Jenna Davis

All Publications

• Age-related changes to environmental exposure: variation in the frequency that young children place hands and objects in their mouths. Journal of exposure science & environmental epidemiology Kwong, L. H., Ercumen, A., Pickering, A. J., Unicomb, L., Davis, J., Luby, S. P. 2019

  Abstract

  Children are exposed to environmental contaminants through direct ingestion of water, food, soil, and feces, and through indirect ingestion due to mouthing hands and objects. We quantified ingestion among 30 rural Bangladeshi children<4 years old, recording every item touched or mouthed during 6-h video observations that occurred annually for 3 years. We calculated the frequency and duration of mouthing and the prevalence of mouth contacts with soil and feces. We compared the mouthing frequency distributions to those from US children to evaluate the appropriateness of applying the US data to the Bangladeshi context. Median hand mouthing frequency was 97-160times/h and object mouthing 23-50times/h among the five age groups assessed. For more than half of the children, >75% of all hand mouthing was associated with eating. The frequency of hand mouthing not related to eating was similar to the frequency of all hand-mouthing among childrenin the US. Object-mouthing frequency was higher among Bangladeshi children compared to US children. There was low intra-child correlation of mouthing frequencies over our longitudinal visits. Our results suggest that children's hand- and object-mouthing vary by geography and culture and that future exposure assessments can be cross-sectional if the goal is to estimate population-level distributions of mouthing frequencies. Of all observations, a child consumed soil in 23% and feces in 1%.

  View details for DOI 10.1038/s41370-019-0115-8

  View details for PubMedID 30728484

• Pathways to sustainability: A fuzzy-set qualitative comparative analysis of rural water supply programs JOURNAL OF CLEANER PRODUCTION Marks, S. J., Kumpel, E., Guo, J., Bartram, J., Davis, J. 2018; 205: 789–98

  View details for DOI 10.1016/j.jclepro.2018.09.029

  View details for Web of Science ID 000449133300062

• Costs and benefits of biogas recovery from communal anaerobic digesters treating domestic wastewater: Evidence from peri-urban Zambia JOURNAL OF ENVIRONMENTAL MANAGEMENT Laramee, J., Tilmans, S., Davis, J. 2018; 210: 23–35

  Abstract

  Communal anaerobic digesters (ADs) have been promoted as a waste-to-energy strategy that can provide sanitation and clean energy co-benefits. However, little empirical evidence is available regarding the performance of such systems in field conditions. This study assesses the wastewater treatment efficiency, energy production, greenhouse gas (GHG) emissions, and financial costs and benefits of communal ADs used for domestic wastewater treatment in Zambia. Primary data on the technical performance of 15 ADs were collected over a 6-month period and in-person interviews were conducted with heads of 120 households. Findings from this study suggest that ADs offer comparable wastewater treatment efficiencies and greater GHG emission reduction benefits relative to conventional septic tanks (STs), with the greatest benefits in settings with reliable access to water, use of low efficiency solid fuels and with sufficient demand for biogas in proximity to supply. However, absent a mechanism to monetize additional benefits from biogas recovery, ADs in this context will not be a financially attractive investment relative to STs. Our financial analysis suggests that, under the conditions in this study, a carbon price of US$9 to $28 per tCO2e is necessary for positive investment in ADs relative to STs. Findings from this study contribute empirical evidence on ADs as a sanitation and clean energy strategy, identify conditions under which the greatest benefits are likely to accrue and inform international climate efforts on the carbon price required to attract investment in emissions reduction projects such as ADs.

  View details for DOI 10.1016/j.jenvman.2017.12.064

  View details for Web of Science ID 000425559900003

  View details for PubMedID 29329005

• Can you taste it? Taste detection and acceptability thresholds for chlorine residual in drinking water in Dhaka, Bangladesh SCIENCE OF THE TOTAL ENVIRONMENT Crider, Y., Sultana, S., Unicomb, L., Davis, J., Luby, S. P., Pickering, A. J. 2018; 613: 840–46

  Abstract

  Chlorination is a low-cost, effective method for drinking water treatment, but aversion to the taste or smell of chlorinated water can limit use of chlorine treatment products. Forced choice triangle tests were used to evaluate chlorine detection and acceptability thresholds for two common types of chlorine among adults in Dhaka, Bangladesh, where previous studies have found low sustained uptake of chlorine water treatment products. The median detection threshold was 0.70mg/L (n=25, SD=0.57) for water dosed with liquid sodium hypochlorite (NaOCl) and 0.73mg/L (n=25, SD=0.83) for water dosed with solid sodium dichloroisocyanurate (NaDCC). Median acceptability thresholds (based on user report) were 1.16mg/L (SD=0.70) for NaOCl and 1.26mg/L (SD=0.67) for NaDCC. There was no significant difference in detection or acceptability thresholds for dosing with NaOCl versus NaDCC. Although users are willing to accept treated water in which they can detect the taste of chlorine, their acceptability limit is well below the 2.0mg/L that chlorine water treatment products are often designed to dose. For some settings, reducing dose may increase adoption of chlorinated water while still providing effective disinfection.

  View details for DOI 10.1016/j.scitotenv.2017.09.135

  View details for Web of Science ID 000414160500087

  View details for PubMedID 28942317

• Fecal Contamination on Produce from Wholesale and Retail Food Markets in Dhaka, Bangladesh AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE Harris, A. R., Islam, M., Unicomb, L., Boehm, A. B., Luby, S., Davis, J., Pickering, A. J. 2018; 98 (1): 287–94

  Abstract

  Fresh produce items can become contaminated with enteric pathogens along the supply chain at the preharvest (e.g., irrigation water, soil, fertilizer) or postharvest (e.g., vendor handling or consumer handling) stages. This study assesses the concentrations of fecal indicator bacteria Escherichia coli, enterococci (ENT), and Bacteriodales on surfaces of carrots, eggplants, red amaranth leaves, and tomatoes obtained from both a wholesale market (recently harvested) and neighborhood retail markets in Dhaka, Bangladesh. We detected E. coli in 100% of carrot and red amaranth rinses, 92% of eggplant rinses, and 46% of tomato rinses. Using a molecular microbial source tracking assay, we found that 32% of produce samples were positive for ruminant fecal contamination. Fecal indicator bacteria were more likely to be detected on produce collected in retail markets compared with that in the wholesale market; retail market produce were 1.25 times more likely to have E. coli detected (P = 0.03) and 1.24 times more likely to have ENT detected (P = 0.03) as compared with wholesale market produce. Bacteriodales was detected in higher concentrations in retail market produce samples compared with wholesale market produce samples (0.40 log10 gene copies per 100 cm2 higher, P = 0.03). Our results suggest that ruminant and general fecal contamination of produce in markets in Dhaka is common, and suggest that unsanitary conditions in markets are an important source of produce fecal contamination postharvest.

  View details for DOI 10.4269/ajtmh.17-0255

  View details for Web of Science ID 000430950900054

  View details for PubMedID 29165214

  View details for PubMedCentralID PMC5928698

• Soil-Transmitted Helminth Eggs Are Present in Soil at Multiple Locations within Households in Rural Kenya PLOS ONE Steinbaum, L., Njenga, S. M., Kihara, J., Boehm, A. B., Davis, J., Null, C., Pickering, A. J. 2016; 11 (6)

  Abstract

  Almost one-quarter of the world's population is infected with soil-transmitted helminths (STH). We conducted a study to determine the prevalence and location of STH-Ascaris, Trichuris, and hookworm spp.-egg contamination in soil within rural household plots in Kenya. Field staff collected soil samples from July to September 2014 from the house entrance and the latrine entrance of households in Kakamega County; additional spatial sampling was conducted at a subset of households (N = 22 samples from 3 households). We analyzed soil samples using a modified version of the US Environmental Protection Agency (EPA) method for enumerating Ascaris in biosolids. We found 26.8% of households had one or more species of STH eggs present in the soil in at least one household location (n = 18 out of 67 households), and Ascaris was the most commonly detected STH (19.4%, n = 13 out of 67 households). Prevalence of STH eggs in soil was equally likely at the house entrance (19.4%, N = 67) as at the latrine entrance (11.3%, N = 62) (p = 0.41). We also detected STH eggs at bathing and food preparation areas in the three houses revisited for additional spatial sampling, indicating STH exposure can occur at multiple sites within a household plot, not just near the latrine. The highest concentration of eggs in one house occurred in the child's play area. Our findings suggest interventions to limit child exposure to household soil could complement other STH control strategies.

  View details for DOI 10.1371/journal.pone.0157780

  View details for Web of Science ID 000378393600017

  View details for PubMedID 27341102

  View details for PubMedCentralID PMC4920396

• Hand- and Object-Mouthing of Rural Bangladeshi Children 3-18 Months Old INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH Kwong, L. H., Ercumen, A., Pickering, A. J., Unicomb, L., Davis, J., Luby, S. P. 2016; 13 (6)

  Abstract

  Children are exposed to environmental contaminants by placing contaminated hands or objects in their mouths. We quantified hand- and object-mouthing frequencies of Bangladeshi children and determined if they differ from those of U.S. children to evaluate the appropriateness of applying U.S. exposure models in other socio-cultural contexts. We conducted a five-hour structured observation of the mouthing behaviors of 148 rural Bangladeshi children aged 3-18 months. We modeled mouthing frequencies using 2-parameter Weibull distributions to compare the modeled medians with those of U.S. children. In Bangladesh the median frequency of hand-mouthing was 37.3 contacts/h for children 3-6 months old, 34.4 contacts/h for children 6-12 months old, and 29.7 contacts/h for children 12-18 months old. The median frequency of object-mouthing was 23.1 contacts/h for children 3-6 months old, 29.6 contacts/h for children 6-12 months old, and 15.2 contacts/h for children 12-18 months old. At all ages both hand- and object-mouthing frequencies were higher than those of U.S. children. Mouthing frequencies were not associated with child location (indoor/outdoor). Using hand- and object-mouthing exposure models from U.S. and other high-income countries might not accurately estimate children's exposure to environmental contaminants via mouthing in low- and middle-income countries.

  View details for DOI 10.3390/ijerph13060563

  View details for Web of Science ID 000378860100042

  View details for PubMedID 27271651

  View details for PubMedCentralID PMC4924020

• Ruminants Contribute Fecal Contamination to the Urban Household Environment in Dhaka, Bangladesh ENVIRONMENTAL SCIENCE & TECHNOLOGY Harris, A. R., Pickering, A. J., Harris, M., Doza, S., Islam, M. S., Unicomb, L., Luby, S., Davis, J., Boehm, A. B. 2016; 50 (9): 4642-4649

  Abstract

  In Dhaka, Bangladesh, the sensitivity and specificity of three human, three ruminant, and one avian source-associated QPCR microbial source tracking assays were evaluated using fecal samples collected on site. Ruminant-associated assays performed well, whereas the avian and human assays exhibited unacceptable cross-reactions with feces from other hosts. Subsequently, child hand rinses (n = 44) and floor sponge samples (n = 44) from low-income-households in Dhaka were assayed for fecal indicator bacteria (enterococci, Bacteroidales, and Escherichia coli) and a ruminant-associated bacterial target (BacR). Mean enterococci concentrations were of 100 most probable number (MPN)/2 hands and 1000 MPN/225 cm(2) floor. Mean concentrations of Bacteroidales were 10(6) copies/2 hands and 10(5) copies/225 cm(2) floor. E. coli were detected in a quarter of hand rinse and floor samples. BacR was detected in 18% of hand rinse and 27% of floor samples. Results suggest that effective household fecal management should account not only for human sources of contamination but also for animal sources. The poor performance of the human-associated assays in the study area calls into the question the feasibility of developing a human-associated marker in urban slum environments, where domestic animals are exposed to human feces that have been disposed in pits and open drains.

  View details for DOI 10.1021/acs.est.5b06282

  View details for Web of Science ID 000375521400007

  View details for PubMedID 27045990

• Field trial of an automated batch chlorinator system at shared water points in an urban community of Dhaka, Bangladesh JOURNAL OF WATER SANITATION AND HYGIENE FOR DEVELOPMENT Amin, N., Crider, Y. S., Unicomb, L., Das, K. K., Gope, P. S., Mahmud, Z. H., Islam, M. S., Davis, J., Luby, S. P., Pickering, A. J. 2016; 6 (1): 32-41

  View details for DOI 10.2166/washdev.2016.027

  View details for Web of Science ID 000374578500004

• User perceptions of and willingness to pay for household container-based sanitation services: experience from Cap Haitien, Haiti ENVIRONMENT AND URBANIZATION Russel, K., Tilmans, S., Kramer, S., Sklar, R., Tillias, D., Davis, J. 2015; 27 (2): 525-540

  View details for DOI 10.1177/0956247815596522

  View details for Web of Science ID 000362491200011

• Quantification of Human Norovirus GII on Hands of Mothers with Children Under the Age of Five Years in Bagamoyo, Tanzania. The American journal of tropical medicine and hygiene Mattioli, M. C., Davis, J., Mrisho, M., Boehm, A. B. 2015; 93 (3): 478-484

  Abstract

  Human noroviruses are the most common cause of viral gastroenteritis worldwide and one of the leading causes of viral diarrhea in children under the age of 5 years. Hands have been shown to play an important role in norovirus transmission. Norovirus outbreaks tend to exhibit strong seasonality, most often occurring during cold, dry months, but recently have also been documented during hot, dry winter months in the southern hemisphere. Other research suggests that rainfall is an important factor in norovirus outbreaks. This study examines the prevalence and concentration of human norovirus GII on the hands of mothers in Bagamoyo, Tanzania, during the rainy and dry seasons. Norovirus GII was detected in approximately 5% of hand rinse samples during both the rainy and dry seasons. Fecal indicator bacteria levels, Escherichia coli and enterococci, in hand rinse samples were not associated with norovirus hand contamination. Turbidity of the hand rinses was found to be associated with norovirus presence on mothers' hands; however, this relationship was only observed during the rainy season. The results suggest mothers' hands serve as a source of norovirus exposure for young children in Tanzanian households, and further work is needed to determine better indicators of norovirus contamination in these environments.

  View details for DOI 10.4269/ajtmh.14-0778

  View details for PubMedID 26149861

  View details for PubMedCentralID PMC4559683

• Container-based sanitation: assessing costs and effectiveness of excreta management in Cap Haitien, Haiti ENVIRONMENT AND URBANIZATION Tilmans, S., Russel, K., Sklar, R., Page, L., Kramer, S., Davis, J. 2015; 27 (1): 89-104

  View details for DOI 10.1177/0956247815572746

  View details for Web of Science ID 000352979200006

• Hand-to-Mouth Contacts Result in Greater Ingestion of Feces than Dietary Water Consumption in Tanzania: A Quantitative Fecal Exposure Assessment Model. Environmental science & technology Mattioli, M. C., Davis, J., Boehm, A. B. 2015; 49 (3): 1912-1920

  Abstract

  Diarrheal diseases kill 1800 children under the age of five die each day, and nearly half of these deaths occur in sub-Saharan Africa. Contaminated drinking water and hands are two important environmental transmission routes of diarrhea-causing pathogens to young children in low-income countries. The objective of this research is to evaluate the relative contribution of these two major exposure pathways in a low-income country setting. A Monte Carlo simulation was used to model the amount of human feces ingested by children under five years old from exposure via hand-to-mouth contacts and stored drinking water ingestion in Bagamoyo, Tanzania. Child specific exposure data were obtained from the USEPA 2011 Exposure Factors Handbook, and fecal contamination was estimated using hand rinse and stored water fecal indicator bacteria concentrations from over 1200 Tanzanian households. The model outcome is a distribution of a child's daily dose of feces via each exposure route. The model results show that Tanzanian children ingest a significantly greater amount of feces each day from hand-to-mouth contacts than from drinking water, which may help elucidate why interventions focused on water without also addressing hygiene often see little to no effect on reported incidence of diarrhea.

  View details for DOI 10.1021/es505555f

  View details for PubMedID 25559008

• Health and development at the food-water nexus The Evolving Sphere of Food Security Davis, J., Bendavid, E., Pickering, A., Naylor , R. edited by Naylor , R. Oxford University Press. 2015
• Differences in field effectiveness and adoption between a novel automated chlorination system and household manual chlorination of drinking water in Dhaka, Bangladesh: a randomized controlled trial. PloS one Pickering, A. J., Crider, Y., Amin, N., Bauza, V., Unicomb, L., Davis, J., Luby, S. P. 2015; 10 (3)

  Abstract

  The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically) dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab), safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities.

  View details for DOI 10.1371/journal.pone.0118397

  View details for PubMedID 25734448

  View details for PubMedCentralID PMC4348460

• Community Participation and Water Supply Sustainability: Evidence from Handpump Projects in Rural Ghana JOURNAL OF PLANNING EDUCATION AND RESEARCH Marks, S. J., Komives, K., Davis, J. 2014; 34 (3): 276–86

  View details for DOI 10.1177/0739456X14527620

  View details for Web of Science ID 000340944800002

• Exploring the link between the productive use of rural piped water and system sustainability in Senegal Water Alternatives Hall, R. P., Vance, E., van Houweling , E., Davis, J. 2014; 7 (3): 480-498
• The challenge of global water access monitoring: evaluating straight-line distance versus self-reported travel time among rural households in Mozambique JOURNAL OF WATER AND HEALTH Ho, J. C., Russel, K. C., Davis, J. 2014; 12 (1): 173-183

  Abstract

  Support is growing for the incorporation of fetching time and/or distance considerations in the definition of access to improved water supply used for global monitoring. Current efforts typically rely on self-reported distance and/or travel time data that have been shown to be unreliable. To date, however, there has been no head-to-head comparison of such indicators with other possible distance/time metrics. This study provides such a comparison. We examine the association between both straight-line distance and self-reported one-way travel time with measured route distances to water sources for 1,103 households in Nampula province, Mozambique. We find straight-line, or Euclidean, distance to be a good proxy for route distance (R(2) = 0.98), while self-reported travel time is a poor proxy (R(2) = 0.12). We also apply a variety of time- and distance-based indicators proposed in the literature to our sample data, finding that the share of households classified as having versus lacking access would differ by more than 70 percentage points depending on the particular indicator employed. This work highlights the importance of the ongoing debate regarding valid, reliable, and feasible strategies for monitoring progress in the provision of improved water supply services.

  View details for DOI 10.2166/wh.2013.042

  View details for Web of Science ID 000338511500017

• Video surveillance captures student hand hygiene behavior, reactivity to observation, and peer influence in kenyan primary schools. PloS one Pickering, A. J., Blum, A. G., Breiman, R. F., Ram, P. K., Davis, J. 2014; 9 (3)

  Abstract

  In-person structured observation is considered the best approach for measuring hand hygiene behavior, yet is expensive, time consuming, and may alter behavior. Video surveillance could be a useful tool for objectively monitoring hand hygiene behavior if validated against current methods.Student hand cleaning behavior was monitored with video surveillance and in-person structured observation, both simultaneously and separately, at four primary schools in urban Kenya over a study period of 8 weeks.Video surveillance and in-person observation captured similar rates of hand cleaning (absolute difference <5%, p = 0.74). Video surveillance documented higher hand cleaning rates (71%) when at least one other person was present at the hand cleaning station, compared to when a student was alone (48%; rate ratio  = 1.14 [95% CI 1.01-1.28]). Students increased hand cleaning rates during simultaneous video and in-person monitoring as compared to single-method monitoring, suggesting reactivity to each method of monitoring. This trend was documented at schools receiving a handwashing with soap intervention, but not at schools receiving a sanitizer intervention.Video surveillance of hand hygiene behavior yields results comparable to in-person observation among schools in a resource-constrained setting. Video surveillance also has certain advantages over in-person observation, including rapid data processing and the capability to capture new behavioral insights. Peer influence can significantly improve student hand cleaning behavior and, when possible, should be exploited in the design and implementation of school hand hygiene programs.

  View details for DOI 10.1371/journal.pone.0092571

  View details for PubMedID 24676389

  View details for PubMedCentralID PMC3968003

• The potential for financing small-scale wastewater treatment through resource recovery: experience from Bocas del Toro, Panama JOURNAL OF WATER SANITATION AND HYGIENE FOR DEVELOPMENT Tilmans, S., Diaz-Hernandez, A., Nyman, E., Davis, J. 2014; 4 (3): 449-459

  View details for DOI 10.2166/washdev.2014.138

  View details for Web of Science ID 000341563800011

• The entrepreneurship myth in small-scale service provision: Water resale in Maputo, Mozambique JOURNAL OF WATER SANITATION AND HYGIENE FOR DEVELOPMENT Zuin, V., Ortolano, L., Davis, J. 2014; 4 (2): 281-292

  View details for DOI 10.2166/washdev.2013.065

  View details for Web of Science ID 000341563300011

• Site fights: Explaining variation in opposition to pipeline projects in the developing world Megaproject Planning and Management: Essential Readings McAdam, D., Schafer, H., Davis, J., Orr, R. edited by Elgar, E. Cheltenham, UK and Northampton, MA. 2014
• Access to waterless hand sanitizer improves student hand hygiene behavior in primary schools in nairobi, kenya. American journal of tropical medicine and hygiene Pickering, A. J., Davis, J., Blum, A. G., Scalmanini, J., Oyier, B., Okoth, G., Breiman, R. F., Ram, P. K. 2013; 89 (3): 411-418

  Abstract

  Handwashing is difficult in settings with limited resources and water access. In primary schools within urban Kibera, Kenya, we investigated the impact of providing waterless hand sanitizer on student hand hygiene behavior. Two schools received a waterless hand sanitizer intervention, two schools received a handwashing with soap intervention, and two schools received no intervention. Hand cleaning after toileting was 82% at sanitizer schools (N = 2,507 events), 38% at soap schools (N = 3,429), and 37% at control schools (N = 2,797), which was measured by structured observation over 2 months. Students at sanitizer schools were 23% less likely to have observed rhinorrhea than control students (P = 0.02); reductions in student-reported gastrointestinal and respiratory illness symptoms were not statistically significant. Providing waterless hand sanitizer markedly increased student hand cleaning after toilet use, whereas the soap intervention did not. Waterless hand sanitizer may be a promising option to improve student hand cleansing behavior, particularly in schools with limited water access.

  View details for DOI 10.4269/ajtmh.13-0008

  View details for PubMedID 23836575

• Hands and Water as Vectors of Diarrhea! Pathogens in Bagannoyo, Tanzania ENVIRONMENTAL SCIENCE & TECHNOLOGY Mattioli, M. C., Pickering, A. J., Gilsdorf, R. J., Davis, J., Boehm, A. B. 2013; 47 (1): 355-363

  Abstract

  Diarrheal disease is a leading cause of under-five childhood mortality worldwide, with at least half of these deaths occurring in sub-Saharan Africa. Transmission of diarrheal pathogens occurs through several exposure routes including drinking water and hands, but the relative importance of each route is not well understood. Using molecular methods, this study examines the relative importance of different exposure routes by measuring enteric bacteria (pathogenic Escherichia coli) and viruses (rotavirus, enterovirus, adenovirus) in hand rinses, stored water, and source waters in Bagamoyo, Tanzania. Viruses were most frequently found on hands, suggesting that hands are important vectors for viral illness. The occurrence of E. coli virulence genes (ECVG) was equivalent across all sample types, indicating that both water and hands are important for bacterial pathogen transmission. Fecal indicator bacteria and turbidity were good predictors of ECVG, whereas turbidity and human-specific Bacteroidales were good predictors of viruses. ECVG were more likely found in unimproved water sources, but both ECVG and viral genes were detected in improved water sources. ECVG were more likely found in stored water of households with unimproved sanitation facilities. The results provide insights into the distribution of pathogens in Tanzanian households and offer evidence that hand-washing and improved water management practices could alleviate viral and bacterial diarrhea.

  View details for DOI 10.1021/es303878d

  View details for Web of Science ID 000313220300046

  View details for PubMedID 23181394

• Mechanisms of post-supply contamination of drinking water in Bagamoyo Tanzania. Journal of Water & Health Harris, A., R., Davis, J., Boehm, A., B. 2013; 3 (11): 543-54

  Abstract

  Access to household water connections remains low in sub-Saharan Africa, representing a public health concern. Previous studies have shown water stored in the home to be more contaminated than water at the source; however, the mechanisms of post-supply contamination remain unclear. Using water quality measurements and structured observations of households in Bagamoyo, Tanzania, this study elucidates the causal mechanisms of the microbial contamination of drinking water after collection from a communal water source. The study identifies statistically significant loadings of fecal indicator bacteria (FIB) occurring immediately after filling the storage container at the source and after extraction of the water from the container in the home. Statistically significant loadings of FIB also occur with various water extraction methods, including decanting from the container and use of a cup or ladle. Additionally, pathogenic genes of Escherichia coli were detected in stored drinking water but not in the source from which it was collected, highlighting the potential health risks of post-supply contamination. The results of the study confirm that storage containers and extraction utensils introduce microbial contamination into stored drinking water, and suggest that further research is needed to identify methods of water extraction that prevent microbial contamination of drinking water.

  View details for DOI 10.2166/wh.2013.023

• Enteric pathogens in stored drinking water and on caregiver's hands in Tanzanian households with and without reported cases of child diarrhea PLOS One Mattioli, M., Boehm, A., B., Davis, J., Harris, A., Mrisho, M., Pickering, A., J. 2013; 1 (9): e84939

  View details for DOI 10.1371/journal.pone.0084939

• Does sense of ownership matter for rural water system sustainability? Evidence from Kenya Journal of Water, Sanitation, and Hygiene for Development Marks, S., Onda, K., Davis, J. 2013; 2 (3): 122–133

  View details for DOI 10.2166/washdev.2013.098

• Socioeconomic and environmental impacts of domestic bio-digesters: Evidence from Arusha, Tanzania Energy for Sustainable Development Laramee, J., Davis, J. 2013

  View details for DOI 10.1016/j.esd.2013.02.001

• Does User Participation Lead to Sense of Ownership for Rural Water Systems? Evidence from Kenya WORLD DEVELOPMENT Marks, S. J., Davis, J. 2012; 40 (8): 1569-1576

  View details for DOI 10.1016/j.worlddev.2012.03.011

  View details for Web of Science ID 000306028400007

• Fecal Contamination and Diarrheal Pathogens on Surfaces and in Soils among Tanzanian Households with and without Improved Sanitation ENVIRONMENTAL SCIENCE & TECHNOLOGY Pickering, A. J., Julian, T. R., Marks, S. J., Mattioli, M. C., Boehm, A. B., Schwab, K. J., Davis, J. 2012; 46 (11): 5736-5743

  Abstract

  Little is known about the extent or pattern of environmental fecal contamination among households using low-cost, on-site sanitation facilities, or what role environmental contamination plays in the transmission of diarrheal disease. A microbial survey of fecal contamination and selected diarrheal pathogens in soil (n = 200), surface (n = 120), and produce samples (n = 24) was conducted in peri-urban Bagamoyo, Tanzania, among 20 households using private pit latrines. All samples were analyzed for E. coli and enterococci. A subset was analyzed for enterovirus, rotavirus, norovirus GI, norovirus GII, diarrheagenic E. coli, and general and human-specific Bacteroidales fecal markers using molecular methods. Soil collected from the house floor had significantly higher concentrations of E. coli and enterococci than soil collected from the latrine floor. There was no significant difference in fecal indicator bacteria levels between households using pit latrines with a concrete slab (improved sanitation) versus those without a slab. These findings imply that the presence of a concrete slab does not affect the level of fecal contamination in the household environment in this setting. Human Bacteroidales, pathogenic E. coli, enterovirus, and rotavirus genes were detected in soil samples, suggesting that soil should be given more attention as a transmission pathway of diarrheal illness in low-income countries.

  View details for DOI 10.1021/es300022c

  View details for Web of Science ID 000304783000017

  View details for PubMedID 22545817

• Freshwater Availability and Water Fetching Distance Affect Child Health in Sub-Saharan Africa ENVIRONMENTAL SCIENCE & TECHNOLOGY Pickering, A. J., Davis, J. 2012; 46 (4): 2391-2397

  Abstract

  Currently, more than two-thirds of the population in Africa must leave their home to fetch water for drinking and domestic use. The time burden of water fetching has been suggested to influence the volume of water collected by households as well as time spent on income generating activities and child care. However, little is known about the potential health benefits of reducing water fetching distances. Data from almost 200, 000 Demographic and Health Surveys carried out in 26 countries were used to assess the relationship between household walk time to water source and child health outcomes. To estimate the causal effect of decreased water fetching time on health, geographic variation in freshwater availability was employed as an instrumental variable for one-way walk time to water source in a two-stage regression model. Time spent walking to a household's main water source was found to be a significant determinant of under-five child health. A 15-min decrease in one-way walk time to water source is associated with a 41% average relative reduction in diarrhea prevalence, improved anthropometric indicators of child nutritional status, and a 11% relative reduction in under-five child mortality. These results suggest that reducing the time cost of fetching water should be a priority for water infrastructure investments in Africa.

  View details for DOI 10.1021/es203177v

  View details for Web of Science ID 000300465900056

  View details for PubMedID 22242546

• Freshwater availability affects child health in sub-Saharan Africa Environmental Science & Technology Pickering, A., Davis, J. 2012

  View details for DOI 10.1021/es203177v

• The role of productive water use in women's livelihoods: Evidence from rural Senegal Water Alternatives Houweling, E., van, Hall, R., Diop, A., S., Davis, J., Seiss, M. 2012; 3 (5): 658-677
• Water supply services for Africa's urban poor: the role of resale JOURNAL OF WATER AND HEALTH Zuin, V., Ortolano, L., Alvarinho, M., Russel, K., Thebo, A., Muximpua, O., Davis, J. 2011; 9 (4): 773-784

  Abstract

  In sub-Saharan Africa only 35% of the urban population has access to a piped water connection on their premises. The majority of households obtain water from public standpipes or from neighbors who are connected to the municipal network. Water resale is often prohibited, however, because of concerns about affordability and risks to public health. Using data collected from 1,377 households in Maputo, Mozambique, we compare the microbiological quality, as well as the time and money costs of water supply from individual house connections, public standpipes, and water obtained from neighbors. Households with their own water connections have better service across virtually all indicators measured, and express greater satisfaction with their service, as compared with those using other water sources. Households purchasing water from their neighbors pay lower time and money costs per liter of water, on average, as compared with those using standpipes. Resale competes favorably with standpipes along a number of service quality dimensions; however, after controlling for water supply characteristics, households purchasing water from neighbors are significantly less likely to be satisfied with their water service as compared with those using standpipes.

  View details for DOI 10.2166/wh.2011.031

  View details for Web of Science ID 000297599300016

  View details for PubMedID 22048436

• Increasing the Role of Economics in Environmental Research (or Moving beyond the Mindset That Economics = Accounting) ENVIRONMENTAL SCIENCE & TECHNOLOGY Characklis, G. W., Adriaens, P., Braden, J. B., Davis, J., Hamilton, B., Hughes, J. B., Small, M. J., Wolfe, J. 2011; 45 (15): 6235-6236

  View details for DOI 10.1021/es202128s

  View details for Web of Science ID 000293196400007

  View details for PubMedID 21740005

• Drivers of Conflict in Developing Country Infrastructure Projects: Experience from the Water and Pipeline Sectors JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT-ASCE Boudet, H. S., Jayasundera, D. C., Davis, J. 2011; 137 (7): 498-511

  View details for DOI 10.1061/(ASCE)CO.1943-7862.0000333

  View details for Web of Science ID 000292516700004

• The Effects of Informational Interventions on Household Water Management, Hygiene Behaviors, Stored Drinking Water Quality, and Hand Contamination in Peri-Urban Tanzania AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE Davis, J., Pickering, A. J., Rogers, K., Mamuya, S., Boehm, A. B. 2011; 84 (2): 184-191

  Abstract

  Safe water storage and hand hygiene have been shown to reduce fecal contamination and improve health in experimental settings; however, triggering and sustaining such behaviors is challenging. This study investigates the extent to which personalized information about Escherichia coli contamination of stored water and hands influenced knowledge, reported behaviors, and subsequent contamination levels among 334 households with less than 5-year-old children in peri-urban Dar es Salaam, Tanzania. One-quarter of the study participants received information about strategies to reduce risk of water- and sanitation-related illness. Respondents in another three study cohorts received this same information, along with their household's water and/or hand-rinse test results. Findings from this study suggest that additional work is needed to elucidate the conditions under which such testing represents a cost-effective strategy to motivate improved household water management and hand hygiene.

  View details for DOI 10.4269/ajtmh.2011.10-0126

  View details for Web of Science ID 000287003900002

  View details for PubMedID 21292883

  View details for PubMedCentralID PMC3029166

• Efficacy of alcohol-based hand sanitizer on hands soiled with dirt and cooking oil JOURNAL OF WATER AND HEALTH Pickering, A. J., Davis, J., Boehm, A. B. 2011; 9 (3): 429-433

  Abstract

  Handwashing education and promotion are well established as effective strategies to reduce diarrhea and respiratory illness in countries around the world. However, access to reliable water supplies has been identified as an important barrier to regular handwashing in low-income countries. Alcohol-based hand sanitizer (ABHS) is an effective hand hygiene method that does not require water, but its use is not currently recommended when hands are visibly soiled. This study evaluated the efficacy of ABHS on volunteers' hands artificially contaminated with Escherichia coli in the presence of dirt (soil from Tanzania) and cooking oil. ABHS reduced levels of E. coli by a mean of 2.33 log colony forming units (CFU) per clean hand, 2.32 log CFU per dirt-covered hand, and 2.13 log CFU per oil-coated hand. No significant difference in efficacy was detected between hands that were clean versus dirty or oily. ABHS may be an appropriate hand hygiene method for hands that are moderately soiled, and an attractive option for field settings in which access to water and soap is limited.

  View details for DOI 10.2166/wh.2011.138

  View details for Web of Science ID 000293624300001

  View details for PubMedID 21976190

• Site fights Global Projects McAdam, D., Schaffer Boudet, H., Davis, J., Orr, Ryan, J., Scott, W., Richard, Levitt, Raymond, E. edited by Scott, W. R., Levitt, R. E., Orr, R. J. Cambridge, UK: Cambridge University Press. 2011
• Water resale to neighbors in Maputo, Mozambique: costs, service quality, and user satisfaction Journal of Water and Health Zuin, V., Ortolano, L., Alvarinho, M., Russel, K., Thebo, A., Muximpua, O., Davis, J. 2011; 9 (4): 773-784

  View details for DOI 10.2166/wh.2011.031

• Drivers of conflict in global infrastructure projects: Experience from the water and pipeline sectors Journal of Construction Engineering and Managemen Schaffer-Boude, H., Jayasundera, D., C., Davis, J. 2011; 7 (137): 498-511

  View details for DOI 10.1061/(ASCE)CO.1943-7862.0000333

• Understanding Household Behavioral Risk Factors for Diarrheal Disease in Dar es Salaam: A Photovoice Community Assessment Journal of Environmental and Public Health Badowski, N., Castro, C., Montgomery, M., Pickering, A., Mamuya, S., Davis, J. 2011

  View details for DOI 10.1155/2011/130467

• "Site Fights": Explaining Opposition to Pipeline Projects in the Developing World1 SOCIOLOGICAL FORUM McAdam, D., Boudet, H. S., Davis, J., Orr, R. J., Scott, W. R., Levitt, R. E. 2010; 25 (3): 401-427

  View details for DOI 10.1111/j.1573-7861.2010.01189.x

  View details for Web of Science ID 000280638000001

• Hands, Water, and Health: Fecal Contamination in Tanzanian Communities with Improved, Non-Networked Water Supplies ENVIRONMENTAL SCIENCE & TECHNOLOGY Pickering, A. J., Davis, J., Walters, S. P., Horak, H. M., Keymer, D. P., Mushi, D., Strickfaden, B., Chynoweth, J. S., Liu, J., Blum, A., Rogers, K., Boehm, A. B. 2010; 44 (9): 3267-3272

  Abstract

  Almost half of the world's population relies on non-networked water supply services, which necessitates in-home water storage. It has been suggested that dirty hands play a role in microbial contamination of drinking water during collection, transport, and storage. However, little work has been done to evaluate quantitatively the association between hand contamination and stored water quality within households. This study measured levels of E. coli, fecal streptococci, and occurrence of the general Bacteroidales fecal DNA marker in source water, in stored water, and on hands in 334 households among communities in Dar es Salaam, Tanzania, where residents use non-networked water sources. Levels of fecal contamination on hands of mothers and children were positively correlated to fecal contamination in stored drinking water within households. Household characteristics associated with hand contamination included mother's educational attainment, use of an improved toilet, an infant in the household, and dissatisfaction with the quantity of water available for hygiene. In addition, fecal contamination on hands was associated with the prevalence of gastrointestinal and respiratory symptoms within a household. The results suggest that reducing fecal contamination on hands should be investigated as a strategy for improving stored drinking water quality and health among households using non-networked water supplies.

  View details for DOI 10.1021/es903524m

  View details for Web of Science ID 000277067000014

  View details for PubMedID 20222746

• Efficacy of Waterless Hand Hygiene Compared with Handwashing with Soap: A Field Study in Dar es Salaam, Tanzania AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE Pickering, A. J., Boehm, A. B., Mwanjali, M., Davis, J. 2010; 82 (2): 270-278

  Abstract

  Effective handwashing with soap requires reliable access to water supplies. However, more than three billion persons do not have household-level access to piped water. This research addresses the challenge of improving hand hygiene within water-constrained environments. The antimicrobial efficacy of alcohol-based hand sanitizer, a waterless hand hygiene product, was evaluated and compared with handwashing with soap and water in field conditions in Dar es Salaam, Tanzania. Hand sanitizer use by mothers resulted in 0.66 and 0.64 log reductions per hand of Escherichia coli and fecal streptococci, respectively. In comparison, handwashing with soap resulted in 0.50 and 0.25 log reductions per hand of E. coli and fecal streptococci, respectively. Hand sanitizer was significantly better than handwashing with respect to reduction in levels of fecal streptococci (P = 0.01). The feasibility and health impacts of promoting hand sanitizer as an alternative hand hygiene option for water-constrained environments should be assessed.

  View details for DOI 10.4269/ajtmh.2010.09-0220

  View details for Web of Science ID 000274263300018

  View details for PubMedID 20134005

  View details for PubMedCentralID PMC2813169

• Bacterial hand contamination among Tanzanian mothers varies temporally and following household activities Tropical Medicine & International Health Pickering, A., Julian, T., Boehm, A., Davis, J. 2010

  View details for DOI 10.1111/j.1365-3156.2010.02677.x

• Microbial and metal water quality in rain catchments compared with traditional drinking water sources in the East Sepik Province, Papua New Guinea JOURNAL OF WATER AND HEALTH Horak, H. M., Chynoweth, J. S., Myers, W. P., Davis, J., Fendorf, S., Boehm, A. B. 2010; 8 (1): 126-138

  Abstract

  In Papua New Guinea, a significant portion of morbidity and mortality is attributed to water-borne diseases. To reduce incidence of disease, communities and non-governmental organizations have installed rain catchments to provide drinking water of improved quality. However, little work has been done to determine whether these rain catchments provide drinking water of better quality than traditional drinking water sources, and if morbidity is decreased in villages with rain catchments. The specific aim of this study was to evaluate the quality of water produced by rain catchments in comparison with traditional drinking water sources in rural villages in the East Sepik Province. Fifty-four water sources in 22 villages were evaluated for enterococci and Escherichia coli densities as well as 14 health-relevant metals. In addition, we examined how the prevalence of diarrhoeal illness in villages relates to the type of primary drinking water source. The majority of tested metals were below World Health Organization safety limits. Catchment water sources had lower enterococci and E. coli than other water sources. Individuals in villages using Sepik River water as their primary water source had significantly higher incidence of diarrhoea than those primarily using other water sources (streams, dug wells and catchments).

  View details for Web of Science ID 000275310700014

  View details for PubMedID 20009255

• Water quality of water in rain catchments compared to other drinking water sources in the East Sepik Province, Papua New Guinea Journal of Water and Health Horak, H., M., Chynoweth, J., S., Myers, W., P., Davis, J., A., Fendorf, S., Boehm, A., B. 2010; 8: 126-138
• Explaining variation in opposition to pipeline projects in the developing world Environmental Politics McAdam, D., Schafer, H., Davis, J., Orr, R. 2009; 2 (18): 307-308
• How well is the demand-driven, community management model for rural water supply systems doing? Evidence from Bolivia, Peru and Ghana WATER POLICY Whittington, D., Davis, J., Prokopy, L., Komives, K., Thorsten, R., Lukacs, H., Bakalian, A., Wakeman, W. 2009; 11 (6): 696-718

  View details for DOI 10.2166/wp.2009.310

  View details for Web of Science ID 000272199200004

• Sustaining the benefits of rural water supply investments: Experience from Bolivia Post-construction Support and Sustainability in Community-Managed Rural Water Supply: Case Studies in Peru, Bolivia, and Ghana Davis, J., Luckas, H., Jeuland, M., Soto, B., Lizarraga, G., Alvestegui, A. edited by Bakalian, A., Wakeman, W. Washington, DC: The World Bank. 2009
• The economic returns to water and sanitation investments Global Crises, Global Solutions: Costs and Benefits Davis, J. edited by Lomberg, B. Cambridge, UK: Cambridge University Press. 2009
• Sustaining the benefits of rural water supply investments: Experience from Cochabamba and Chuquisaca, Bolivia WATER RESOURCES RESEARCH Davis, J., Lukacs, H., Jeuland, M., Alvestegui, A., Soto, B., Lizarraga, G., Bakalian, A., Wakeman, W. 2008; 44 (12)

  View details for DOI 10.1029/2007WR006550

  View details for Web of Science ID 000261889600001

• Improving access to water supply and sanitation in urban India: microfinance for water and sanitation infrastructure development WATER SCIENCE AND TECHNOLOGY Davis, J., White, G., Damodaron, S., Thorsten, R. 2008; 58 (4): 887-891

  Abstract

  This article summarises initial findings of a study to explore the potential of providing micro-financing for low-income households wishing to invest in improved water supply and sanitation services. Through in-depth interviews with more than 800 households in the city of Hyderabad in India, we conclude that, even if provided with market (not concessional) rates of financing, a substantial proportion of poor households would invest in water and sewer network connections.

  View details for DOI 10.2166/wst.2008.671

  View details for Web of Science ID 000259176600019

  View details for PubMedID 18776626

• Sustaining the benefits of rural water supply investments: Experience from Bolivia Water Resources Research Davis, J., Luckas, H., Jeuland, M., Soto, B., Lizarraga, G. 2008; 44: W12427

  View details for DOI 10.1029/2007WR006550

• Private-sector Participation in the Water and Sanitation Sector Annual Review of Environment and Resources Davis, J. 2005; 30: 1-39
• Challenges for Water Sector Reform in Transition Economies Water Policy Davis, J., Whittington, D. 2004; 4 (6): 1-15
• Corruption in Public Services: Experience from South Asia’s Water and Sanitation Sector World Development Davis, J. 2003; 1 (32): 53-71
• Scaling Up Slum Upgrading Efforts: Where are the Bottlenecks? International Development Planning Review Davis, J. 2003; 3 (26): 301-319
• Assessing Community Preferences for Development Initiatives: Are Willingness-to-pay Studies Robust to Mode Effects? World Development Davis, J. 2002; 4 (32): 655-672
• Implementing a Demand-driven Approach to Community Water Supply Planning: A Case Study of Lugazi, Uganda Water Resources and Economic Development, Cheltenham Whittington, D., Davis, J., McClelland, E. edited by Saleth, R. M. UK: Edward Elgar Publishing. 2002
• How Important is Improved Water Infrastructure to Microenterprises? Evidence from Uganda World Development  Davis, J., Kang, A., Vincent, J., Whittington, D. 2001; 10 (29): 1753-1767
• Designing a “Neighborhood Deal” for Urban Sewers: A Case Study of Semarang, Indonesia Journal of Planning Education and Research Whittington, D., Davis, J., Miarsono, H., Pollard, R. 1999; 3 (19): 297-308
• Implementing a Demand-driven Approach to Community Water Supply Planning: A Case Study of Lugazi, Uganda Water International Whittington, D., Davis, J., McClelland, E. 1999; 3 (23): 134-145
• Participatory Research Techniques for Development Projects: A Comparison of the Contingent Valuation and Community Dialogue methods Economic Development and Cultural Change Davis, J., Whittington, D. 1998; 1 (47): 73-81