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Background and Objectives: This qualitative study explored perceived community strengths and health issues among 3 underserved and under-studied populations in the Atlanta, Georgia-older adults, Black or African American persons, and refugees/immigrants/migrants., Methods: Eight focus groups were conducted with 92 participants who were members of the 3 populations in Atlanta between November 2022 and March 2023., Results: Although there were variations among groups, all groups emphasized diversity within their community as the foundation of community strength. Elements of the built environment such as parks, convenience stores, the Atlanta Beltline, and food outlets bolstered community strength. Furthermore, community members being able to voice concerns and the responsiveness of governmental institutions helped form strong relationships to build a strong community. Regarding health issues, common physical health concerns included hypertension and obesity, with varied mental health issues. Accessibility and affordability of healthy foods were significant social concerns, alongside challenges in healthcare access such as navigating complex systems and high medical costs., Conclusion: Tailored interventions recognizing community strengths and addressing specific health issues are crucial for improving outcomes in marginalized communities, necessitating a health-in-all policies approach considering social, cultural, and structural determinants of health., Competing Interests: The authors declare no conflict of interest., (Copyright © 2025 The Authors. Published by Wolters Kluwer Health, Inc.)

Background: Aspirin is frequently utilized for antiplatelet therapy in children with congenital heart disease (CHD). Patients who are unresponsive to aspirin, as measured by aspirin reaction units (ARU), are at higher risk for thrombotic events. It is undetermined if dose modification of aspirin results in adequate responsiveness in these patients. This study evaluates the prevalence and risk factors for aspirin nonresponsiveness and the results of dose escalation in this population., Methods: This is a retrospective review of patients cared for in the cardiac care unit at a quaternary care academic congenital heart center who received aspirin and had responsiveness evaluated between January 2018 and January 2023. Patient demographics and clinical characteristics were extracted from the medical record. Descriptive, parametric, and nonparametric univariate analysis were employed., Results: A total of 142 patients (69 [49%] female, 45 [32%]Non-Hispanic White, and 63 [44%] Hispanic]) were identified. Median age at first aspirin responsiveness assessment was 54 [interquartile range, IQR: 23.3-411.5] days with a median weight of 5.2 [IQR: 3.64-9.29] kg. Of these, 32/142 (22.5%) were nonresponsive on their initial testing. Of these patients, 23/32 (72%) had follow-up testing with 19/23 (83%) subsequently becoming therapeutic. This was achieved with an increased dose in 12/19 (63%) patients and increased duration of therapy in 7/19 (37%) patients. Seventeen of 142 (12%) patients experienced a thrombotic event, 13/17 (77%) of which were therapeutic on initial responsiveness assessment., Conclusions: It is common for CHD patients to be aspirin nonresponsive with initial weight-based dosing. If aspirin is used in this population, it is necessary to evaluate ARUs on all patients as underdosing is not uncommon with current weight-based dosing methods., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

During the 2015-2016 Zika virus (ZIKV) epidemic in the Americas, serological cross-reactivity with other flaviviruses and relatively high costs of nucleic acid testing in the region hindered the capacity for widespread diagnostic testing. In such cases where individual testing is not feasible, wastewater monitoring approaches may offer a means of community-level public health surveillance. To inform such approaches, we characterized the persistence and recovery of ZIKV RNA in experiments where we spiked cultured ZIKV into surface water, wastewater, and a combination of both to examine the potential for detection in open sewers serving communities most affected by the ZIKV outbreak, such as those in Salvador, Bahia, Brazil. We used reverse transcription droplet digital PCR to quantify ZIKV RNA. In our persistence experiments, we found that the persistence of ZIKV RNA decreased with increasing temperature, significantly decreased in surface water versus wastewater, and significantly decreased when the initial concentration of virus was lowered by one order of magnitude. In our recovery experiments, we found higher percent recovery of ZIKV RNA in pellets versus supernatants from the same sample, higher recoveries in pellets using skimmed milk flocculation, lower recoveries of ZIKV RNA in surface water versus wastewater, and lower recoveries from a freeze thaw. We also analyzed samples collected from Salvador, Brazil during the ZIKV outbreak (2015-2016) that consisted of archived samples obtained from open sewers or environmental waters thought to be contaminated by sewage. Although we did not detect any ZIKV RNA in the archived Brazil samples, results from these persistence and recovery experiments serve to inform future wastewater monitoring efforts in open sewers, an understudied and important application of wastewater monitoring., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Introduction: Leptospirosis is a globally distributed zoonotic and environmentally mediated disease that has emerged as a major health problem in urban slums in developing countries. Its aetiological agent is bacteria of the genus Leptospira , which are mainly spread in the urine of infected rodents, especially in an environment where adequate sanitation facilities are lacking, and it is known that open sewers are key transmission sources of the disease. Therefore, we aim to evaluate the effectiveness of a simplified sewerage intervention in reducing the risk of exposure to contaminated environments and Leptospira infection and to characterise the transmission mechanisms involved., Methods and Analysis: This matched quasi-experimental study design using non-randomised intervention and control clusters was designed to assess the effectiveness of an urban simplified sewerage intervention in the low-income communities of Salvador, Brazil. The intervention consists of household-level piped sewerage connections and community engagement and public involvement activities. A cohort of 1400 adult participants will be recruited and grouped into eight clusters consisting of four matched intervention-control pairs with approximately 175 individuals in each cluster in baseline. The primary outcome is the seroincidence of Leptospira infection assessed through five serological measurements: one preintervention (baseline) and four postintervention. As a secondary outcome, we will assess Leptospira load in soil, before and after the intervention. We will also assess Leptospira exposures before and after the intervention, through transmission modelling, accounting for residents' movement, contact with flooding, contaminated soil and water, and rat infestation, to examine whether and how routes of exposure for Leptospira change following the introduction of sanitation., Ethics and Dissemination: This study protocol has been reviewed and approved by the ethics boards at the Federal University of Bahia and the Brazilian National Research Ethics Committee. Results will be disseminated through peer-reviewed publications and presentations to implementers, researchers and participating communities., Trial Registration Number: Brazilian Clinical Trials Registry (RBR-8cjjpgm)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

An end goal of fecal source tracking (FST) is to provide information on risk of transmission of waterborne illnesses associated with fecal contamination. Ideally, concentrations of FST markers in ambient waters would reflect exposure risk. Human mtDNA is an FST marker that is exclusively human in origin and may be elevated in feces of individuals experiencing gastrointestinal inflammation. In this study, we examined whether human mtDNA is elevated in fecal samples from individuals with symptomatic norovirus infections using samples from the United States (US), Mozambique, and Bangladesh. We quantified hCYTB484 (human mtDNA) and HF183/BacR287 (human-associated Bacteroides ) FST markers using droplet digital polymerase chain reaction. We observed the greatest difference in concentrations of hCYTB484 when comparing samples from individuals with symptomatic norovirus infections versus individuals without norovirus infections or diarrhea symptoms: log 10 increase of 1.42 in US samples (3,820% increase, p -value = 0.062), 0.49 in Mozambique (308% increase, p -value = 0.061), and 0.86 in Bangladesh (648% increase, p -value = 0.035). We did not observe any trends in concentrations of HF183/BacR287 in the same samples. These results suggest concentrations of fecal mtDNA may increase during symptomatic norovirus infection and that mtDNA in environmental samples may represent an unambiguously human source-tracking marker that correlates with enteric pathogen exposure risk., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Despite multiple studies demonstrating the effectiveness of household water treatment with chlorine in disinfecting water and preventing diarrhea, social marketing of this intervention in low- and middle-income countries has resulted in only modest uptake. In a cluster randomized trial in Vihiga district, western Kenya, we compared uptake of household water treatment with chlorine among six villages served by community vendors trained in standard social marketing plus education through listening (ETL), an innovative behavior change method, and six villages served by community vendors trained in standard social marketing only. Water treatment uptake, water quality, and childhood diarrhea were measured over 6 months and compared between the two groups of villages. During the 6-month period, we found no association between ETL exposure and reported and confirmed household water treatment with chlorine. In both groups (ETL and comparison), reported use of water treatment was low and did not change during our 6-month follow-up. However, persons confirmed to have chlorinated water had improved bacteriologic water quality. Study findings suggest that ETL implementation was suboptimal, which, along with unexpected changes in the supply and price of chlorine, may have prevented an accurate assessment of the potential impact of ETL on water treatment behavior. Taken together, these observations exemplify the complexities of habits, practices, attitudes, and external factors that can create challenging conditions for implementing behavioral interventions. As a consequence, in this trial, ETL had no measurable impact on water treatment behavior.

Turbidity reduction by coagulation-flocculation in drinking water reduces microbes and organic matter, increasing effectiveness of downstream treatment. Chitosan is a promising household water coagulant, but needs parameters for use. This study tested the effects of chitosan dose, molecular weight (MW), degree of deacetylation (DD), and functional groups on bentonite and kaolinite turbidity reduction in model household drinking water. Higher MW or DD produced greater reductions. Highest reductions were at doses 1 and 3 mg/L by MW >50,000 or >70% DD (residual turbidity <5 NTU). Higher doses did not necessarily continually increase reduction. For functional groups, 3 mg/L produced the highest reductions by lactate, acetate, and HCl, and lower reductions of kaolinite than bentonite. Doses where the point of zero charge was observed clustered around 3 mg/L. Chitosan reduced clay turbidity in water; effectiveness was influenced by dose, clay type, MW, DD, and functional groups. Reduction did not necessarily increase with MW. Bentonite had a broader effective dose range and higher reduction at the optimal dose than kaolinite. Chitosans with and without functional groups performed similarly. The best of the studied doses was 3 mg/L. Chitosans are promising for turbidity reduction in low-resource settings if combined with sedimentation and/or filtration.

Diarrheal illness, a common occurrence among people living with human immunodeficiency virus (PLHIV), is largely preventable through access to safe drinking water quality, sanitation, and hygiene (WASH) facilities. We examined WASH characteristics among households with and without HIV-positive residents enrolled in the Global Enteric Multicenter Study (GEMS) in rural Western Kenya. Using univariable logistic regression, we examined differences between HIV-positive and HIV-negative households in regard to WASH practices. Among HIV-positive households, we explored the relationship between the length of time knowing their HIV status and GEMS enrollment. No statistically significant differences were apparent in the WASH characteristics among HIV-positive and HIV-negative households. However, we found differences in the WASH characteristics among HIV-positive households who were aware of their HIV status ≥ 30 days before enrollment compared with HIV-positive households who found out their status < 30 days before enrollment or thereafter. Significantly more households aware of their HIV-positive status before enrollment reported treating their drinking water (odds ratio [OR] confidence interval [CI]: 2.34 [1.12, 4.86]) and using effective water treatment methods (OR [CI]: 9.6 [3.09, 29.86]), and had better drinking water storage practices. This suggests that within this region of Kenya, HIV programs are effective in promoting the importance of practicing positive WASH-related behaviors among PLHIV.

Diarrheal disease is a leading cause of death among young children worldwide. As rates of acute diarrhea (AD; 1-6 days duration) have decreased, persistent diarrhea (PD; > 14 days duration) accounts for a greater proportion of the diarrheal disease burden. We describe factors associated with the duration of moderate-to-severe diarrhea in Kenyan children < 5 years old enrolled in the Global Enteric Multicenter Study. We found 587 (58%) children experienced AD, 360 (35%) had prolonged acute diarrhea (ProAD; 7-13 days duration), and 73 (7%) had PD. We constructed a Cox proportional hazards model to identify factors associated with diarrheal duration. Risk factors independently associated with longer diarrheal duration included infection with Cryptosporidium (hazard ratio [HR]: 0.868, P = 0.035), using an unimproved drinking water source (HR: 0.87, P = 0.035), and being stunted at enrollment (HR: 0.026, P < 0.0001). Diarrheal illness of extended duration appears to be multifactorial; given its association with adverse health and development outcomes, effective strategies should be implemented to reduce the duration and severity of diarrheal illness. Effective treatments for Cryptosporidium should be identified, interventions to improve drinking water are imperative, and nutrition should be improved through exclusive breastfeeding in infants ≤ 6 months and appropriate continued feeding practices for ill children.

Progression of geographic disparities in social determinants of health is a global concern. Using an Urban Health Index (UHI) approach, we proposed a framework of examining the change of geographic disparities in social determinants in small areas. Using the City of Atlanta in Georgia (USA) as a case study, we standardized six census-based social determinant indicators in 2000 and in 2010, respectively, and calculated their geometric mean to assign each census tract a UHI value for 2000 and for 2010. We then evaluated the temporal change of the UHIs in relation to the demographic changes using spatial and statistical methods. We found that Atlanta experienced an improvement in social determinant status and a reduction of disparities in the 10 years. The areas that experienced improvement, however, underwent demographic changes as well. This analysis provides support for displacement, rather than improvement, as the underlying factor for apparent change in geographic disparities. Findings suggest the importance of local evaluation for future policies to reduce disparities in cities.

High summer temperatures in extratropical areas have an impact on the public's health, mainly through heat stress, high air pollution concentrations, and the transmission of tropical diseases. The purpose of this study is to examine the current characteristics of heat events and future projections of summer apparent temperature (AT)-and associated health concerns-throughout the southeastern United States. Synoptic climatology was used to assess the atmospheric characteristics of extreme heat days (EHDs) from 1979-2015. Ozone concentrations also were examined during EHDs. Trends in summer-season AT over the 37-year period and correlations between AT and atmospheric circulation were determined. Mid-century estimates of summer AT were calculated using downscaled data from an ensemble of global climate models. EHDs throughout the Southeast were characterized by ridging and anticyclones over the Southeast and the presence of moist tropical air masses. Exceedingly high ozone concentrations occurred on EHDs in the Atlanta area and throughout central North Carolina. While summer ATs did not increase significantly from 1979-2015, summer ATs are projected to increase substantially by mid-century, with most the Southeast having ATs similar to that of present-day southern Florida (i.e., a tropical climate). High ozone concentrations should continue to occur during future heat events. Large urban areas are expected to be the most affected by the future warming, resulting from intensifying and expanding urban heat islands, a large increase in heat-vulnerable populations, and climate conditions that will be highly suitable for tropical-disease transmission by the Aedes aegypti mosquito. This nexus of vulnerability creates the potential for heat-related morbidity and mortality, as well as the appearance of disease not previously seen in the region. These effects can be attenuated by policies that reduce urban heat (e.g., cool roofs and green roofs) and that improve infrastructure (e.g. emergency services, conditioned space).

While DeKalb County, Georgia, offers free radon screening for all eligible residents, portions of the county remain relatively under-sampled. This pilot study focused on 10% of the census tracts in the county with the lowest proportion of radon testing; most were in southern DeKalb County. In total, 217 households were recruited and homes were tested for indoor radon concentrations on the lowest livable floor over an eight-week period from March-May 2015. Tract-level characteristics were examined to understand the differences in socio-demographic and economic factors between the pilot study area and the rest of the county. The pilot study tracts had a higher proportion of African Americans compared to the rest of DeKalb County (82% versus 47%). Radon was detected above 11.1 Bq/m³ (0.3 pCi/L) in 73% of the indoor samples and 4% of samples were above 148 Bq/m³ (4 pCi/L). Having a basement was the strongest predictive factor for detectable and hazardous levels of radon. Radon screening can identify problems and spur homeowners to remediate but more research should be done to identify why screening rates vary across the county and how that varies with radon levels in homes to reduce radon exposure.

Household water treatment with chlorine can improve microbiological quality and reduce diarrhea. Chlorination is typically assessed using free chlorine residual (FCR), with a lower acceptable limit of 0.2 mg/L, however, accurate measurement of FCR is challenging with turbid water. To compare potential measures of adherence to treatment and water quality, we chlorinated recently-collected water in rural Kenyan households and measured total chlorine residual (TCR), FCR, oxidation reduction potential (ORP), and E. coli concentration over 72 h in clay and plastic containers. Results showed that 1) ORP served as a useful proxy for chlorination in plastic containers up to 24 h; 2) most stored water samples disinfected by chlorination remained significantly less contaminated than source water for up to 72 h, even in the absence of FCR; 3) TCR may be a useful proxy indicator of microbiologic water quality because it confirms previous chlorination and is associated with a lower risk of E. coli contamination compared to untreated source water; and 4) chlorination is more effective in plastic than clay containers presumably because of lower chlorine demand in plastic., (Published by Elsevier Ltd.)

Background: Community water supplies in underserved areas of the United States may be associated with increased microbiological contamination and risk of gastrointestinal disease. Microbial and health risks affecting such systems have not been systematically characterized outside outbreak investigations. The objective of the study was to evaluate associations between self-reported gastrointestinal illnesses (GII) and household-level water supply characteristics., Methods: We conducted a cross-sectional study of water quality, water supply characteristics, and GII in 906 households served by 14 small and medium-sized community water supplies in Alabama's underserved Black Belt region., Results: We identified associations between respondent-reported water supply interruption and any symptoms of GII (adjusted odds ratio (aOR): 3.01, 95% confidence interval (CI) = 1.65-5.49), as well as low water pressure and any symptoms of GII (aOR: 4.51, 95% CI = 2.55-7.97). We also identified associations between measured water quality such as lack of total chlorine and any symptoms of GII (aOR: 5.73, 95% CI = 1.09-30.1), and detection of E. coli in water samples and increased reports of vomiting (aOR: 5.01, 95% CI = 1.62-15.52) or diarrhea (aOR: 7.75, 95% CI = 2.06-29.15)., Conclusions: Increased self-reported GII was associated with key water system characteristics as measured at the point of sampling in a cross-sectional study of small and medium water systems in rural Alabama in 2012 suggesting that these water supplies can contribute to endemic gastro-intestinal disease risks. Future studies should focus on further characterizing and managing microbial risks in systems facing similar challenges.

The biosand filter (BSF) is an intermittently operated, household-scale slow sand filter for which little data are available on the effect of sand composition on treatment performance. Therefore, bench-scale columns were prepared according to the then-current (2006-2007) guidance on BSF design and run in parallel to conduct two microbial challenge experiments of eight-week duration. Triplicate columns were loaded with Accusand silica or crushed granite to compare virus and E. coli reduction performance. Bench-scale experiments provided confirmation that increased schmutzdecke growth, as indicated by decline in filtration rate, is the primary factor causing increased E. coli reductions of up to 5-log10. However, reductions of challenge viruses improved only modestly with increased schmutzdecke growth. Filter media type (Accusand silica vs. crushed granite) did not influence reduction of E. coli bacteria. The granite media without backwashing yielded superior virus reductions when compared to Accusand. However, for columns in which the granite media was first backwashed (to yield a more consistent distribution of grains and remove the finest size fraction), virus reductions were not significantly greater than in columns with Accusand media. It was postulated that a decline in surface area with backwashing decreased the sites and surface area available for virus sorption and/or biofilm growth and thus decreased the extent of virus reduction. Additionally, backwashing caused preferential flow paths and deviation from plug flow; backwashing is not part of standard BSF field preparation and is not recommended for BSF column studies. Overall, virus reductions were modest and did not meet the 5- or 3-log10 World Health Organization performance targets.

Although small, rural water supplies may present elevated microbial risks to consumers in some settings, characterizing exposures through representative point-of-consumption sampling is logistically challenging. In order to evaluate the usefulness of consumer self-reported data in predicting measured water quality and risk factors for contamination, we compared matched consumer interview data with point-of-survey, household water quality and pressure data for 910 households served by 14 small water systems in rural Alabama. Participating households completed one survey that included detailed feedback on two key areas of water service conditions: delivery conditions (intermittent service and low water pressure) and general aesthetic characteristics (taste, odor and color), providing five condition values. Microbial water samples were taken at the point-of-use (from kitchen faucets) and as-delivered from the distribution network (from outside flame-sterilized taps, if available), where pressure was also measured. Water samples were analyzed for free and total chlorine, pH, turbidity, and presence of total coliforms and Escherichia coli. Of the 910 households surveyed, 35% of participants reported experiencing low water pressure, 15% reported intermittent service, and almost 20% reported aesthetic problems (taste, odor or color). Consumer-reported low pressure was associated with lower gauge-measured pressure at taps. While total coliforms (TC) were detected in 17% of outside tap samples and 12% of samples from kitchen faucets, no reported water service conditions or aesthetic characteristics were associated with presence of TC. We conclude that consumer-reported data were of limited utility in predicting potential microbial risks associated with small water supplies in this setting, although consumer feedback on low pressure-a risk factor for contamination-may be relatively reliable and therefore useful in future monitoring efforts.

There is growing evidence that household water treatment interventions improve microbiological water quality and reduce diarrheal disease risk. Few studies have examined, however, the impact of water treatment interventions on household-level hygiene and sanitation. This study examined the association of four water and sanitation conditions (access to latrines, improved sanitation, improved water and the plastic biosand filter) on the levels of total coliforms and E. coli on existing and introduced toys during an on-going randomized controlled trial of the plastic biosand filter (plastic BSF). The following conditions were associated with decreased bacterial contamination on children's toys: access to a latrine, access to improved sanitation and access to the plastic BSF. Overall, compared to existing toys, introduced toys had significantly lower levels of both E. coli and total coliforms. Results suggest that levels of fecal indicator bacteria contamination on children's toys may be associated with access to improved water and sanitation conditions in the home. In addition, the fecal indicator bacteria levels on toys probably vary with duration in the household. Additional information on how these toys become contaminated is needed to determine the usefulness of toys as indicators or sentinels of water, sanitation and hygiene conditions, behaviors and risks.

A randomized controlled trial of the plastic BioSand filter (BSF) was performed in rural communities in Tamale (Ghana) to assess reductions in diarrheal disease and improvements in household drinking water quality. Few studies of household water filters have been performed in this region, where high drinking water turbidity can be a challenge for other household water treatment technologies. During the study, the longitudinal prevalence ratio for diarrhea comparing households that received the plastic BSF to households that did not receive it was 0.41 (95% confidence interval: 0.18, 0.92), suggesting an overall diarrheal disease reduction of 59% [corrected]. The plastic BSF achieved a geometric mean reduction of 97% and 67% for E. coli and turbidity, respectively. These results suggest the plastic BSF significantly improved drinking water quality and reduced diarrheal disease during the short trial in rural Tamale, Ghana. The results are similar to other trials of household drinking water treatment technologies.

Point of use drinking water treatment with the BioSand filter (BSF) allows people to treat their water in the home. The purpose of this research was to document the ability of the Hydraid plastic-housing BSF to reduce diarrheal disease in households who received a BSF in a randomized controlled trial. The trial of the Hydraid plastic-housing BSF was carried out in rural, mountainous communities in Copan, Honduras during April of 2008 to February of 2009. A logistic regression adjusting for clustering showed that the incidence of diarrheal disease in children under 5 years was reduced by approximately 45% (odds ratio = 0.55, 95% confidence interval = 0.28, 1.10) in households that had a BSF compared with those households without a BSF, but this finding fluctuated depending on season and was not statistically significant. Households with a BSF had significantly better drinking water quality regardless of water source or season.

About half of the rural population of Cambodia lacks access to improved water; an even higher percentage lacks access to latrines. More than 35,000 concrete BioSand Water filters (BSF) have been installed in the country. However, the concrete BSF takes time to produce and weighs hundreds of pounds. A plastic BSF has been developed but may not perform to the same benchmarks established by its predecessor. To evaluate plastic BSF performance and health impact, we performed a cluster randomized controlled trial in 13 communities including 189 households and 1147 participants in the Angk Snoul district of Kandal Province from May to December 2008. The results suggest that villages with plastic BSFs had significantly lower concentrations of E. coli in drinking water and lower diarrheal disease (incidence rate ratio 0.41, 95% confidence interval: 0.24-0.69) compared to control villages. As one of the first studies on the plastic BSF in Cambodia, these are important findings, especially in a setting where the concrete BSF has seen high rates of continued use years after installation. The study suggests the plastic BSF may play an important role in scaling up the distribution/implementation of the BSF, potentially improving water quality and health in the region.

The biosand filter (BSF) is a promising point of use (POU) technology for water treatment; however there has been little follow-up of initial implementation to assess sustainability. The purpose of this study was to examine continued use, performance, and sustainability of previously implemented concrete BSFs in Bonao, Dominican Republic. Of 328 households visited and interviewed, 90% of BSFs were still in use after approximately 1 year since installation. Water-quality improvement, measured by fecal indicator bacteria reduction, was found to be 84-88%, which is lower than reductions in controlled laboratory studies but similar to other field assessments. In a short prospective cohort study comparing BSF to non-BSF households, odds of reported diarrheal disease in BSF households were 0.39 times the odds of reported diarrheal disease in non-BSF households. These results document high levels of sustained and effective concrete BSF use and associated improvements in water quality and health.

Migrant and seasonal farmworkers provide much of the necessary labor to harvest and process agricultural commodities desired by consumers. Little is known about the health status (especially the parasitic burden) of farm laborers, who handpick agricultural items such as fruits and vegetables, despite being implicated as a means of foodborne pathogen transmission. The goal of this research was to develop a framework to investigate enteric parasitic infections among Hispanic farmworkers in Eastern North Carolina. Seventy-one interviews were conducted, 16 stool samples were collected, and two parasite-positive workers were found. In addition, some potentially harmful health practices (e.g., self-medication) were identified. Further research is necessary to fully understand the scope of farmworker health issues and the potential risk of disseminating foodborne pathogens to humans. The study model presented provides a geographically expandable format to allow for various types of health investigations including the prevalence of other pathogens.

A number of household water treatment and safe storage technologies, such as chlorine disinfection, solar disinfection, and ceramic filtration, have been documented for their ability to reduce diarrheal disease and improve microbial water quality. The biosand filter (BSF) is a promising household water treatment technology in use by > 500,000 people globally. The purpose of this research was to document the ability of BSFs to improve water quality and to reduce diarrheal disease in user compared with non-user households in a randomized controlled trial in Bonao, Dominican Republic, during 2005-2006. During the 6-month intervention period, 75 BSF households had significantly improved drinking water quality on average compared with 79 control households (P < 0.001). Based on random intercepts logistic regression, BSF households had 0.53 times the odds of diarrheal disease as control households, indicating a significant protective effect of the BSF against waterborne diarrheal disease.

The lack of safe water creates a tremendous burden of diarrheal disease and other debilitating, life-threatening illnesses for people in the developing world. Point-of-use (POU) water treatment technology has emerged as an approach that empowers people and communities without access to safe water to improve water quality by treating it in the home. Several POU technologies are available, but, except for boiling, none have achieved sustained, large-scale use. Sustained use is essential if household water treatment technology (HWT) is to provide continued protection, but it is difficult to achieve. The most effective, widely promoted and used POU HWTs are critically examined according to specified criteria for performance and sustainability. Ceramic and biosand household water filters are identified as most effective according to the evaluation criteria applied and as having the greatest potential to become widely used and sustainable for improving household water quality to reduce waterborne disease and death.

Point-of-use (POU) drinking water treatment technology enables those without access to safe water sources to improve the quality of their water by treating it in the home. One of the most promising emerging POU technologies is the biosand filter (BSF), a household-scale, intermittently operated slow sand filter. Over 500,000 people in developing countries currently use the filters to treat their drinking water. However, despite this successful implementation, there has been almost no systematic, process engineering research to substantiate the effectiveness of the BSF or to optimize its design and operation. The major objectives of this research were to: (1) gain an understanding of the hydraulic flow condition within the filter (2) characterize the ability of the BSF to reduce the concentration of enteric bacteria and viruses in water and (3) gain insight into the key parameters of filter operation and their effects on filter performance. Three 6-8 week microbial challenge experiments are reported herein in which local surface water was seeded with E. coli, echovirus type 12 and bacteriophages (MS2 and PRD-1) and charged to the filter daily. Tracer tests indicate that the BSF operated at hydraulic conditions closely resembling plug flow. The performance of the filter in reducing microbial concentrations was highly dependent upon (1) filter ripening over weeks of operation and (2) the daily volume charged to the filter. BSF performance was best when less than one pore volume (18.3-L in the filter design studied) was charged to the filter per day and this has important implications for filter design and operation. Enhanced filter performance due to ripening was generally observed after roughly 30 days. Reductions of E. coli B ranged from 0.3 log10 (50%) to 4 log10, with geometric mean reductions after at least 30 days of operation of 1.9 log10. Echovirus 12 reductions were comparable to those for E. coli B with a range of 1 log10 to >3 log10 and mean reductions after 30 days of 2.1 log10. Bacteriophage reductions were much lower, ranging from zero to 1.3 log10 (95%) with mean reductions of only 0.5 log10 (70%). These data indicate that virus reduction by BSF may differ substantially depending upon the specific viral agent.

More than a billion people in the developing world lack access to safe and reliable sources of drinking water. Point of use (POU) household water treatment technology allows people to improve the quality of their water by treating it in the home. One emerging POU technology is the biosand filter (BSF), a household-scale, intermittently operated slow sand filter. Laboratory and field studies examined Escherichia coli reductions achieved by the BSF. During two laboratory studies, mean E. coli reductions were 94% and they improved over the period of filter use, reaching a maximum of 99%. Field analysis conducted on 55 household filters near Bonao, Dominican Republic averaged E. coli reductions of 93%. E. coli reductions by the BSF in laboratory and field studies were less than those typically observed for traditional slow sand filters (SSFs), although as for SSFs microbial reductions improved over the period of filter use. Further study is needed to determine the factors contributing to microbial reductions in BSFs and why reductions are lower than those of conventional SSFs.