 pandemic has caused societal disruption globally, and South America has been hit harder than other lower-income regions. This study modeled the effects of six weather variables on district-level SARS-CoV-2 reproduction numbers (Rt ) in three contiguous countries of tropical Andean South America (Colombia, Ecuador, and Peru), adjusting for environmental, policy, healthcare infrastructural and other factors. Methods Daily time-series data on SARS-CoV-2 infections were sourced from the health authorities of the three countries at the smallest available administrative level. Rt values were calculated and merged by date and unit ID with variables from a unified COVID-19 dataset and other publicly available sources for May-December, 2020. Generalized additive models were fitted. Findings Relative humidity and solar radiation were inversely associated with SARS-CoV-2 Rt . Days with radiation above 1000 kJ/m2 saw a 1.3% reduction in Rt , and those with humidity above 50% recorded a 0.9% reduction in Rt . Transmission was highest in densely populated districts, and lowest in districts with poor healthcare access and on days with lowest population mobility. Wind speed, temperature, region, aggregate government policy response, and population age structure had little impact. The fully adjusted model explained 4.3% of Rt variance. Interpretation Dry atmospheric conditions of low humidity increase district-level SARS-CoV-2 reproduction numbers, while higher levels of solar radiation decrease district-level SARS-CoV-2 reproduction numbers - effects that are comparable in magnitude to population factors like lockdown compliance. Weather monitoring could be incorporated into disease surveillance and early warning systems in conjunction with more established risk indicators and surveillance measures. Funding NASA's Group on Earth Observations Work Programme (16-GEO16-0047).
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Affiliation(s)
- Josh M. Colston
- Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Patrick Hinson
- College of Arts and Sciences, University of Virginia, VA, USA
| | | | - Yen Ting Chen
- Department of Emergency Medicine, Chi-Mei Medical Center, Tainan, Taiwan
| | - Hamada S. Badr
- Department of Earth and Planetary Sciences, Johns Hopkins Krieger School of Arts and Sciences, Baltimore, MD, 21218, USA
| | - Gaige H. Kerr
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington, DC, USA
| | - Lauren M. Gardner
- Department of Civil and Systems Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - David N. Martin
- Claude Moore Health Sciences Library, University of Virginia School of Medicine, VA, USA
| | | | - Francesca Schiaffino
- Faculty of Veterinary Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
- Division of Infectious Diseases and International Health and Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Margaret N. Kosek
- Division of Infectious Diseases and International Health and Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Benjamin F. Zaitchik
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington, DC, USA
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Capone D, Barker T, Cumming O, Flemister A, Geason R, Kim E, Knee J, Linden Y, Manga M, Meldrum M, Nala R, Smith S, Brown J. Persistent Ascaris Transmission Is Possible in Urban Areas Even Where Sanitation Coverage Is High. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15969-15980. [PMID: 36288473 PMCID: PMC9671051 DOI: 10.1021/acs.est.2c04667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
Abstract
In low-income, urban, informal communities lacking sewerage and solid waste services, onsite sanitation (sludges, aqueous effluent) and child feces are potential sources of human fecal contamination in living environments. Working in informal communities of urban Maputo, Mozambique, we developed a quantitative, stochastic, mass-balance approach to evaluate plausible scenarios of localized contamination that could explain why the soil-transmitted helminth Ascaris remains endemic despite nearly universal coverage of latrines that sequester most fecal wastes. We used microscopy to enumerate presumptively viable Ascaris ova in feces, fecal sludges, and soils from compounds (i.e., household clusters) and then constructed a steady-state mass-balance model to evaluate possible contamination scenarios capable of explaining observed ova counts in soils. Observed Ascaris counts (mean = -0.01 log10 ova per wet gram of soil, sd = 0.71 log10) could be explained by deposits of 1.9 grams per day (10th percentile 0.04 grams, 90th percentile 84 grams) of child feces on average, rare fecal sludge contamination events that transport 17 kg every three years (10th percentile 1.0 kg, 90th percentile 260 kg), or a daily discharge of 2.7 kg aqueous effluent from an onsite system (10th percentile 0.09 kg, 90th percentile 82 kg). Results suggest that even limited intermittent flows of fecal wastes in this setting can result in a steady-state density of Ascaris ova in soils capable of sustaining transmission, given the high prevalence of Ascaris shedding by children (prevalence = 25%; mean = 3.7 log10 per wet gram, sd = 1.1 log10), the high Ascaris ova counts in fecal sludges (prevalence = 88%; mean = 1.8 log10 per wet gram, sd = 0.95 log10), and the extended persistence and viability of Ascaris ova in soils. Even near-universal coverage of onsite sanitation may allow for sustained transmission of Ascaris under these conditions.
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Affiliation(s)
- Drew Capone
- Department
of Environmental and Occupational Health, School of Public Health, Indiana University, Bloomington, Indiana47401, United States
| | - Troy Barker
- Department
of Environmental Sciences and Engineering, Gillings School of Public
Health, University of North Carolina at
Chapel Hill, Chapel
Hill, North Carolina27599, United States
| | - Oliver Cumming
- Department
of Disease Control, London School of Hygiene
and Tropical Medicine, LondonWC1E 7HT, U.K.
| | - Abeoseh Flemister
- Department
of Biology, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina27599, United States
| | - Riley Geason
- Department
of Biology, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina27599, United States
| | - Elizabeth Kim
- Department
of Biology, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina27599, United States
| | - Jackie Knee
- Department
of Disease Control, London School of Hygiene
and Tropical Medicine, LondonWC1E 7HT, U.K.
| | - Yarrow Linden
- Department
of Environmental Sciences and Engineering, Gillings School of Public
Health, University of North Carolina at
Chapel Hill, Chapel
Hill, North Carolina27599, United States
| | - Musa Manga
- Department
of Environmental Sciences and Engineering, Gillings School of Public
Health, University of North Carolina at
Chapel Hill, Chapel
Hill, North Carolina27599, United States
| | - Mackenzie Meldrum
- Department
of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia30332, United States
| | - Rassul Nala
- Ministério
da Saúde, Instituto Nacional de Saúde
Maputo, Maputo1102, Mozambique
| | - Simrill Smith
- Department
of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia30332, United States
| | - Joe Brown
- Department
of Environmental Sciences and Engineering, Gillings School of Public
Health, University of North Carolina at
Chapel Hill, Chapel
Hill, North Carolina27599, United States
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Curtis AJ, Maisha F, Ajayakumar J, Bempah S, Ali A, Morris JG. The Use of Spatial Video to Map Dynamic and Challenging Environments: A Case Study of Cholera Risk in the Mujoga Relief Camp, D.R.C. Trop Med Infect Dis 2022; 7:tropicalmed7100257. [PMID: 36287998 PMCID: PMC9609570 DOI: 10.3390/tropicalmed7100257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/26/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
In this paper, we provide an overview of how spatial video data collection enriched with contextual mapping can be used as a universal tool to investigate sub-neighborhood scale health risks, including cholera, in challenging environments. To illustrate the method’s flexibility, we consider the life cycle of the Mujoga relief camp set up after the Nyiragongo volcanic eruption in the Democratic Republic of Congo on 22 May 2021. More specifically we investigate how these methods have captured the deteriorating conditions in a camp which is also experiencing lab-confirmed cholera cases. Spatial video data are collected every month from June 2021 to March 2022. These coordinate-tagged images are used to make monthly camp maps, which are then returned to the field teams for added contextual insights. At the same time, a zoom-based geonarrative is used to discuss the camp’s changes, including the cessation of free water supplies and the visible deterioration of toilet facilities. The paper concludes by highlighting the next data science advances to be made with SV mapping, including machine learning to automatically identify and map risks, and how these are already being applied in Mujoga.
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Affiliation(s)
- Andrew J. Curtis
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
- Correspondence: ; Tel.: +1-(626)-429-9476
| | - Felicien Maisha
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32601, USA
| | - Jayakrishnan Ajayakumar
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sandra Bempah
- Department of Geography, Kent State University, Kent, OH 44242, USA
| | - Afsar Ali
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32601, USA
- Department of Environmental & Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32601, USA
| | - J. Glenn Morris
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32601, USA
- College of Medicine, University of Florida, Gainesville, FL 32601, USA
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Contreras JD, Islam M, Mertens A, Pickering AJ, Kwong LH, Arnold BF, Benjamin-Chung J, Hubbard AE, Alam M, Sen D, Islam S, Rahman M, Unicomb L, Luby SP, Colford JM, Ercumen A. Influence of community-level sanitation coverage and population density on environmental fecal contamination and child health in a longitudinal cohort in rural Bangladesh. Int J Hyg Environ Health 2022; 245:114031. [PMID: 36058111 PMCID: PMC9489923 DOI: 10.1016/j.ijheh.2022.114031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/15/2022] [Accepted: 08/24/2022] [Indexed: 11/28/2022]
Abstract
Background Household-level sanitation interventions have had limited effects on child health or environmental contamination, potentially due to low community coverage. Higher community-level coverage with safely managed sanitation can reduce opportunities for disease transmission. Methods We estimated associations between community sanitation coverage, environmental fecal contamination, and child health among 360 compounds in the control arm of the WASH Benefits trial in rural Bangladesh (NCT01590095). In each compound, we enumerated E. coli in environmental samples and recorded the 7-day prevalence of caregiver-reported diarrheal disease and acute respiratory infections (ARI) in children under five. We observed indicators of latrine access and quality among all neighboring compounds within 100 m of study compounds. We defined community coverage as the proportion of neighboring compounds with (1) at least one latrine, and (2) exclusively hygienic latrines (improved facility observed to safely contain feces), within both 50 m and 100 m of study compounds. We assessed effect modification by population density and season. Results Adjusted for confounders, study compounds surrounded by 100% coverage of at least one latrine per compound within 50 m had slightly lower log10E. coli counts in stored water (Δlog = −0.13, 95% CI -0.26, −0.01), child hand rinses (Δlog = −0.13, 95% CI -0.24, −0.02), and caregiver hand rinses (Δlog = −0.16, 95% CI -0.29, −0.03) and marginally lower prevalence of diarrheal disease (prevalence ratio [PR] = 0.82, 95% CI 0.64, 1.04) and ARI (PR = 0.84, 95% CI 0.69, 1.03) compared to compounds surrounded by <100% coverage. Effects were similar but less pronounced at 100 m. At higher population densities, community latrine coverage was associated with larger reductions in E. coli on child and caregiver hands and prevalence of diarrheal disease. Coverage with exclusively hygienic latrines was not associated with any outcome. Conclusion Higher community sanitation coverage was associated with reduced fecal contamination and improved child health, with stronger effects at highly local scales (50m) and at high population densities. Our findings indicate that the relationship between community sanitation coverage, environmental contamination, and child health varies by definition of coverage, distance, and population density. This work highlights significant uncertainty around how to best measure sanitation coverage and the expected health effects of increasing sanitation coverage using a specific metric. Better understanding of community-level sanitation access is needed to inform policy for implementing sanitation systems that effectively protect community health.
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Affiliation(s)
- Jesse D Contreras
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, 27695, United States
| | - Mahfuza Islam
- Environmental Interventions Unit, Infectious Disease Division, icddr,b, Dhaka, 1212, Bangladesh
| | - Andrew Mertens
- Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, Berkeley, California, 94720, United States
| | - Amy J Pickering
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California, 94720, United States
| | - Laura H Kwong
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, 94720, United States
| | - Benjamin F Arnold
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, 94158, United States
| | - Jade Benjamin-Chung
- Department of Epidemiology and Population Health, Stanford University, Palo Alto, California, 94304, United States
| | - Alan E Hubbard
- Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, Berkeley, California, 94720, United States
| | - Mahfuja Alam
- Environmental Interventions Unit, Infectious Disease Division, icddr,b, Dhaka, 1212, Bangladesh
| | - Debashis Sen
- Environmental Interventions Unit, Infectious Disease Division, icddr,b, Dhaka, 1212, Bangladesh
| | - Sharmin Islam
- Environmental Interventions Unit, Infectious Disease Division, icddr,b, Dhaka, 1212, Bangladesh
| | - Mahbubur Rahman
- Environmental Interventions Unit, Infectious Disease Division, icddr,b, Dhaka, 1212, Bangladesh
| | - Leanne Unicomb
- Environmental Interventions Unit, Infectious Disease Division, icddr,b, Dhaka, 1212, Bangladesh
| | - Stephen P Luby
- Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, 94305, United States
| | - John M Colford
- Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, Berkeley, California, 94720, United States
| | - Ayse Ercumen
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, 27695, United States.
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Beard VA, Satterthwaite D, Mitlin D, Du J. Out of sight, out of mind: Understanding the sanitation crisis in global South cities. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 306:114285. [PMID: 35016141 PMCID: PMC8819159 DOI: 10.1016/j.jenvman.2021.114285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/21/2021] [Accepted: 12/09/2021] [Indexed: 05/28/2023]
Abstract
Global monitoring efforts do not provide a clear picture of the challenge of managing human waste at the city scale. Where cities do not provide universal access to publicly managed sanitation systems, households and communities find their own solutions resulting in a patchwork of approaches to removing human waste from places where people live. In dense urban environments, the absence of a coordinated approach can create serious public health problems. In the absence of comparable city-level data, we analyze primary and secondary data from 15 cities and 15 informal settlements in sub-Saharan Africa, South Asia, and Latin America. Across these regions, our study finds that 62 percent of human waste is not safely managed. We also find that, while many cities have a proportion of households connected to sewers, none of the 15 cities safely manage human waste at scale. In the absence of sewers, on-site fecal sludge management systems place enormous responsibility on households and private providers, and unaffordable sanitation options result in risky sanitation practices.
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Affiliation(s)
| | | | - Diana Mitlin
- University of Manchester, International Institute for Environmental Development, UK
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7
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Espira L, Aung T, Han K, Jagger P, Eisenberg JNS. Determinants of Pathogen Contamination of the Environment in the Greater Yangon Area, Myanmar. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16465-16476. [PMID: 34792323 DOI: 10.1021/acs.est.1c02887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent results from water, sanitation, and hygiene interventions highlight the need to better understand environmental influences on enteropathogen transmission. We quantified a range of viral, bacterial, and protozoal pathogens and one indicator, Enterococcus faecalis in soil and water from urban and rural sites in and around Yangon, Myanmar. We found that environmental characteristics associated with contamination differed by pathogens and substrates. In soil, bacterial pathogen gene counts were associated with elevation and drainage ditches (compared to stagnant water) (RR = 0.96, 95% CI 0.93, 0.99 and RR = 1.70, 95% CI 1.18, 2.45, respectively), while viral gene counts were associated with the presence of sanitation facilities within 50 m of the collection point (RR = 3.99, 95% CI 1.12, 14.24). In water, E. faecalis, total pathogen, and bacterial pathogen gene counts were associated with drainage ditches (RR = 1.86, 95% CI 1.27, 2.72, RR = 1.38 95% CI 1.09, 1.74, and RR = 1.38 95% CI 1.07, 1.77, respectively). E. faecalis, total pathogen, bacterial pathogen, and viral gene counts were associated with the presence of uncollected garbage within 50 m of the collection point (RR = 1.57, 95% CI 1.00, 2.47, RR = 1.52, 95% CI 1.16, 2.00, RR = 1.52, 95% CI 1.13, 2.06, and RR = 1.75, 95% CI 1.17, 2.61 respectively). Measuring the environment provides added specificity toward identifying important environmental pathways that require mitigation.
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Affiliation(s)
- Leon Espira
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ther Aung
- Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27516, United States
| | - Khin Han
- Department of Geography, West Yangon University, Yangon 13393, Myanmar
| | - Pamela Jagger
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph N S Eisenberg
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan 48109, United States
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Extended Spectrum Beta-Lactamase Escherichia coli in River Waters Collected from Two Cities in Ghana, 2018-2020. Trop Med Infect Dis 2021; 6:tropicalmed6020105. [PMID: 34203078 PMCID: PMC8293421 DOI: 10.3390/tropicalmed6020105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/15/2021] [Indexed: 11/16/2022] Open
Abstract
Infections by Extended-Spectrum Beta-Lactamase producing Escherichia coli (ESBL-Ec) are on the increase in Ghana, but the level of environmental contamination with this organism, which may contribute to growing Antimicrobial Resistance (AMR), is unknown. Using the WHO OneHealth Tricycle Protocol, we investigated the contamination of E. coli (Ec) and ESBL-Ec in two rivers in Ghana (Odaw in Accra and Okurudu in Kasoa) that receive effluents from human and animal wastewater hotspots over a 12-month period. Concentrations of Ec, ESBL-Ec and percent ESBL-Ec/Ec were determined per 100 mL sample. Of 96 samples, 94 (98%) were positive for ESBL-Ec. concentrations per 100 mL (MCs100) of ESBL-Ec and %ESBL-Ec from both rivers were 4.2 × 104 (IQR, 3.1 × 103–2.3 × 105) and 2.79 (IQR, 0.96–6.03), respectively. MCs100 were significantly lower in upstream waters: 1.8 × 104 (IQR, 9.0 × 103–3.9 × 104) as compared to downstream waters: 1.9 × 106 (IQR, 3.7 × 105–5.4 × 106). Both human and animal wastewater effluents contributed to the increased contamination downstream. This study revealed high levels of ESBL-Ec in rivers flowing through two cities in Ghana. There is a need to manage the sources of contamination as they may contribute to the acquisition and spread of ESBL-Ec in humans and animals, thereby contributing to AMR.
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Foster T, Falletta J, Amin N, Rahman M, Liu P, Raj S, Mills F, Petterson S, Norman G, Moe C, Willetts J. Modelling faecal pathogen flows and health risks in urban Bangladesh: Implications for sanitation decision making. Int J Hyg Environ Health 2021; 233:113669. [PMID: 33578186 DOI: 10.1016/j.ijheh.2020.113669] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 11/19/2020] [Accepted: 11/24/2020] [Indexed: 12/29/2022]
Abstract
Faecal-oral infections are a major component of the disease burden in low-income contexts, with inadequate sanitation seen as a contributing factor. However, demonstrating health effects of sanitation interventions - particularly in urban areas - has proved challenging and there is limited empirical evidence to support sanitation decisions that maximise health gains. This study aimed to develop, apply and validate a systems modelling approach to inform sanitation infrastructure and service decision-making in urban environments by examining enteric pathogen inputs, transport and reduction by various sanitation systems, and estimating corresponding exposure and public health impacts. The health effects of eight sanitation options were assessed in a low-income area in Dhaka, Bangladesh, with a focus on five target pathogens (Shigella, Vibrio cholerae, Salmonella Typhi, norovirus GII and Giardia). Relative to the sanitation base case in the study site (24% septic tanks, 5% holding tanks and 71% toilets discharging directly to open drains), comprehensive coverage of septic tanks was estimated to reduce the disease burden in disability-adjusted life years (DALYs) by 48-72%, while complete coverage of communal scale anaerobic baffled reactors was estimated to reduce DALYs by 67-81%. Despite these improvements, a concerning health risk persists with these systems as a result of effluent discharge to open drains, particularly when the systems are poorly managed. Other sanitation options, including use of constructed wetlands and small bore sewerage, demonstrated further reductions in local health risk, though several still exported pathogens into neighbouring areas, simply transferring risk to downstream communities. The study revealed sensitivity to and a requirement for further evidence on log reduction values for different sanitation systems under varying performance conditions, pathogen flows under flooding conditions as well as pathogen shedding and human exposure in typical low-income urban settings. Notwithstanding variability and uncertainties in input parameters, systems modelling can be a feasible and customisable approach to consider the relative health impact of different sanitation options across various contexts, and stands as a valuable tool to guide urban sanitation decision-making.
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Affiliation(s)
- Tim Foster
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
| | - Jay Falletta
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
| | - Nuhu Amin
- Environmental Interventions Unit, Infectious Disease Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
| | - Mahbubur Rahman
- Environmental Interventions Unit, Infectious Disease Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
| | - Pengbo Liu
- Center for Global Safe Water, Sanitation, and Hygiene, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
| | - Suraja Raj
- Center for Global Safe Water, Sanitation, and Hygiene, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
| | - Freya Mills
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
| | - Susan Petterson
- Water & Health Pty Ltd., 13 Lord St, North Sydney, NSW, 2060, Australia; School of Medicine, Griffith University, Parklands Drive, Southport, QLD, 4222, Australia.
| | - Guy Norman
- Water and Sanitation for the Urban Poor, 10 Queen Street Place, London, EC4R 1BE, UK.
| | - Christine Moe
- Center for Global Safe Water, Sanitation, and Hygiene, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
| | - Juliet Willetts
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
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Pathogen flows from on-site sanitation systems in low-income urban neighborhoods, Dhaka: A quantitative environmental assessment. Int J Hyg Environ Health 2020; 230:113619. [PMID: 32942223 DOI: 10.1016/j.ijheh.2020.113619] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 08/16/2020] [Accepted: 08/27/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND Despite wide usage of on-site sanitation, there is limited field-based evidence on the removal or release of pathogens from septic tanks and other primary treatment systems, such as anaerobic baffled reactors (ABR). In two low-income areas in Dhaka, we conducted a cross-sectional study to explore pathogen loads discharged from commonly used on-site sanitation-systems and their transport in nearby drains and waterways. METHODS We collected samples of drain water, drain sediment, canal water, and floodwater from April-October 2019. Sludge, supernatant, and effluent samples were also collected from septic tanks and ABRs. We investigated the presence and concentration of selected enteric pathogens (Shigella, Vibrio cholerae (V. cholerae), Salmonella Typhi (S. Typhi), Norovirus Genogroup-II (NoV-GII), and Giardia) and presence of Cryptosporidium in these samples using quantitative polymerase chain reaction (qPCR).The equivalent genome copies (EGC) of individual pathogens were estimated in each sample by interpolation of the mean Ct value to the corresponding standard curve and the dilution factor for each sample type. Absolute quantification was expressed as log10 EGC per 100 mL for the water samples and log10 EGC per gram for the sediment samples. RESULTS Among all samples tested (N = 151), 89% were contaminated with Shigella, 68% with V. cholerae and NoV-GII, 32% with Giardia, 17% with S. Typhi and 6% with Cryptosporidium. A wide range of concentration of pathogens [range: mean log10 concentration of Giardia = 0.74 EGC/100 mL in drain ultrafiltration samples to mean log10 concentration of NoV-GII and Giardia = 7.11 EGC/100 mL in ABR sludge] was found in all environmental samples. The highest pathogen concentrations were detected in open drains [range: mean log10 concentration = 2.50-4.94 EGC/100 mL], septic tank effluent [range: mean log10 concentration = 3.32-4.65 EGC/100 mL], and ABR effluent [range: mean log10 concentration = 2.72-5.13 EGC/100 mL]. CONCLUSIONS High concentrations of pathogens (particularly NoV-GII, V.cholerae and Shigella) were frequently detected in environmental samples from two low-income urban neighbourhoods of Dhaka city. The numerous environmental exposure pathways for children and adults make these findings of public health concern. These results should prompt rethinking of how to achieve safe sanitation solutions that protect public health in dense low-income areas. In particular, improved management and maintenance regimes, further treatment of liquid effluent from primary treatment processes, and appropriate application of onsite, decentralised and offsite sanitation systems given the local context.
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Reducing Groundwater Contamination from On-Site Sanitation in Peri-Urban Sub-Saharan Africa: Reviewing Transition Management Attributes towards Implementation of Water Safety Plans. SUSTAINABILITY 2020. [DOI: 10.3390/su12104210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
High urbanization in Sub-Saharan Africa (SSA) has resulted in increased peri-urban groundwater contamination by on-site sanitation. The World Health Organization introduced Water Safety Plans (WSP) towards the elimination of contamination risks to water supply systems; however, their application to peri-urban groundwater sources has been limited. Focusing on Uganda, Ghana, and Tanzania, this paper reviews limitations of the existing water regime in addressing peri-urban groundwater contamination through WSPs and normative attributes of Transition Management (TM) towards a sustainable solution. Microbial and nutrient contamination remain prevalent hazards in peri-urban SSA, arising from on-site sanitation within a water regime following Integrated Water Resources Management (IWRM) principles. Limitations to implementation of WSPs for peri-urban groundwater protection include policy diversity, with low focus on groundwater; institutional incoherence; highly techno-centric management tools; and limited regard for socio-cultural and urban-poor aspects. In contrast, TM postulates a prescriptive approach promoted by community-led frontrunners, with flexible and multi-domain actors, experimenting through socio-technical tools towards a shared vision. Thus, a unified risk-based management framework, harnessing attributes of TM and IWRM, is proposed towards improved WSP implementation. The framework could assist peri-urban communities and policymakers in formulating sustainable strategies to reduce groundwater contamination, thereby contributing to improved access to safe water.
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