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Mills F, Foster T, Kome A, Munankami R, Halcrow G, Ndungu A, Evans B, Willetts J. Indicators to complement global monitoring of safely managed on-site sanitation to understand health risks. NPJ CLEAN WATER 2024; 7:58. [PMID: 38979059 PMCID: PMC11227438 DOI: 10.1038/s41545-024-00353-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 06/24/2024] [Indexed: 07/10/2024]
Abstract
Halfway through the Sustainable Development Goal (SDG) period, there has been little research on the criteria for monitoring safely managed sanitation under SDG target 6.2. For reporting against SDGs, global indicators are necessarily limited and exclude many safety aspects from a public health perspective. Primary survey data from 31,784 households in seven countries in Asia and Africa were analysed, comparing estimates of safely managed on-site sanitation based on global indicators with five complementary indicators of safety: animal access to excreta, groundwater contamination, overdue emptying, entering containments to empty and inadequate protection during emptying. Application of additional criteria reduced the population with safely managed sanitation by 0.4-35% for specific indicators, with the largest impact due to the risk of groundwater contamination, animal access, and containments overdue for emptying. Combining these indicators across the service chain, excluding transport and treatment, found almost three-quarters of on-site systems currently assessed as safely managed with global indicators were considered unsafe based on complementary indicators. A more comprehensive assessment of safety of on-site sanitation can be achieved through these indicators, which could be integrated into national monitoring systems and used to inform sanitation investments that address local health-related risks.
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Affiliation(s)
- Freya Mills
- Institute for Sustainable Futures, University of Technology Sydney, Ultimo, NSW Australia
| | - Tim Foster
- Institute for Sustainable Futures, University of Technology Sydney, Ultimo, NSW Australia
| | - Antoinette Kome
- SNV Netherlands Development Organisation, The Hague, The Netherlands
| | - Rajeev Munankami
- SNV Netherlands Development Organisation, The Hague, The Netherlands
| | - Gabrielle Halcrow
- SNV Netherlands Development Organisation, The Hague, The Netherlands
| | - Antony Ndungu
- SNV Netherlands Development Organisation, The Hague, The Netherlands
| | - Barbara Evans
- School of Civil Engineering, University of Leeds, Leeds, UK
| | - Juliet Willetts
- Institute for Sustainable Futures, University of Technology Sydney, Ultimo, NSW Australia
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Capone D, Cumming O, Flemister A, Ilevbare V, Irish SR, Keenum I, Knee J, Nala R, Brown J. Sanitation in urban areas may limit the spread of antimicrobial resistance via flies. PLoS One 2024; 19:e0298578. [PMID: 38507457 PMCID: PMC10954131 DOI: 10.1371/journal.pone.0298578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 01/28/2024] [Indexed: 03/22/2024] Open
Abstract
Synanthropic filth flies are common where sanitation is poor and fecal wastes are accessible to them. These flies have been proposed as mechanical vectors for the localized transport of fecal microbes including antimicrobial resistant (AMR) organisms and associated antimicrobial resistance genes (ARGs), increasing exposure risks. We evaluated whether an onsite sanitation intervention in Maputo, Mozambique reduced the concentration of enteric bacteria and the frequency of detection of ARGs carried by flies collected in household compounds of low-income neighborhoods. Additionally, we assessed the phenotypic resistance profile of Enterobacteriaceae isolates recovered from flies during the pre-intervention phase. After fly enumeration at study compounds, quantitative polymerase chain reaction was used to quantify an enteric 16S rRNA gene (i.e., specific to a cluster of phylotypes corresponding to 5% of the human fecal microflora), 28 ARGs, and Kirby Bauer Disk Diffusion of Enterobacteriaceae isolates was utilized to assess resistance to eleven clinically relevant antibiotics. The intervention was associated with a 1.5 log10 reduction (95% confidence interval: -0.73, -2.3) in the concentration of the enteric 16S gene and a 31% reduction (adjusted prevalence ratio = 0.69, [0.52, 0.92]) in the mean number of ARGs per fly compared to a control group with poor sanitation. This protective effect was consistent across the six ARG classes that we detected. Enterobacteriaceae isolates-only from the pre-intervention phase-were resistant to a mean of 3.4 antibiotics out of the eleven assessed. Improving onsite sanitation infrastructure in low-income informal settlements may help reduce fly-mediated transmission of enteric bacteria and the ARGs carried by them.
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Affiliation(s)
- Drew Capone
- Department of Environmental and Occupational Health, Indiana University, Bloomington, Indiana, United States of America
| | - Oliver Cumming
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Abeoseh Flemister
- Roy Blunt NextGen Precision Health, University of Missouri, Columbia, Missouri, United States of America
- Department of Radiology, University of Missouri, Columbia, MO, United States of America
| | - Victor Ilevbare
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Seth R. Irish
- Epidemiology and Public Health Department, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Ishi Keenum
- Department of Civil, Environmental and Geospatial Engineering, Michigan Technological University, Houghton, Michigan, United States of America
| | - Jackie Knee
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Rassul Nala
- Ministério da Saúde de Moçambique, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Joe Brown
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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Mertens A, Arnold BF, Benjamin-Chung J, Boehm AB, Brown J, Capone D, Clasen T, Fuhrmeister ER, Grembi JA, Holcomb D, Knee J, Kwong LH, Lin A, Luby SP, Nala R, Nelson K, Njenga SM, Null C, Pickering AJ, Rahman M, Reese HE, Steinbaum L, Stewart JR, Thilakaratne R, Cumming O, Colford JM, Ercumen A. Is detection of enteropathogens and human or animal faecal markers in the environment associated with subsequent child enteric infections and growth: an individual participant data meta-analysis. Lancet Glob Health 2024; 12:e433-e444. [PMID: 38365415 PMCID: PMC10882208 DOI: 10.1016/s2214-109x(23)00563-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 11/13/2023] [Accepted: 11/28/2023] [Indexed: 02/18/2024]
Abstract
BACKGROUND Quantifying contributions of environmental faecal contamination to child diarrhoea and growth faltering can illuminate causal mechanisms behind modest health benefits in recent water, sanitation, and hygiene (WASH) trials. We aimed to assess associations between environmental detection of enteropathogens and human or animal microbial source tracking markers (MSTM) and subsequent child health outcomes. METHODS In this individual participant data meta-analysis we searched we searched PubMed, Embase, CAB Direct Global Health, Agricultural and Environmental Science Database, Web of Science, and Scopus for WASH intervention studies with a prospective design and concurrent control that measured enteropathogens or MSTM in environmental samples, or both, and subsequently measured enteric infections, diarrhoea, or height-for-age Z-scores (HAZ) in children younger than 5 years. We excluded studies that only measured faecal indicator bacteria. The initial search was done on Jan 19, 2021, and updated on March 22, 2023. One reviewer (AM) screened abstracts, and two independent reviewers (AM and RT) examined the full texts of short-listed articles. All included studies include at least one author that also contributed as an author to the present Article. Our primary outcomes were the 7-day prevalence of caregiver-reported diarrhoea and HAZ in children. For specific enteropathogens in the environment, primary outcomes also included subsequent child infection with the same pathogen ascertained by stool testing. We estimated associations using covariate-adjusted regressions and pooled estimates across studies. FINDINGS Data from nine published reports from five interventions studies, which included 8603 children (4302 girls and 4301 boys), were included in the meta-analysis. Environmental pathogen detection was associated with increased infection prevalence with the same pathogen and lower HAZ (ΔHAZ -0·09 [95% CI -0·17 to -0·01]) but not diarrhoea (prevalence ratio 1·22 [95% CI 0·95 to 1·58]), except during wet seasons. Detection of MSTM was not associated with diarrhoea (no pooled estimate) or HAZ (ΔHAZ -0·01 [-0·13 to 0·11] for human markers and ΔHAZ -0·02 [-0·24 to 0·21] for animal markers). Soil, children's hands, and stored drinking water were major transmission pathways. INTERPRETATION Our findings support a causal chain from pathogens in the environment to infection to growth faltering, indicating that the lack of WASH intervention effects on child growth might stem from insufficient reductions in environmental pathogen prevalence. Studies measuring enteropathogens in the environment should subsequently measure the same pathogens in stool to further examine theories of change between WASH, faecal contamination, and health. Given that environmental pathogen detection was predictive of infection, programmes targeting specific pathogens (eg, vaccinations and elimination efforts) can environmentally monitor the pathogens of interest for population-level surveillance instead of collecting individual biospecimens. FUNDING The Bill & Melinda Gates Foundation and the UK Foreign and Commonwealth Development Office.
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Affiliation(s)
- Andrew Mertens
- Division of Epidemiology, University of California, Berkeley, CA, USA; Division of Biostatistics, University of California, Berkeley, CA, USA.
| | - Benjamin F Arnold
- Francis I Proctor Foundation and Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Jade Benjamin-Chung
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA, USA
| | - Alexandria B Boehm
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Joe Brown
- Department of Environmental Science and Engineering, University of North Carolina, Gillings School of Global Public Health, Michael Hooker Research Center, Chapel Hill, NC, USA
| | - Drew Capone
- Department of Environmental and Occupational Health, Indiana University, Bloomington, IN, USA
| | - Thomas Clasen
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Erica R Fuhrmeister
- Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | | | - David Holcomb
- Department of Environmental Science and Engineering, University of North Carolina, Gillings School of Global Public Health, Michael Hooker Research Center, Chapel Hill, NC, USA
| | - Jackie Knee
- Department of Disease Control, London School of Tropical Medicine & Hygiene, London, UK
| | - Laura H Kwong
- Division of Environmental Health Sciences, University of California, Berkeley, CA, USA
| | - Audrie Lin
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, USA
| | - Stephen P Luby
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA, USA
| | - Rassul Nala
- Ministério da Saúde, Instituto Nacional de Saúde Maputo, Maputo, Mozambique
| | - Kara Nelson
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, CA, USA
| | | | | | - Amy J Pickering
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, CA, USA
| | - Mahbubur Rahman
- Environmental Interventions Unit, Infectious Diseases Division, Dhaka, Bangladesh
| | - Heather E Reese
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Lauren Steinbaum
- California Department of Toxic Substances Control, Sacramento, CA, USA
| | - Jill R Stewart
- Department of Environmental Science and Engineering, University of North Carolina, Gillings School of Global Public Health, Michael Hooker Research Center, Chapel Hill, NC, USA
| | | | - Oliver Cumming
- Department of Disease Control, London School of Tropical Medicine & Hygiene, London, UK
| | - John M Colford
- Division of Epidemiology, University of California, Berkeley, CA, USA
| | - Ayse Ercumen
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, USA
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Espira LM, Gessese B, Kassa BA, Wu CC, Riley J, Bedru S, Sahilu G, Desta A, Baye K, Jones AD, Love NG, Eisenberg JNS. Multiscalar Evaluation of the Water Distribution System and Diarrheal Disease Risk in Addis Ababa, Ethiopia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:13313-13324. [PMID: 37642551 PMCID: PMC10501120 DOI: 10.1021/acs.est.2c08976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 07/22/2023] [Accepted: 07/24/2023] [Indexed: 08/31/2023]
Abstract
Despite growing urbanization, our understanding of the impacts of water and sanitation on human health has largely come from studies in rural sectors. To this end, we collected data at both regional (water quality measures from water treatment systems) and community (cross-sectional surveys) scales to examine determinants of enteric pathogen infection and diarrheal disease among infants in Addis Ababa, Ethiopia. Regionally, the Legedadi water treatment plant had significantly lower heterotrophic plate counts, total coliform counts, and fecal coliform counts compared with the Gefersa water treatment plant. The number of pathogen types in infant stool also differed by plant. Decreases in chlorine levels and increases in the relative abundance of Gammaproteobacteria with distance from treatment plants suggest a compromised water distribution system. In communities, infants in households that obtained water from yard pipes or public taps had significantly lower odds of diarrhea compared to households that had water piped into their dwellings (OR = 0.35, 95% CI 0.16, 0.76, and OR = 0.39, 95% CI 0.15, 1.00, respectively). Similarly, infants in households that boiled or filtered water had significantly lower odds of diarrhea compared to households that did not treat water (OR = 0.40, 95% CI 0.19, 0.86 and OR = 0.23, 95% CI 0.06, 0.84, respectively). Integrating multiscalar data better informs the health impacts of water in urban settings.
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Affiliation(s)
- Leon M. Espira
- Department
of Epidemiology, University of Michigan
School of Public Health, Ann Arbor, Michigan 48109, United States
| | - Brook Gessese
- Ethiopian
Institute of Water Resources, Addis Ababa
University, Addis
Ababa 150461, Ethiopia
| | - Bayable A. Kassa
- Institute
of Biotechnology, Addis Ababa University, Addis Ababa 1176, Ethiopia
| | - Chia-Chen Wu
- Institute
of Environmental Engineering, National Yang
Ming Chiao Tung University, Hsinchu City 30010, Taiwan
| | - Joshua Riley
- Department
of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Seifedin Bedru
- School of
Civil and Environmental Engineering, Addis
Ababa University, Addis Ababa 1176, Ethiopia
| | - Geremew Sahilu
- School of
Civil and Environmental Engineering, Addis
Ababa University, Addis Ababa 1176, Ethiopia
| | - Adey Desta
- Department
of Microbial and Cellular Biology, Addis
Ababa University, Addis Ababa 1176, Ethiopia
| | - Kaleab Baye
- Center
for
Food Science and Nutrition, College of Natural and Computational Sciences, Addis Ababa University, Addis Ababa 1176, Ethiopia
| | - Andrew D. Jones
- Department
of Nutritional Sciences, University of Michigan
School of Public Health, Ann Arbor, Michigan 48109, United States
| | - Nancy G. Love
- Department
of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph N. S. Eisenberg
- Department
of Epidemiology, University of Michigan
School of Public Health, Ann Arbor, Michigan 48109, United States
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5
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Adhikari S, Hunter E, Vossenberg JVD, Thomas J. A review of latrine front-end characteristics associated with microbial infection risk; reveals a lack of pathogen density data. Int J Hyg Environ Health 2023; 254:114261. [PMID: 37734133 DOI: 10.1016/j.ijheh.2023.114261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/06/2023] [Accepted: 09/09/2023] [Indexed: 09/23/2023]
Abstract
Unsafe sanitation accounts for an estimated 898,000 global deaths annually. The faecal pathogen transmission pathway is complex with several possible routes. Latrine front-end characteristics and usage behaviours are one key transmission pathway for microbial pathogens, however, there has not yet been a synthesis of the available research. This review aims to compare the microbial infection risks with latrine front-end components including any quantified microbial densities within the household latrines. This review was conducted with no restriction on the geographical location of the research. Of 118 studies reviewed, only ten (8%) have quantified the microbial density inside the household latrines compared to 109 (92%) measuring the infection risks. The reported risks were most frequent for specific bacterial (n = 34), and helminths infections (n = 32) compared to diarrhoea (n = 23), combined (n = 15), protozoan (n = 4), and viral (n = 4) infections. The infections risk decreased for using latrines lying at a higher position on the sanitation ladder (for example flush latrines) compared to those lying lower (for example pit latrines). The trend was similar for using floor materials that were easier to clean and less favourable for pathogen survival inside the latrines (for example, concrete as opposed to earth). Faecal coliforms were reported highest on the surface of the squat pan (743 CFU/cm2) of pour-flush latrines and helminths on earth floors of pit latrines (1.5 eggs and larvae per gram of soil). Irrespective of latrine type and its position on the sanitation ladder, a dirty latrine, evidenced by a visible lack of cleanliness, significantly increased the risk for all infections. This study recommends that effective microbial infection risk reduction in latrines can be gained efficiently by ensuring washable surfaces and consistent cleaning practices. Future studies should include more rigorous measurements of microbial densities in various latrine types incorporating the different front-end components and usage behaviours.
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Affiliation(s)
- Sabita Adhikari
- School of Civil Engineering, The University of Sydney, Australia.
| | - Erin Hunter
- Department of Public Health Sciences, College of Behavioural, Social and Health Sciences, Clemson University, United States.
| | - Jack van de Vossenberg
- Water Supply, Sanitation and Environmental Engineering Department, IHE Delft Institute of Water Education, the Netherlands.
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Holcomb DA, Monteiro V, Capone D, António V, Chiluvane M, Cumbane V, Ismael N, Knee J, Kowalsky E, Lai A, Linden Y, Mataveia E, Nala R, Rao G, Ribeiro J, Cumming O, Viegas E, Brown J. Long-term impacts of an urban sanitation intervention on enteric pathogens in children in Maputo city, Mozambique: study protocol for a cross-sectional follow-up to the Maputo Sanitation (MapSan) trial 5 years postintervention. BMJ Open 2023; 13:e067941. [PMID: 37290945 PMCID: PMC10254709 DOI: 10.1136/bmjopen-2022-067941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 05/24/2023] [Indexed: 06/10/2023] Open
Abstract
INTRODUCTION We previously assessed the effect of an onsite sanitation intervention in informal neighbourhoods of urban Maputo, Mozambique on enteric pathogen detection in children after 2 years of follow-up (Maputo Sanitation (MapSan) trial, ClinicalTrials.gov: NCT02362932). We found significant reductions in Shigella and Trichuris prevalence but only among children born after the intervention was delivered. In this study, we assess the health impacts of the sanitation intervention after 5 years among children born into study households postintervention. METHODS AND ANALYSIS We are conducting a cross-sectional household study of enteric pathogen detection in child stool and the environment at compounds (household clusters sharing sanitation and outdoor living space) that received the pour-flush toilet and septic tank intervention at least 5 years prior or meet the original criteria for trial control sites. We are enrolling at least 400 children (ages 29 days to 60 months) in each treatment arm. Our primary outcome is the prevalence of 22 bacterial, protozoan, and soil transmitted helminth enteric pathogens in child stool using the pooled prevalence ratio across the outcome set to assess the overall intervention effect. Secondary outcomes include the individual pathogen detection prevalence and gene copy density of 27 enteric pathogens (including viruses); mean height-for-age, weight-for-age, and weight-for-height z-scores; prevalence of stunting, underweight, and wasting; and the 7-day period prevalence of caregiver-reported diarrhoea. All analyses are adjusted for prespecified covariates and examined for effect measure modification by age. Environmental samples from study households and the public domain are assessed for pathogens and faecal indicators to explore environmental exposures and monitor disease transmission. ETHICS AND DISSEMINATION Study protocols have been reviewed and approved by human subjects review boards at the Ministry of Health, Republic of Mozambique and the University of North Carolina at Chapel Hill. Deidentified study data will be deposited at https://osf.io/e7pvk/. TRIAL REGISTRATION NUMBER ISRCTN86084138.
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Affiliation(s)
- David A Holcomb
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Vanessa Monteiro
- Centro de Investigação e Treino em Saúde da Polana Caniço, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Drew Capone
- Department of Environmental and Occupational Health, School of Public Health, Indiana University, Bloomington, Indiana, USA
| | - Virgílio António
- Division of Biotechnology and Genetics, Instituto Nacional de Saúde, Marracuene, Mozambique
| | - Márcia Chiluvane
- Centro de Investigação e Treino em Saúde da Polana Caniço, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Victória Cumbane
- Centro de Investigação e Treino em Saúde da Polana Caniço, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Nália Ismael
- Division of Biotechnology and Genetics, Instituto Nacional de Saúde, Marracuene, Mozambique
| | - Jackie Knee
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Erin Kowalsky
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Amanda Lai
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Yarrow Linden
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Elly Mataveia
- Centro de Investigação e Treino em Saúde da Polana Caniço, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Rassul Nala
- Division of Parasitology, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Gouthami Rao
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jorge Ribeiro
- Centro de Investigação e Treino em Saúde da Polana Caniço, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Oliver Cumming
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Edna Viegas
- Centro de Investigação e Treino em Saúde da Polana Caniço, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Joe Brown
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
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Capone D, Bivins A, Brown J. Producing ratio measures of effect with quantitative microbial risk assessment. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2023. [PMID: 35689350 DOI: 10.17605/osf.io/jwzy9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Estimating the risk of infections or other outcomes incident to pathogen exposure is a primary goal of quantitative microbial risk assessment (QMRA). Such estimates are useful to predict population-level risks, to evaluate exposures based on normative or tolerable risk guidelines, and to interpret the likely public health relevance of microbial measurements in environmental media. To evaluate alternative control measures (interventions), ratio estimates of effect (e.g., odds and risk ratios) are needed that are more broadly interpretable in the health sciences and consistent with convention in epidemiology. In this paper, we propose a general method for estimating widely used ratio measures of effect derived from stochastic QMRA approaches, including the generation of appropriate confidence intervals. Such QMRA-derived ratios can be used as a basis for evaluating interventions via hypothesis testing and for inclusion in systematic reviews and meta-analyses in a form consistent with risk estimation approaches commonly used in epidemiology.
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Affiliation(s)
- Drew Capone
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Aaron Bivins
- Department of Civil & Environmental Engineering, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Joe Brown
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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8
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Capone D, Bivins A, Brown J. Producing ratio measures of effect with quantitative microbial risk assessment. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2023; 43:917-927. [PMID: 35689350 PMCID: PMC9734285 DOI: 10.1111/risa.13972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/12/2022] [Accepted: 05/12/2022] [Indexed: 05/06/2023]
Abstract
Estimating the risk of infections or other outcomes incident to pathogen exposure is a primary goal of quantitative microbial risk assessment (QMRA). Such estimates are useful to predict population-level risks, to evaluate exposures based on normative or tolerable risk guidelines, and to interpret the likely public health relevance of microbial measurements in environmental media. To evaluate alternative control measures (interventions), ratio estimates of effect (e.g., odds and risk ratios) are needed that are more broadly interpretable in the health sciences and consistent with convention in epidemiology. In this paper, we propose a general method for estimating widely used ratio measures of effect derived from stochastic QMRA approaches, including the generation of appropriate confidence intervals. Such QMRA-derived ratios can be used as a basis for evaluating interventions via hypothesis testing and for inclusion in systematic reviews and meta-analyses in a form consistent with risk estimation approaches commonly used in epidemiology.
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Affiliation(s)
- Drew Capone
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Aaron Bivins
- Louisiana State University, Baton Rouge, Louisiana, USA
| | - Joe Brown
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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9
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Mertens A, Arnold BF, Benjamin-Chung J, Boehm AB, Brown J, Capone D, Clasen T, Fuhrmeister E, Grembi JA, Holcomb D, Knee J, Kwong LH, Lin A, Luby SP, Nala R, Nelson K, Njenga SM, Null C, Pickering AJ, Rahman M, Reese HE, Steinbaum L, Stewart J, Thilakaratne R, Cumming O, Colford JM, Ercumen A. Effects of water, sanitation, and hygiene interventions on detection of enteropathogens and host-specific faecal markers in the environment: a systematic review and individual participant data meta-analysis. Lancet Planet Health 2023; 7:e197-e208. [PMID: 36889861 PMCID: PMC10009758 DOI: 10.1016/s2542-5196(23)00028-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/25/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Water, sanitation, and hygiene (WASH) improvements are promoted to reduce diarrhoea in low-income countries. However, trials from the past 5 years have found mixed effects of household-level and community-level WASH interventions on child health. Measuring pathogens and host-specific faecal markers in the environment can help investigate causal pathways between WASH and health by quantifying whether and by how much interventions reduce environmental exposure to enteric pathogens and faecal contamination from human and different animal sources. We aimed to assess the effects of WASH interventions on enteropathogens and microbial source tracking (MST) markers in environmental samples. METHODS We did a systematic review and individual participant data meta-analysis, which included searches from Jan 1, 2000, to Jan 5, 2023, from PubMed, Embase, CAB Direct Global Health, Agricultural and Environmental Science Database, Web of Science, and Scopus, of prospective studies with water, sanitation, or hygiene interventions and concurrent control group that measured pathogens or MST markers in environmental samples and measured child anthropometry, diarrhoea, or pathogen-specific infections. We used covariate-adjusted regression models with robust standard errors to estimate study-specific intervention effects and pooled effect estimates across studies using random-effects models. FINDINGS Few trials have measured the effect of sanitation interventions on pathogens and MST markers in the environment and they mostly focused on onsite sanitation. We extracted individual participant data on nine environmental assessments from five eligible trials. Environmental sampling included drinking water, hand rinses, soil, and flies. Interventions were consistently associated with reduced pathogen detection in the environment but effect estimates in most individual studies could not be distinguished from chance. Pooled across studies, we found a small reduction in the prevalence of any pathogen in any sample type (pooled prevalence ratio [PR] 0·94 [95% CI 0·90-0·99]). Interventions had no effect on the prevalence of MST markers from humans (pooled PR 1·00 [95% CI 0·88-1·13]) or animals (pooled PR 1·00 [95% CI 0·97-1·03]). INTERPRETATION The small effect of these sanitation interventions on pathogen detection and absence of effects on human or animal faecal markers are consistent with the small or null health effects previously reported in these trials. Our findings suggest that the basic sanitation interventions implemented in these studies did not contain human waste and did not adequately reduce exposure to enteropathogens in the environment. FUNDING Bill and Melinda Gates Foundation and the UK Foreign and Commonwealth Development Office.
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Affiliation(s)
- Andrew Mertens
- Division of Epidemiology and Biostatistics, University of California, Berkeley, CA, USA.
| | - Benjamin F Arnold
- Francis I Proctor Foundation and Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Jade Benjamin-Chung
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA, USA
| | - Alexandria B Boehm
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Joe Brown
- Department of Environmental Science and Engineering, Gillings School of Global Public Health, Michael Hooker Research Center, University of North Carolina, Chapel Hill, NC, USA
| | - Drew Capone
- Department of Environmental and Occupational Health, Indiana University Bloomington, Bloomington, IN, USA
| | - Thomas Clasen
- Department of Environmental Health, Rollins School of Public Health, Emory University, NE, Atlanta, GA, USA
| | - Erica Fuhrmeister
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | | | - David Holcomb
- Department of Environmental Science and Engineering, Gillings School of Global Public Health, Michael Hooker Research Center, University of North Carolina, Chapel Hill, NC, USA
| | - Jackie Knee
- Department of Disease Control, London School of Tropical Medicine & Hygiene, London, UK
| | - Laura H Kwong
- Division of Environmental Health Sciences, University of California, Berkeley, CA, USA
| | - Audrie Lin
- Department of Biobehavioral Health, Pennsylvania State University, PA, USA
| | - Stephen P Luby
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA, USA
| | - Rassul Nala
- Ministério da Saúde, Instituto Nacional de Saúde Maputo, Maputo, Mozambique
| | - Kara Nelson
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, CA, USA
| | | | | | - Amy J Pickering
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, CA, USA
| | - Mahbubur Rahman
- Environmental Interventions Unit, Infectious Diseases Division, Dhaka, Bangladesh
| | - Heather E Reese
- Department of Environmental Health, Rollins School of Public Health, Emory University, NE, Atlanta, GA, USA
| | - Lauren Steinbaum
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA
| | - Jill Stewart
- Department of Environmental Science and Engineering, Gillings School of Global Public Health, Michael Hooker Research Center, University of North Carolina, Chapel Hill, NC, USA
| | - Ruwan Thilakaratne
- Division of Epidemiology and Biostatistics, University of California, Berkeley, CA, USA
| | - Oliver Cumming
- Department of Disease Control, London School of Tropical Medicine & Hygiene, London, UK
| | - John M Colford
- Division of Epidemiology and Biostatistics, University of California, Berkeley, CA, USA
| | - Ayse Ercumen
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, USA
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10
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Capone D, Adriano Z, Cumming O, Irish SR, Knee J, Nala R, Brown J. Urban Onsite Sanitation Upgrades and Synanthropic Flies in Maputo, Mozambique: Effects on Enteric Pathogen Infection Risks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:549-560. [PMID: 36516327 PMCID: PMC9835884 DOI: 10.1021/acs.est.2c06864] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Synanthropic filth flies transport enteric pathogens from feces to food, which upon consumption poses an infection risk. We evaluated the effect of an onsite sanitation intervention─including fly control measures─in Maputo, Mozambique, on the risk of infection from consuming fly-contaminated food. After enumerating flies at intervention and control sites, we cultured fecal indicator bacteria, quantified gene copies for 22 enteric pathogens via reverse transcription quantitative polymerase chain reaction (RT-qPCR), and developed quantitative microbial risk assessment (QMRA) models to estimate annual risks of infection attributable to fly-contaminated foods. We found that the intervention reduced fly counts at latrine entrances by 69% (aRR = 0.31, [0.13, 0.75]) but not at food preparation areas (aRR = 0.92, [0.33, 2.6]). Half of (23/46) of individual flies were positive for culturable Escherichia coli, and we detected ≥1 pathogen gene from 45% (79/176) of flies, including enteropathogenic E. coli (37/176), adenovirus (25/176), Giardia spp. (13/176), and Trichuris trichiura (12/176). We detected ≥1 pathogen gene from half the flies caught in control (54%, 30/56) and intervention compounds (50%, 17/34) at baseline, which decreased 12 months post-intervention to 43% (23/53) at control compounds and 27% (9/33) for intervention compounds. These data indicate flies as a potentially important mechanical vector for enteric pathogen transmission in this setting. The intervention may have reduced the risk of fly-mediated enteric infection for some pathogens, but infrequent detection resulted in wide confidence intervals; we observed no apparent difference in infection risk between groups in a pooled estimate of all pathogens assessed (aRR = 0.84, [0.61, 1.2]). The infection risks posed by flies suggest that the design of sanitation systems and service delivery should include fly control measures to prevent enteric pathogen transmission.
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Affiliation(s)
- Drew Capone
- Department
of Environmental and Occupational Health, School of Public Health, Indiana University, 2719 E 10th St, Bloomington, Indiana47401, United States
| | - Zaida Adriano
- WE
Consult ltd, 177 Rua
Tomas Ribeiro, Maputo1102, Mozambique
| | - Oliver Cumming
- Department
of Disease Control, London School of Hygiene
and Tropical Medicine, LondonWC1E 7HT, United
Kingdom
| | - Seth R. Irish
- Epidemiology
and Public Health Department, Swiss Tropical
and Public Health Institute, Kreuzstrasse 2, Allschwil4123, Switzerland
| | - Jackie Knee
- Department
of Disease Control, London School of Hygiene
and Tropical Medicine, LondonWC1E 7HT, United
Kingdom
| | - Rassul Nala
- Ministério
da Saúde, Instituto Nacional de Saúde
Maputo, Maputo1102, Mozambique
| | - 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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11
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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: 8] [Impact Index Per Article: 4.0] [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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12
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Konopka JK, Chatterjee P, LaMontagne C, Brown J. Environmental impacts of mass drug administration programs: exposures, risks, and mitigation of antimicrobial resistance. Infect Dis Poverty 2022; 11:78. [PMID: 35773680 PMCID: PMC9243877 DOI: 10.1186/s40249-022-01000-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/09/2022] [Indexed: 01/05/2023] Open
Abstract
Mass drug administration (MDA) of antimicrobials has shown promise in the reduction and potential elimination of a variety of neglected tropical diseases (NTDs). However, with antimicrobial resistance (AMR) becoming a global crisis, the risks posed by widespread antimicrobial use need to be evaluated. As the role of the environment in AMR emergence and dissemination has become increasingly recognized, it is likewise crucial to establish the role of MDA in environmental AMR pollution, along with the potential impacts of such pollution. This review presents the current state of knowledge on the antimicrobial compounds, resistant organisms, and antimicrobial resistance genes in MDA trials, routes of these determinants into the environment, and their persistence and ecological impacts, particularly in low and middle-income countries where these trials are most common. From the few studies directly evaluating AMR outcomes in azithromycin MDA trials, it is becoming apparent that MDA efforts can increase carriage and excretion of resistant pathogens in a lasting way. However, research on these outcomes for other antimicrobials used in MDA trials is sorely needed. Furthermore, while paths of AMR determinants from human waste to the environment and their persistence thereafter are supported by the literature, quantitative information on the scope and likelihood of this is largely absent. We recommend some mitigative approaches that would be valuable to consider in future MDA efforts. This review stands to be a valuable resource for researchers and policymakers seeking to evaluate the impacts of MDA.
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Affiliation(s)
- Joanna K Konopka
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Pranab Chatterjee
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Connor LaMontagne
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7431, USA
| | - Joe Brown
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7431, USA
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13
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Rahman M, Islam M, Doza S, Naser AM, Shoab AK, Rosenbaum J, Islam MS, Unicomb L, Clasen TF, Ercumen A. Higher helminth ova counts and incomplete decomposition in sand-enveloped latrine pits in a coastal sub-district of Bangladesh. PLoS Negl Trop Dis 2022; 16:e0010495. [PMID: 35737672 PMCID: PMC9223371 DOI: 10.1371/journal.pntd.0010495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 05/13/2022] [Indexed: 11/19/2022] Open
Abstract
Pit latrines are the most common latrine technology in rural Bangladesh, and untreated effluent from pits can directly contaminate surrounding aquifers. Sand barriers installed around the latrine pit can help reduce contamination but can also alter the decomposition of the fecal sludge and accelerate pit fill-up, which can counteract their benefits. We aimed to evaluate whether there was a difference in decomposition of fecal sludge and survival of soil-transmitted helminth (STH) ova among latrines where a 50-cm sand barrier was installed surrounding and at the bottom of the pit, compared to latrines without a sand barrier, in coastal Bangladesh. We assessed decomposition in latrine pits by measuring the carbon-nitrogen (C/N) ratio of fecal sludge. We enumerated Ascaris lumbricoides and Trichuris trichiura ova in the pit following 18 and 24 months of latrine use. We compared these outcomes between latrines with and without sand barriers using generalized linear models with robust standard errors to adjust for clustering at the village level. The C/N ratio in latrines with and without a sand barrier was 13.47 vs. 22.64 (mean difference: 9.16, 95% CI: 0.15, 18.18). Pits with sand barriers filled more quickly and were reportedly emptied three times more frequently than pits without; 27/34 latrines with sand barriers vs. 9/34 latrines without barriers were emptied in the previous six months. Most reported disposal methods were unsafe. Compared to latrines without sand barriers, latrines with sand barriers had significantly higher log10 mean counts of non-larvated A. lumbricoides ova (log10 mean difference: 0.35, 95% CI: 0.12, 0.58) and T. trichiura ova (log10 mean difference: 0.47, 95% CI: 0.20, 0.73). Larvated ova counts were similar for the two types of latrines for both A. lumbricoides and T. trichiura. Our findings suggest that sand barriers help contain helminth ova within the pits but pits with barriers fill up more quickly, leading to more frequent emptying of insufficiently decomposed fecal sludge. Further research is required on latrine technologies that can both isolate pathogens from the environment and achieve rapid decomposition.
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Affiliation(s)
- Mahbubur Rahman
- Environmental Intervention Unit, Infectious Disease Division, icddr,b, Dhaka, Bangladesh
| | - Mahfuza Islam
- Environmental Intervention Unit, Infectious Disease Division, icddr,b, Dhaka, Bangladesh
| | - Solaiman Doza
- Environmental Intervention Unit, Infectious Disease Division, icddr,b, Dhaka, Bangladesh
| | - Abu Mohammed Naser
- Gangarosa Department of Environmental Health Sciences, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
- Division of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, University of Memphis, Tennessee, United States of America
| | - Abul Kasham Shoab
- Environmental Intervention Unit, Infectious Disease Division, icddr,b, Dhaka, Bangladesh
| | | | - Md. Shariful Islam
- Department of Agricultural Chemistry, Patuakhali Science and Technology University, Patuakhali, Bangladesh
| | - Leanne Unicomb
- Environmental Intervention Unit, Infectious Disease Division, icddr,b, Dhaka, Bangladesh
| | - Thomas F. Clasen
- Gangarosa Department of Environmental Health Sciences, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - Ayse Ercumen
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, United States of America
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14
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Kapwata T, Kunene Z, Wernecke B, Lange S, Howard G, Nijhawan A, Wright CY. Applying a WASH Risk Assessment Tool in a Rural South African Setting to Identify Risks and Opportunities for Climate Resilient Communities. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19052664. [PMID: 35270357 PMCID: PMC8909929 DOI: 10.3390/ijerph19052664] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 02/01/2023]
Abstract
Climate change threatens the health and well-being of populations. We conducted a risk assessment of two climate-related variables (i.e., temperature and rainfall) and associated water, sanitation and hygiene (WASH)-related exposures and vulnerabilities for people living in Mopani District, Limpopo province, South Africa. Primary and secondary data were applied in a qualitative and quantitative assessment to generate classifications of risk (i.e., low, medium, or high) for components of hazard/threat, human exposure, and human vulnerability. Climate-related threats were likely to impact human health due to the relatively high risk of waterborne diseases and WASH-associated pathogens. Vulnerabilities that increased the susceptibility of the population to these adverse outcomes included environmental, human, physical infrastructure, and political and institutional elements. People of low socio-economic status were found to be least likely to cope with changes in these hazards. By identifying and assessing the risk to sanitation services and water supply, evidence exists to inform actions of government and WASH sector partners. This evidence should also be used to guide disaster risk reduction, and climate change and human health adaptation planning.
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Affiliation(s)
- Thandi Kapwata
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg 2094, South Africa; (T.K.); (Z.K.); (B.W.)
- Department of Environmental Health, Faculty of Health Sciences, University of Johannesburg, Johannesburg 2006, South Africa
| | - Zamantimande Kunene
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg 2094, South Africa; (T.K.); (Z.K.); (B.W.)
| | - Bianca Wernecke
- Environment and Health Research Unit, South African Medical Research Council, Johannesburg 2094, South Africa; (T.K.); (Z.K.); (B.W.)
- Department of Environmental Health, Faculty of Health Sciences, University of Johannesburg, Johannesburg 2006, South Africa
| | - Samantha Lange
- Water and Health Research Centre, Faculty of Health Sciences, University of Johannesburg, Johannesburg 2006, South Africa;
| | - Guy Howard
- Department of Civil Engineering, Cabot Institute, University of Bristol, Bristol BS8 1TU, UK;
| | - Anisha Nijhawan
- Department of Civil Engineering, University of Bristol, Bristol BS8 1TU, UK;
| | - Caradee Y. Wright
- Environment and Health Research Unit, South African Medical Research Council, Pretoria 0001, South Africa
- Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria 0001, South Africa
- Correspondence: ; Tel.: +27-12-339-8543
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15
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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: 4] [Impact Index Per Article: 1.3] [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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16
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Holcomb DA, Knee J, Capone D, Sumner T, Adriano Z, Nalá R, Cumming O, Brown J, Stewart JR. Impacts of an Urban Sanitation Intervention on Fecal Indicators and the Prevalence of Human Fecal Contamination in Mozambique. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:11667-11679. [PMID: 34382777 PMCID: PMC8429117 DOI: 10.1021/acs.est.1c01538] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fecal source tracking (FST) may be useful to assess pathways of fecal contamination in domestic environments and to estimate the impacts of water, sanitation, and hygiene (WASH) interventions in low-income settings. We measured two nonspecific and two human-associated fecal indicators in water, soil, and surfaces before and after a shared latrine intervention from low-income households in Maputo, Mozambique, participating in the Maputo Sanitation (MapSan) trial. Up to a quarter of households were impacted by human fecal contamination, but trends were unaffected by improvements to shared sanitation facilities. The intervention reduced Escherichia coli gene concentrations in soil but did not impact culturable E. coli or the prevalence of human FST markers in a difference-in-differences analysis. Using a novel Bayesian hierarchical modeling approach to account for human marker diagnostic sensitivity and specificity, we revealed a high amount of uncertainty associated with human FST measurements and intervention effect estimates. The field of microbial source tracking would benefit from adding measures of diagnostic accuracy to better interpret findings, particularly when FST analyses convey insufficient information for robust inference. With improved measures, FST could help identify dominant pathways of human and animal fecal contamination in communities and guide the implementation of effective interventions to safeguard health.
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Affiliation(s)
- David A. Holcomb
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States of America
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States of America
| | - Jackie Knee
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States of America
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Drew Capone
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States of America
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States of America
| | - Trent Sumner
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States of America
| | | | - Rassul Nalá
- Instituto Nacional de Saúde, Ministério da Saúde, Maputo, Mozambique
| | - Oliver Cumming
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Joe Brown
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States of America
| | - Jill R. Stewart
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States of America
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