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The study discussed here evaluated the presence of self-reported respiratory symptoms and their association with indoor bioaerosol concentrations over a year-long study in the El Paso, Texas, region. The authors collected air samples from homes to assess seasonal differences in bacterial and fungal bioaerosol concentrations. They distributed a health questionnaire to the participating homeowner during each seasonal air sampling. The authors used this questionnaire to assess whether the homeowners were suffering from specific symptoms prior to each sampling. Descriptive statistics and logistic regressions were conducted to model the relationship among 'high' reporters of symptoms, bioaerosols, and environmental factors. The authors collected evidence to support an association between indoor respirable bacterial concentrations and homeowners that reported at least eight respiratory symptoms (odds ratio [OR] = 1.10, p = .045). Smoking status, indoor humidity, and season also displayed associations with homeowners that reported at least eight respiratory symptoms (current smokers OR = 3.3, p = .042; indoor humidity OR = 1.5, p = .030; spring season OR = 7.2, p = .001; fall season OR = 3.4, p = .008). [ABSTRACT FROM AUTHOR]

Objectives: Rapid evolution of SARS-CoV-2 has resulted in the emergence of numerous variants, posing significant challenges to public health surveillance. Clinical genome sequencing, while valuable, has limitations in capturing the full epidemiological dynamics of circulating variants in the general population. This study aimed to monitor the SARS-CoV-2 variant community dynamics and evolution using receptor-binding domain (RBD) amplicon sequencing of wastewater samples., Methods: We sequenced wastewater from El Paso, Texas, over 17 months, compared the sequencing data with clinical genome data, and performed biodiversity analysis to reveal SARS-CoV-2 variant dynamics and evolution., Results: We identified 91 variants and observed waves of dominant variants transitioning from BA.2 to BA.2.12.1, BA.4&5, BQ.1, and XBB.1.5. Comparison with clinical genome sequencing data revealed earlier detection of variants and identification of unreported outbreaks. Our results also showed strong consistency with clinical data for dominant variants at the local, state, and national levels. Alpha diversity analyses revealed significant seasonal variations, with the highest diversity observed in winter. By segmenting the outbreak into lag, growth, stationary, and decline phases, we found higher variant diversity during the lag phase, likely due to lower inter-variant competition preceding outbreak growth., Conclusions: Our findings underscore the importance of low transmission periods in facilitating rapid mutation and variant evolution. Our approach, integrating RBD amplicon sequencing with wastewater surveillance, demonstrates effectiveness in tracking viral evolution and understanding variant emergence, thus enhancing public health preparedness., 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 © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Our objective was to deliver actionable, worksite-specific COVID-19 risk assessments and mitigation strategies tailored to vulnerable workers in one of the highest-risk areas in the US., Methods: Four trained, bilingual (English/Spanish) Community Health Workers (CHWs) recruited small businesses (i.e., ≤20 employees) across various industries and executed novel on-site infectious disease risk assessment surveys of at least one employer and one employee., Results: Of 102 participating businesses (95% Hispanic-owned), 96% were characterized as "high risk" or "very high risk" for disease transmission. All businesses reported implementing at least one practice to reduce disease transmission; however, almost half of businesses lacked at least 13 of the 17 controls identified to mitigate risk., Conclusions: Tailored, culturally sensitive outreach led by CHWs identified and educated businesses on critical hazards, and these methods may be transferable to similar communities., Competing Interests: Disclosures of Conflicts of Interest: The authors declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American College of Occupational and Environmental Medicine.)

Background: Numerous risk factors have been identified as significantly influencing outdoor workers' risk for heat stress and heat-related conditions, impacting their health, well-being, and productivity. However, the specific effects of these factors on construction workers' safety, health, and well-being remain under-researched. With climate change increasing temperatures, assessing heat stress among construction workers is imperative., Objective: To identify the barriers and facilitators influencing the safety of natural gas construction workers and evaluate an implemented heat stress intervention., Methods: In the summer of 2023, two semi-structured interviews and six focus groups were conducted with twenty-one stakeholders at a Texas natural gas construction site., Results: Key facilitators include employee preparedness, use of employer-provided resources, hydration logs, and real-time communication tools. Contrarily, the barriers include daily work schedules, access to dehydrating beverages, and generational differences with the non-implementation of mandatory rest breaks. The heat stress program was perceived as effective, surpassing recommended guidelines., Conclusion: To advance construction workers' safety, health, and well-being, both employee involvement and employer management are needed, along with no-cost accessible resources. Additionally, implementing a required routine rest break and comprehensive heat stress education, particularly for older workers, will significantly promote safety and safe work practices in hot environments. Note: in this study, the terms 'worker' and 'employee' are used interchangeably.

Rapid evolution of SARS-CoV-2 has resulted in the emergence of numerous variants, posing significant challenges to public health surveillance. Clinical genome sequencing, while valuable, has limitations in capturing the full epidemiological dynamics of circulating variants in the general population. This study utilized receptor-binding domain (RBD) amplicon sequencing of wastewater samples to monitor the SARS-CoV-2 community dynamics and evolution in El Paso, TX. Over 17 months, we identified 91 variants and observed waves of dominant variants transitioning from BA.2 to BA.2.12.1, BA.4&5, BQ.1, and XBB.1.5. Our findings demonstrated early detection of variants and identification of unreported outbreaks, while showing strong consistency with clinical genome sequencing data at the local, state, and national levels. Alpha diversity analyses revealed significant periodical variations, with the highest diversity observed in winter and the outbreak lag phases, likely due to lower competition among variants before the outbreak growth phase. The data underscores the importance of low transmission periods for rapid mutation and variant evolution. This study highlights the effectiveness of integrating RBD amplicon sequencing with wastewater surveillance in tracking viral evolution, understanding variant emergence, and enhancing public health preparedness., Competing Interests: Declaration of Competing Interest The authors declare no competing interest.

Eye infections from bacterial contamination of bulk-refillable liquid soap dispensers and artificial tear eye drops continue to occur, resulting in adverse health outcomes that include impaired vision or eye enucleation. Pseudomonas aeruginosa ( P. aeruginosa ), a common cause of eye infections, can grow in eye drop containers and refillable soap dispensers to high numbers. To assess the risk of eye infection, a quantitative microbial risk assessment for P. aeruginosa was conducted to predict the probability of an eye infection for two potential exposure scenarios: (i) individuals using bacteria-contaminated eye drops and (ii) contact lens wearers washing their hands with bacteria-contaminated liquid soap prior to placing the lens. The median risk of an eye infection using contaminated eye drops and hand soap for both single and multiple exposure events (per day) ranged from 10 -1 to 10 -4 , with contaminated eye drops having the greater risk. The concentration of P. aeruginosa was identified as the parameter contributing the greatest variance on eye infection risk; therefore, the prevalence and level of bacterial contamination of the product would have the greatest influence on health risk. Using eye drops in a single-use container or with preservatives can mitigate bacterial growth, and using non-refillable soap dispensers is recommended to reduce contamination of hand soap. Given the opportunistic nature of P. aeruginosa and its ability to thrive in unique environments, additional safeguards to mitigate bacterial growth and exposure are warranted.IMPORTANCE Pseudomonas aeruginosa ( P. aeruginosa ) is a pathogen that can persist in a variety of unusual environments and continues to pose a significant risk for public health. This quantitative microbial risk assessment (QMRA) estimates the potential human health risks, specifically for eye infections, associated with exposure to P. aeruginosa in bacteria-contaminated artificial tear eye drops and hand soap. This study applies the risk assessment framework of QMRA to evaluate eye infection risks through both consumer products. The study examines the prevalence of this pathogen in eye drops and soap, as well as the critical need to implement measures that will mitigate bacterial exposure (e.g., single-use soap dispensers and eye drops with preservatives). Additionally, limitations and challenges are discussed, including the need to incorporate data regarding consumer practices, which may improve exposure assessments and health risk estimates., Competing Interests: The authors declare no conflict of interest.

The border city of El Paso, Texas, and its water utility, El Paso Water, initiated a SARS-CoV-2 wastewater monitoring program to assess virus trends and the appropriateness of a wastewater monitoring program for the community. Nearly weekly sample collection at four wastewater treatment facilities (WWTFs), serving distinct regions of the city, was analyzed for SARS-CoV-2 genes using the CDC 2019-Novel coronavirus Real-Time RT-PCR diagnostic panel. Virus concentrations ranged from 86.7 to 268,000 gc/L, varying across time and at each WWTF. The lag time between virus concentrations in wastewater and reported COVID-19 case rates (per 100,00 population) ranged from 4-24 days for the four WWTFs, with the strongest trend occurring from November 2021 - June 2022. This study is an assessment of the utility of a geographically refined SARS-CoV-2 wastewater monitoring program to supplement public health efforts that will manage the virus as it becomes endemic in El Paso.

Background: Tracking infectious diseases at the community level is challenging due to asymptomatic infections and the logistical complexities of mass surveillance. Wastewater surveillance has emerged as a valuable tool for monitoring infectious disease agents including SARS-CoV-2 and Mpox virus. However, detecting the Mpox virus in wastewater is particularly challenging due to its relatively low prevalence in the community. In this study, we aim to characterize three molecular assays for detecting and tracking the Mpox virus in wastewater from El Paso, Texas, during February and March 2023., Methods: In this study, a combined approach utilizing three real-time PCR assays targeting the C22L, F3L, and F8L genes and sequencing was employed to detect and track the Mpox virus in wastewater samples. The samples were collected from four sewersheds in the City of El Paso, Texas, during February and March 2023. Wastewater data was compared with reported clinical case data in the city., Findings: Mpox virus DNA was detected in wastewater from all the four sewersheds, whereas only one Mpox case was reported during the sampling period. Positive signals were still observed in multiple sewersheds after the Mpox case was identified. Higher viral concentrations were found in the pellet than in the supernatant of wastewater. Notably, an increasing trend in viral concentration was observed approximately 1-2 weeks before the reporting of the Mpox case. Further sequencing and epidemiological analysis provided supporting evidence for unreported Mpox infections in the city., Interpretation: Our analysis suggests that the Mpox cases in the community is underestimated. The findings emphasize the value of wastewater surveillance as a public health tool for monitoring infectious diseases even in low-prevalence areas, and the need for heightened vigilance to mitigate the spread of Mpox disease for safeguarding global health., Funding: Center of Infectious Diseases at UTHealth, the University of Texas System, and the Texas Epidemic Public Health Institute. The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of these funding organizations., Competing Interests: The authors declare no competing interest., (© 2023 The Author(s).)

Wastewater is a discarded human by-product, but its analysis may help us understand the health of populations. Epidemiologists first analyzed wastewater to track outbreaks of poliovirus decades ago, but so-called wastewater-based epidemiology was reinvigorated to monitor SARS-CoV-2 levels while bypassing the difficulties and pit falls of individual testing. Current approaches overlook the activity of most human viruses and preclude a deeper understanding of human virome community dynamics. Here, we conduct a comprehensive sequencing-based analysis of 363 longitudinal wastewater samples from ten distinct sites in two major cities. Critical to detection is the use of a viral probe capture set targeting thousands of viral species or variants. Over 450 distinct pathogenic viruses from 28 viral families are observed, most of which have never been detected in such samples. Sequencing reads of established pathogens and emerging viruses correlate to clinical data sets of SARS-CoV-2, influenza virus, and monkeypox viruses, outlining the public health utility of this approach. Viral communities are tightly organized by space and time. Finally, the most abundant human viruses yield sequence variant information consistent with regional spread and evolution. We reveal the viral landscape of human wastewater and its potential to improve our understanding of outbreaks, transmission, and its effects on overall population health., (© 2023. The Author(s).)

Quantitative microbial risk assessment (QMRA) can be used to evaluate health risks associated with recreational beach use. This study developed a site-specific risk assessment using a novel approach that combined quantitative PCR-based measurement of microbial source tracking (MST) genetic markers (human, dog, and gull fecal bacteria) with a QMRA analysis of potential pathogen risk. Water samples ( n  = 24) from two recreational beaches were collected and analyzed for MST markers as part of a broader Beach Exposure And Child Health Study that examined child behavior interactions with the beach environment. We report here the measurements of fecal bacteria MST markers in the environmental DNA extracts of those samples and a QMRA analysis of potential health risks utilizing the results from the MST measurements in the water samples. Human-specific Bacteroides was enumerated by the HF183 Taqman qPCR assay, gull-specific Catellicoccus was enumerated by the Gull2 qPCR assay, and dog-specific Bacteroides was enumerated by the DogBact qPCR assay. Derived reference pathogen doses, calculated from the MST marker concentrations detected in recreational waters, were used to estimate the risk of gastrointestinal illness for both children and adults. Dose-response equations were used to estimate the probability of the risk of infection (P inf ) per a swimming exposure event. Based on the QMRA simulations presented in this study, the GI risk from swimming or playing in water containing a mixture of human and non-human fecal sources appear to be primarily driven by the human fecal source. However, the estimated median GI health risk for both beaches never exceeded the U.S. EPA risk threshold of 32 illnesses per 1,000 recreation events. Our research suggests that utilizing QMRA together with MST can further extend our understanding of potential recreational bather risk by identifying the source contributing the greatest risk in a particular location, therefore informing beach management responses and decision-making., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Gitter, Gidley, Mena, Ferguson, Sinigalliano, Bonacolta and Solo-Gabriele.)

Aquifer storage and recovery (ASR) can augment water supplies and hydrologic flows under varying climatic conditions. However, imposing drinking water regulations on ASR practices, including pre-treatment before injection into the aquifer, remains arguable. Microbial inactivation data- Escherichia coli , Pseudomonas aeruginosa , poliovirus type 1 and Cryptosporidium parvum -were used in a human health risk assessment to identify how the storage time of recharged water in the Floridan Aquifer enhances pathogen inactivation, thereby mitigating the human health risks associated with ingestion. We used a quantitative microbial risk assessment to evaluate the risks for a gastrointestinal infection (GI) and the associated disability-adjusted life years (DALYs) per person per year. The risk of developing a GI infection for drinking water no longer exceeded the suggested annual risk threshold (1 × 10 -4 ) by days 31, 1, 52 and 80 for each pathogen, respectively. DALYs per person per year no longer exceeded the World Health Organization threshold (1 × 10 -6 ) by days 27, <1, 43 and 72. In summary, storage time in the aquifer yields a significant reduction in health risk. The findings emphasize that considering microbial inactivation, caused by storage time and geochemical conditions within ASR storage zones, is critical for recharge water treatment processes.

Wastewater surveillance has proved to be a valuable tool to track the COVID-19 pandemic. However, most studies using wastewater surveillance data revolve around establishing correlations and lead time relative to reported case data. In this perspective, we advocate for the integration of wastewater surveillance data with dynamic within-host and between-host models to better understand, monitor, and predict viral disease outbreaks. Dynamic models overcome emblematic difficulties of using wastewater surveillance data such as establishing the temporal viral shedding profile. Complementarily, wastewater surveillance data bypasses the issues of time lag and underreporting in clinical case report data, thus enhancing the utility and applicability of dynamic models. The integration of wastewater surveillance data with dynamic models can enhance real-time tracking and prevalence estimation, forecast viral transmission and intervention effectiveness, and most importantly, provide a mechanistic understanding of infectious disease dynamics and the driving factors. Dynamic modeling of wastewater surveillance data will advance the development of a predictive and responsive monitoring system to improve pandemic preparedness and population health., Competing Interests: Declaration of Competing Interest The authors declare they have no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Molecular analysis of public wastewater has great potential as a harbinger for community health and health threats. Long-used to monitor the presence of enteric viruses, in particular polio, recent successes of wastewater as a reliable lead indicator for trends in SARS-CoV-2 levels and hospital admissions has generated optimism and emerging evidence that similar science can be applied to other pathogens of pandemic potential (PPPs), especially respiratory viruses and their variants of concern (VOC). However, there are substantial challenges associated with implementation of this ideal, namely that multiple and distinct fields of inquiry must be bridged and coordinated. These include engineering, molecular sciences, temporal-geospatial analytics, epidemiology and medical, and governmental and public health messaging, all of which present their own caveats. Here, we outline a framework for an integrated, state-wide, end-to-end human pathogen monitoring program using wastewater to track viral PPPs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Clark, Terwilliger, Avadhanula, Tisza, Cormier, Javornik-Cregeen, Ross, Hoffman, Troisi, Hanson, Petrosino, Balliew, Piedra, Rios, Deegan, Bauer, Wu, Mena, Boerwinkle and Maresso.)

Wastewater-based surveillance (WBS) has been widely used as a public health tool to monitor SARS-CoV-2 transmission. However, epidemiological inference from WBS data remains understudied and limits its application. In this study, we have established a quantitative framework to estimate COVID-19 prevalence and predict SARS-CoV-2 transmission through integrating WBS data into an SEIR-V model. We conceptually divide the individual-level viral shedding course into exposed, infectious, and recovery phases as an analogy to the compartments in a population-level SEIR model. We demonstrated that the effect of temperature on viral losses in the sewer can be straightforwardly incorporated in our framework. Using WBS data from the second wave of the pandemic (Oct 02, 2020-Jan 25, 2021) in the Greater Boston area, we showed that the SEIR-V model successfully recapitulates the temporal dynamics of viral load in wastewater and predicts the true number of cases peaked earlier and higher than the number of reported cases by 6-16 days and 8.3-10.2 folds (R = 0.93). This work showcases a simple yet effective method to bridge WBS and quantitative epidemiological modeling to estimate the prevalence and transmission of SARS-CoV-2 in the sewershed, which could facilitate the application of wastewater surveillance of infectious diseases for epidemiological inference and inform public health actions., 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 © 2022 Elsevier B.V. All rights reserved.)

Rapid and accurate diagnosis of infections is fundamental to containment of disease. Several monkeypox virus (MPV) real-time diagnostic assays have been recommended by the CDC; however, the specificity of the primers and probes in these assays for the ongoing MPV outbreak has not been investigated. We analyzed the primer and probe sequences present in the CDC recommended MPV generic real-time PCR assay by aligning those sequences against 1730 MPV complete genomes reported in 2022 worldwide. Sequence mismatches were found in 99.08% and 97.46% of genomes for the MPV generic forward and reverse primers, respectively. Mismatch-corrected primers were synthetized and compared to the generic assay for MPV detection. Results showed that the two primer-template mismatches resulted in a ~11-fold underestimation of initial template DNA in the reaction and 4-fold increase in the 95% LOD. We further evaluated the specificity of seven other real-time PCR assays used for MPV and orthopoxvirus (OPV) detection and identified two assays with the highest matching score (>99.6%) to the global MPV genome database in 2022. Genetic variations in the primer-probe regions across MPV genomes could indicate the temporal and spatial emergence pattern of monkeypox disease. Our results show that the current MPV real-time generic assay may not be optimal to accurately detect MPV, and the mismatch-corrected assay with full complementarity between primers and current MPV genomes could provide a more sensitive and accurate detection of MPV., (© 2022 Wiley Periodicals LLC.)

During time-periods oil slicks are in the marine environment (age-at-sea), weathering causes significant changes in composition and mass loss (depletion) of oil spill chemicals including the more toxic polycyclic aromatic hydrocarbons (PAHs). The goal of this study was to estimate the age-at-sea of weathered oil slicks using the oil spill module of the Connectivity Modeling System and to use this age to interpret PAH concentration measurements. Percent depletion (PD) for each measurement was computed as the percentage difference between the original and measured PAH concentration in the crude oil and weathered oil slicks, normalized upon the mass losses relative to hopane. Mean PD increased with estimated age-at-sea for all PAHs. Less PD was observed for alkylated than for parent PAHs, likely due to decreasing vapor pressure with increasing degree of alkylation. We conclude that estimated age-at-sea can be used to explain PAH depletion in weathered oil slicks. We propose PAH vapor pressure can be coupled with the model to expand capacity for predicting concentration distributions of individual parent and alkylated PAHs in weathered oil along the coastline. This new module will advance the science supporting oil spill response by providing more certain estimates of health risks from oil spills., 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 © 2022 Elsevier B.V. All rights reserved.)

The 2010 DWH disaster generated atmospheric pollutants of health concern which reached the Gulf Coast. This study evaluated whether changes in coastal air quality due to the disaster were captured by aerosol optical depth (AOD) estimated using satellite data and by ground-based monitoring of air pollution, including fine particulate matter ≤2.5 μm in aerodynamic diameter (PM 2.5 ), benzene and naphthalene. Mean monthly AOD levels were higher in May 2010 [during oil spill time], (mean AOD = 0.355), than for the prior (mean AOD = 0.258) and following years (mean AOD = 0.252) (p < 0.05). PM 2.5 concentrations and AOD were significantly correlated (R 2  = 0.59, p < 0.05), for one study area. Elevated PM 2.5 , benzene, and naphthalene concentrations coincided with downwind directions from the location of the oil slicks. A fully-coupled oil fate and transport atmospheric transport model of oil spill emissions, integrated with AOD and more extensive ground-based measurements, is recommended to predict coastal population exposures during oil spills., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Aims: Contaminated laundry can spread infections. However, current directives for safe laundering are limited to healthcare settings and not reflective of domestic conditions. We aimed to use quantitative microbial risk assessment to evaluate household laundering practices (e.g., detergent selection, washing and drying temperatures, and sanitizer use) relative to log 10 reductions in pathogens and infection risks during the clothes sorting, washer/dryer loading, folding and storing steps., Methods and Results: Using published data, we characterized laundry infection risks for respiratory and enteric pathogens relative to a single user contact scenario and a 1.0 × 10 -6 acceptable risk threshold. For respiratory pathogens, risks following cold water wash temperatures (e.g. median 14.4℃) and standard detergents ranged from 2.2 × 10 -5 to 2.2 × 10 -7 . Use of advanced, enzymatic detergents reduced risks to 8.6 × 10 -8 and 2.2 × 10 -11 respectively. For enteric pathogens, however, hot water, advanced detergents, sanitizing agents and drying are needed to reach risk targets., Significance and Impact of the Study: Conclusions provide guidance for household laundry practices to achieve targeted risk reductions, given a single user contact scenario. A key finding was that hand hygiene implemented at critical control points in the laundering process was the most significant driver of infection prevention, additionally reducing infection risks by up to 6 log 10 ., (© 2021 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd on behalf of Society for Applied Microbiology.)

Marine oil spills and the resulting environmental contamination is common along coastal areas; however, information is lacking about the safety of impacted beaches for public use, especially for the most vulnerable population: children. One route of exposure for children at oil impacted beaches is through contact with sands. The purpose of this study was to evaluate beach sand skin adherence for children under the age of seven. Each of 122 children participated in a hand press trial conducted at one of four different U.S. beaches (two in Miami, FL, and two in Galveston, TX USA). During the hand press trials, hand conditions of the children were randomized (dry, wet, or with sunscreen), and soil adherence (mass of sand per palmar surface area of the hand) and the maximum pressure applied (force applied per area of hand) was measured and calculated. Each child was instructed to press their hands on a soil laden tray for 5 s and pressure of contact was measured using a scale. Results (n = 98) showed that the average soil adherence for both palmar hands across the four beaches ranged from 0.200 to 234 mg/cm 2 with an average of 35.7 mg/cm 2 , with boys (40.4 mg/cm 2 ) showing slightly higher means than girls (31.7 mg/cm 2 ), but these differences were not significant even after adjusting for age. Among the three conditions evaluated, the highest loading was measured for children with wet hands (mean 65.3 mg/cm 2 ), followed by dry hands (mean 24.5 mg/cm 2 ). Sunscreen hands (mean 23.2 mg/cm 2 ) had the lowest loadings. The pressure of contact ranged from 0.180 to 1.69 psi and varied by age groups and by height and weight, where pressure of contact did not have a significant influence on soil adherence. The average adhered sand grain size and average ambient sand grain size both had a statistically significant impact on hand soil adherence. Overall results from this study can be utilized in exposure and risk assessment models to evaluate the possible health impacts from contaminants found in beach sands.

Oil spills can result in changes in chemical concentrations along coastlines. In prior work, these concentration changes were used to evaluate the date sediment was impacted by oil (i.e., oil exposure date). The objective of the current study was to build upon prior work by using the oil exposure date to compute oil spill chemical (OSC) concentrations in shoreline sediments before and after exposure. The new method was applied to OSC concentration measures collected during the Deepwater Horizon oil spill with an emphasis on evaluating before and after concentrations in muddy versus sandy regions. The procedure defined a grid that overlaid coastal areas with chemical concentration measurement locations. These grids were then aggregated into clusters to allow the assignment of chemical concentration measurements to a uniform coastal type. Performance of the method was illustrated for ten chemicals individually by cluster, and collectively for all chemicals and all clusters. Results show statistically significant differences between chemical concentrations before and after the calculated oil exposure dates (p < 0.04 for each of the 10 chemicals within the identified clusters). When aggregating all chemical measures collectively across all clusters, chemical concentrations were lower before oil exposure in comparison to after (p < 0.0001). Sandy coastlines exhibited lower chemical concentrations relative to muddy coastlines (p < 0.0001). Overall, the method developed is a useful first step for establishing baseline chemical concentrations and for assessing the impacts of disasters on sediment quality within different coastline types. Results may be also useful for assessing added ecological and human health risks associated with oil spills., 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 © 2020 Elsevier Ltd. All rights reserved.)

Various methods exist to determine the surface area of hands. The consistency of these methods is essential given that risk assessments utilize hand surface area (HSA) to quantify exposure to environmental contaminants. HSA is also utilized in the clinical setting to estimate size of burns, and to determine specific treatments and medication dosages. A reliable method of surface area measurement is important to guide these decisions, especially in children who are vulnerable to environmental contaminants and medication side effects. Despite this, fewer HSA-determining studies have been performed for children compared to adults. In this study, 122 children completed hand tracings, and the tracings were digitized using an ImageJ program to determine HSA. Six previously published methods of determining HSA were utilized based on the child's height, weight, and length and width of hand. Children were analyzed by age group including 0-2, 3-4, and 5-6 years. The HSA measurements determined by five of the six methods were statistically different from HSA determined using direct hand tracings/Image J methodology (p < 0.001). The single remaining study that did not differ significantly from the hand tracing method provided a uniform hand to total body surface area (TBSA) ratio for children of all ages. Based on these results, we propose a novel age-group-specific ratio utilizing the HSA results from hand tracings and TBSA calculations. The percentages of TBSA that reflect HSA for children aged 0-2, 3-4 and 5-6 years were 0.91%, 0.90% and 0.87%, respectively. These percentages should be considered for use in risk assessments and the clinical setting to guide treatment and prognosis.

The human health impact from exposure to contaminated shorelines following an oil spill event has been investigated to some extent. However, the health risks to children have largely been characterized through the use of surveys and extrapolation from adult health outcomes. There is limited information on children's behaviors during beach play requiring assumptions made based on observations from play activities in home settings. The Beach Exposure and Child Health Study (BEACHES) quantified specific beach activities that can be used to inform human health risk assessments of children playing on beaches impacted by oil spills. The results of this study characterize children's risk of cancer from exposure to oil spill chemicals by incorporating exposure-related information collected from the BEACHES study and by assuming oral, dermal, and inhalation exposure routes. Point risk estimates are compared with a previous, similar study that applied default exposure parameter values obtained from the published literature. The point risk estimates informed by BEACHES data are one order of magnitude lower compared with the previous risk assessment, with dermal exposures the overall risk driver in both. Additional Monte Carlo simulations evaluating the BEACHES data provide ranges of health risks with the highest estimates associated with dermal and oral exposure routes.

The Beach Exposure and Child Health Study (BEACHES) quantified the behavior of children at recreational beach areas to evaluate how various behaviors might affect their exposure to environmental contaminants such as bacteria and chemicals. Due to limited information in the study about abrasions, we conducted a literature review to examine how marine bacteria cause infections in open wounds. The literature review revealed possible adverse health effects from the bacterium Vibrio vulnificus due to its increasing prevalence and the severity of infection. We used data from the BEACHES study to review children's behavior and their susceptibility to abrasions. Children six years of age and younger were evaluated before and after 1 hour of play for open or healing abrasions at two beaches in Miami-Dade County, Florida (Crandon and Haulover), and two beaches in Galveston County, Texas (Stewart and Seawall). The children were videotaped to monitor their activities and to determine the behavior that would increase their susceptibility to obtaining abrasions. Overall, 58.2% of the children had at least one existing abrasion before playing at the beach, while 8.2% of the children acquired a new abrasion during their time at the beach. Children who acquired new abrasions most often played in the sea water, with new abrasions most frequently occurring on exposed skin surfaces such as the knees. Proper wound care before and after visiting the beach should be encouraged to minimize the risk of bacterial infection, especially considering the possible detrimental impacts that can be caused by some bacterial pathogens through wound exposures., Competing Interests: The authors declare no conflict of interest.

To evaluate the association between the presence of asthma and allergy, and airborne endotoxin in homes of school-age children in Kaohsiung City, Taiwan, with a case-control study design by matching the age and class exposure. Data collection of home visits included an interviewer-administered questionnaire and air sampling of participants' homes for endotoxin, bacteria, and fungi, as well as temperature and relative humidity measurements. Endotoxin was detected in all air samples with a median value of 0.67 EU m -3 . In the adjusted logistic regression model, household airborne endotoxin was associated with higher prevalence of asthma and allergy; OR = 4.88 (95% CI 1.16-20.55) for Q3 (between 0.67 and 1.97 EU m  -3 ) vs. Q1 (< 0.31 EU m  -3 ), with statistical significance. Airborne fungi were associated with higher prevalence of asthma and allergy; OR = 4.47 (95% CI 1.13-17.69) for Q3 (between 314 and 699 CFU m  -3 ) vs. Q1 (< 159 CFU m  -3 ) in adjusted logistic regression models. Airborne endotoxin and fungi were significantly associated with children's asthma and allergy.

Oil spills can result in changes in chemical contaminant concentrations along coastlines. When concentrations are measured along the Gulf of Mexico over time, this information can be used to evaluate oil spill shoreline exposure dates. The objective of this research was to identify more accurate oil exposure dates based on oil spill chemical concentrations changes (CCC) within sediments in coastal zones after oil spills. The results could be used to help improve oil transport models and to improve estimates of oil landings within the nearshore. The CCC method was based on separating the target coastal zone into segments and then documenting the timing of large increases in concentration for specific oil spill chemicals (OSCs) within each segment. The dataset from the Deepwater Horizon (DWH) oil spill was used to illustrate the application of the method. Some differences in exposure dates were observed between the CCC method and between oil spill trajectories. Differences may have been caused by mixing at the freshwater and sea water interface, nearshore circulation features, and the possible influence of submerged oil that is unaccounted for by oil spill trajectories. Overall, this research highlights the benefit of using an integrated approach to confirm the timing of shoreline exposure., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: To date, the effect of household airborne pollutants on the association between airborne endotoxin and lung function of schoolchildren is unknown., Objectives: The objective of this study is to evaluate whether indoor air pollutants such as carbon monoxide (CO), carbon dioxide (CO 2 ), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), ozone (O 3 ), particulate matter with aerodynamic diameter <10 and 2.5 μm (PM 10 , PM 2.5 ) can modify the association between airborne endotoxin and school children's lung function in a heavy industrial city in Taiwan., Methods: We recruited 120 elementary school-age children in Kaohsiung City, Taiwan. Aerosol samples were collected on a filter membrane for 24 h period and then analyzed for endotoxin. Air pollutants were measured for 24 h in living rooms while school children's lung function was measured. The modification of air pollutants on the relationship between airborne endotoxin and children's lung function was estimated after adjusting the gender, age, height, weight, and case-control status., Results: We found that both O 3 and PM 10 concentrations significantly modified the relationships between airborne endotoxin and school children's lung function. Among children living in homes with O 3  ≥ 0.01 ppm or PM 10  ≥ 62 μg/m 3 , airborne endotoxin was negatively associated with lung functions, whereas among those living in homes with O 3  < 0.01 ppm or PM 10  < 62 μg/m 3 , airborne endotoxin was positively associated with lung functions., Conclusions: The indoor air pollutant concentration of O 3 and PM 10 modifies the association between airborne endotoxin and school children's lung function., (Copyright © 2019. Published by Elsevier B.V.)

Oil Spill Chemicals (OSCs) represent a risk to the environment and human health, especially in nearshore environments used for recreational purposes. Importantly, the starting point for human health risk assessment is to define the concentration of OSCs at nearshore locations. The objective of this study was to evaluate nearshore sampling data of OSC concentrations in different environmental matrices within time-space specific categories. The categories correspond to OSC concentration values for samples collected prior to nearshore oiling, post nearshore oiling and at no time impacted by oil as predicted by historic oil spill trajectories generated by an Oil Spill Trajectory Model. In general, concentration values for the post category were higher than prior which were higher than unimpacted. Results show differences in PAH concentration patterns within each matrix and for each category. Concentration frequency distributions for most chemicals in each category were log-normally distributed., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Anthropogenic contamination of beaches in the south of Brazil was assessed by detection of Escherichia coli, human mastadenovirus species C (HAdV-C) and F (HAdV-F) and hepatitis E virus (HEV). Sampling was carried out in October (2016), and in January, April and July (2017). Water, sediment, sea surface microlayer (SML), bivalves, and air sentinel samples were evaluated. Quantitative microbiological risk assessment (QMRA) was used to estimate the probability of swimmer infection. HAdV-C was present in 26% of the samples, for both qPCR and viral isolation. The highest rates of detection in genomic copies (GC) were in water (2.42E+10 GC/L), SML (2.08E+10 GC/L), sediment (3.82E+08 GC/g) and bivalves (3.91E+07 GC/g). QMRA estimated daily and annual risks with a maximum value (9.99E-01) in almost all of the samples. Viable HAdV-C was often detected in the SML, pointing that this is a source of infection for people bathing in these waters., (Copyright © 2018. Published by Elsevier Ltd.)

In this study, total coliforms (TC), Escherichia coli, enterovirus (EV), rotavirus (RV), and human mastadenovirus species C and F (HAdV-C and HAdV-F) were evaluated in water samples from Belo Stream. For HAdV-C and F, the infectivity was assessed by integrated cell culture quantitative real-time polymerase chain reaction (ICC-qPCR). Samples were collected monthly (May/2015 to April/2016) at four sites. Viral analyses were performed for both ultracentrifuge-concentrated and unconcentrated samples. For site P4 (used for recreational purposes), QMRA was applied to estimate health risks associated with exposure to E. coli and HAdV-C and F. TC and E. coli were present throughout the collection period. EV and RV were not detected. HAdV-C were present in 8.51% (1.89E + 06 to 2.28E + 07 GC (Genomic Copies)/L) and 21.27% (2.36E + 05 to 1.29E + 07 GC/L) for unconcentrated and concentrated samples, respectively. For HAdV-F were 12.76% (2.77E + 07 to 3.31E + 08 GC/L) and 48.93% (1.10E + 05 to 4.50E + 08 GC/L) for unconcentrated and concentrated samples, respectively. For unconcentrated samples, infectivity for HAdV-C was detected in 37.20% (1st ICC-qPCR) and 25.58% (2nd ICC-qPCR). For HAdV-F, infectivity was detected in 6.97% (1st ICC-qPCR) and 6.97% (2nd ICC-qPCR). For concentrated samples, HAdV-C infectious was observed in 17.02% (1st ICC-qPCR) and in 8.51% (2nd ICC-qPCR). For HAdV-F, were present in 8.51% for both 1st and 2nd ICC-qPCR. Statistical analyzes showed significant difference between the collection sites when analyzed the molecular data of HAdV-F, data of TC and E. coli. Correlation tests showed direct correlation between HAdV-F with E. coli and TC. E. coli concentrations translated to the lowest estimates of infection risks (8.58E-05 to 2.17E-03). HAdV-F concentrations were associated with the highest infection risks at 9.99E-01 and for group C, 1.29E-01 to 9.99E-01. These results show that commonly used bacterial indicators for water quality may not infer health risks associated with viruses in recreational freshwaters., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Jumping on the bed is a favorite behavior of children; however, no study has investigated the increased air pollutants resulting from jumping on the bed. Therefore, we aimed to investigate the elevated concentrations of particulate matter (PM) and bioaerosols from jumping on the bed and making the bed. Simulation of jumping on the bed and making the bed was performed at sixty schoolchildren's houses in Taiwan. PM 10 , PM 2.5 , PM 1 (PM with aerodynamic diameter less than 10, 2.5, and 1 μm, respectively) and airborne bacteria, fungi and endotoxin concentrations were simultaneously measured over simulation and background periods. Our results show the increase of PM 10 , PM 2.5 , PM 1 , airborne bacteria and fungi through the behavior of jumping on the bed (by 414 μg m-3, 353 μg m-3, 349 μg m-3, 6569 CFU m-3 and 978 CFU m-3, respectively). When making the bed, the PM 10 , PM 2.5 , PM 1 , airborne bacteria and fungi also significantly increased by 4.69 μg m-3, 4.09 μg m-3, 4.15 μg m-3, 8569 CFU m-3, and 779 CFU m-3, respectively. Airborne endotoxin concentrations significantly increased by 21.76 EU m-3 following jumping on the bed and making the bed. Moreover, when jumping on the bed, higher PM 2.5 and PM 1 concentrations in houses with furry pets rather than no furry pets, and less airborne fungi in apartments than in townhouses were found. For making the bed, lower airborne fungi was found in houses using essential oils rather than no essential oils using. The airborne endotoxin concentrations were positively associated with furry pets and smokers in the homes and negatively correlated to the home with window opening with a statistical significance during the periods of jumping on the bed and making the bed. In conclusion, significant increases of PM and bioaerosols during jumping on the bed and making the bed may need to be concerned., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Survival of bacterial pathogens in different environments is due, in part, to their ability to form biofilms. Four wild-type Salmonella enterica strains, two Oranienburg and two Saintpaul isolated from river water and animal feces, were tested for biofilm formation at the air-liquid interface under stressful conditions (pH and salinity treatments such as pH 3, NaCl 4.5 w/v; pH 7, NaCl 4.5 w/v; pH 10, NaCl 4.5 w/v; pH 3, Nacl 0.5 w/v; pH 7, NaCl 0.5 w/v; and pH 10, NaCl 0.5 w/v); Salmonella Typhimurium DT104 was used as a control strain. Salmonella Oranienburg and Saintpaul from feces were moderately hydrophobic and motile, while S. Saintpaul from water and the control strain S. Typhimurium showed high hydrophobicity, which helped them form more resistant biofilms than S. Oranienburg. Under stressful conditions, all strains experienced difficulties in forming biofilms. Salmonella Saintpaul and Typhimurium expressed the red dry and rough (RDAR) morphotype and were able to form biofilm at air-liquid interface, contrarily to Oranienburg that showed incomplete rough morphology. This study contributes to the knowledge of biofilm formation as a survival strategy for Salmonella in aquatic environments.

Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency's (EPA's) monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V) and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene) were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10(-6) range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children's beach play habits, which are necessary to more accurately assess exposure scenarios and health risks., Competing Interests: The authors declare no conflict of interest.

Background: It is generally agreed that contaminated hospital surfaces play a role in the transmission of hospital-acquired infections (HAIs). The ability of an antimicrobial agent, engineered at Emory University, to reduce bacterial bioburden on hospital surfaces was examined. A quantitative microbial risk assessment was also conducted to quantify the potential reduction of human health risks associated with application of this antimicrobial product., Methods: A 1-arm, prospective observational study was conducted. High-frequency contact surfaces within 18 hospital patient rooms were sampled in between patient use. Negative binomial regression with repeated measures was used to examine log CFU/100 cm(2) reductions in total, gram-negative, and Staphylococcus aureus microorganisms. Standard risk assessment methods were used., Results: Multivariate regression demonstrated significant reductions in gram-negative (P < .0001) and S aureus (P = .009) bacteria with increasing patient turnover. No reduction was observed in total bacteria (P = .93). Infection risks were reduced by 4 and 3 logs for gram-positive and gram-negative bacteria, respectively. These risk reductions, along with HAI survey studies, suggest that application of this antimicrobial product could prevent as many as 5%-10% of HAIs., Conclusions: This study was the first evaluation of a distinctive antimicrobial agent for hospital surface treatment. The findings provide support for the utility of an antimicrobial product in potentially reducing HAI transmission from contaminated environment surfaces., (Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

This study was undertaken to identify water intake and source patterns among a population that resides in a hot, arid region on the US-Mexico border. A cross-sectional community-based survey was conducted among households in the neighbouring cities of El Paso, TX, USA and Ciudad Juárez, Chihuahua, Mexico to obtain data on the quantity and source of water consumed. The study was also designed to identify factors that impact water consumption patterns, including gender, demographics, socio-economic status, cultural characteristics, health status, types of occupations and residences, available water sources and outdoor temperature, among many others. Of all factors studied, outdoor air temperature was found to have the strongest impact upon water intake quantity. Specifically, among the survey participants, when the outdoor air temperature exceeded 90 °F, water consumption increased by 28 %. Additionally, it was found that participants in this region consumed approximately 50 % more water than the values reported in previous studies.

Aims: This study aimed to determine if the children's leisure activities impact the presence of pathogens on their hands and toys., Methods & Results: To assess the microbiological hazard in playground areas, a pilot study that included 12 children was conducted. We then conducted an intervention study; children's hands and toys were washed before playing. Faecal coliforms, pathogenic bacteria and Giardia lamblia were quantified by membrane filtration, selective media and flotation techniques, respectively; rotavirus, hepatitis A and rhinovirus by RT-PCR. Pilot study results revealed faecal contamination on children's hands and toys after playing on sidewalks and in public parks. Pathogenic bacteria, hepatitis A and G. lamblia on children's hands were also found. In the intervention study, Staphylococcus aureus and Klebsiella pneumoniae were found on children's hands at concentrations up to 2·5 × 10(4) and 1 × 10(4) CFU hands(-1), respectively. E. coli and Kl. pneumoniae were detected on toys (2·4 × 10(3) and 2·7 × 10(4) CFU toy(-1), respectively). Salmonella spp, Serratia spp and G. lamblia cysts were also present on toys., Conclusion: Children's play activities influence microbial presence on hands and toys; the transfer seems to occur in both ways., Significance and Impact of the Study: Control strategy needs to be implemented to protect children from infectious diseases., (© 2014 The Society for Applied Microbiology.)

Background: Melioidosis is a severe bacterial infection caused by Burkholderia pseudomallei with a high case-fatality rate. Epidemiological and animal studies show the possibility of inhalation transmission. However, no B. pseudomallei concentrations in ambient air have been researched. Here, we developed a method to quantify ambient B. pseudomallei and then measured concentrations of ambient B. pseudomallei during the typhoon season and the non-typhoon season to determine the factors influencing ambient B. pseudomallei levels., Methods: We quantified ambient B. pseudomallei by using a filter/real-time qPCR method in the Zoynan Region in Kaohsiung, southern Taiwan. Twenty-four hour samples were collected at a sampling rate of 20 L/min every day from June 11 to December 21, 2012 including during the typhoon season (June to September) and reference season (October to December)., Results: We successfully developed a filtration/real-time qPCR method to quantify ambient B. pseudomallei. To our knowledge, this is the first report describing concentrations of ambient B. pseudomallei. Ambient B. pseudomallei were only detected during the typhoon season when compared to the reference season. For the typhoons affecting the Zoynan Region, the positive rates of ambient B. pseudomallei were very high at 80% to 100%. During June to December, rainfall was positively correlated with ambient B. pseudomallei with a statistical significance. Sediment at a nearby pond significantly influenced the concentration of ambient B. pseudomallei. During the typhoon month, the typhoon was positively correlated with ambient B. pseudomallei whereas wind speed was reversely correlated with ambient B. pseudomallei., Conclusions: Our data suggest the possibility of transmission of B. pseudomallei via inhalation during the typhoon season.

Consumption of raw oysters is an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, efficient postharvest oyster treatment technology is needed to reduce public health risks. This study evaluated the inactivation of HAV and the NoV research surrogate, murine norovirus-1 (MNV-1), in oysters (Crassostrea virginica) by electron beam (E-beam) irradiation. The reduction of potential infection risks was quantified for E-beam irradiation technology employed on raw oysters at various virus contamination levels. The E-beam dose required to reduce the MNV and HAV titer by 90% (D(10) value) in whole oysters was 4.05 (standard deviations [SD], ±0.63) and 4.83 (SD, ±0.08) kGy, respectively. Microbial risk assessment suggests that if a typical serving of 12 raw oysters was contaminated with 10(5) PFU, a 5-kGy treatment would achieve a 12% reduction (from 4.49 out of 10 persons to 3.95 out of 10 persons) in NoV infection and a 16% reduction (from 9.21 out of 10 persons to 7.76 out of 10 persons) in HAV infections. If the serving size contained only 10(2) PFU of viruses, a 5-kGy treatment would achieve a 26% reduction (2.74 out of 10 persons to 2.03 out of 10 persons) of NoV and 91% reduction (2.1 out of 10 persons to 1.93 out of 100 persons) of HAV infection risks. This study shows that although E-beam processing cannot completely eliminate the risk of viral illness, infection risks can be reduced.

Three drinking water treatment plants (DWTPs) differing in source water and treatment capacity were investigated for the potential passage of waterborne protozoan (oo)cysts through conventional processing. DWTP I (15,000 L/s), DWTP II (7,500 L/s) and DWTP III (4,300 L/s) provide drinking water for approximately 2.7 million inhabitants of the Metropolitan District of Caracas (Venezuela). The US Environmental Protection Agency Method 1623 for detection of Cryptosporidium and Giardia was used to analyze raw water and finished drinking water samples collected from the three plants. (Oo)cyst recovery efficiencies varied between 23 and 84%. The concentration of confirmed (oo)cysts detected in raw water samples ranged between 1 and 100 per 100 L. (Oo)cyst levels in finished water samples ranged from 2 to 25 per 100 L. These data indicated that the conventional treatment process to produce finished water at two filtration plants was not effective in preventing the passage of protozoan (oo)cysts. Monitoring strategies that include multiple microbial indicators and waterborne pathogens are strongly recommended for accurate source water characterization and for verification of the effectiveness of treatment process barriers to microbial breakthrough in the finished water.

Fresh produce, such as lettuce and spinach, serves as a route of food-borne illnesses. The U.S. FDA has approved the use of ionizing irradiation up to 4 kGy as a pathogen kill step for fresh-cut lettuce and spinach. The focus of this study was to determine the inactivation of poliovirus and rotavirus on lettuce and spinach when exposed to various doses of high-energy electron beam (E-beam) irradiation and to calculate the theoretical reduction in infection risks that can be achieved under different contamination scenarios and E-beam dose applications. The D(10) value (dose required to reduce virus titers by 90%) (standard error) of rotavirus on spinach and lettuce was 1.29 (± 0.64) kGy and 1.03 (± 0.05) kGy, respectively. The D(10) value (standard error) of poliovirus on spinach and lettuce was 2.35 (± 0.20) kGy and 2.32 (± 0.08) kGy, respectively. Risk assessment of data showed that if a serving (∼14 g) of lettuce was contaminated with 10 PFU/g of poliovirus, E-beam irradiation at 3 kGy will reduce the risk of infection from >2 in 10 persons to approximately 6 in 100 persons. Similarly, if a serving size (∼0.8 g) of spinach is contaminated with 10 PFU/g of rotavirus, E-beam irradiation at 3 kGy will reduce infection risks from >3 in 10 persons to approximately 5 in 100 persons. The results highlight the value of employing E-beam irradiation to reduce public health risks but also the critical importance of adhering to good agricultural practices that limit enteric virus contamination at the farm and in packing houses.

Objective: A higher incidence of infectious disease has been documented in U.S. regions bordering Mexico compared with non-border areas. We assessed the prevalence of important gastrointestinal infections in Ciudad Juarez, Mexico, and El Paso, Texas, the largest binational community along the U.S.-Mexico border., Methods: Fecal specimens from a sample of the asymptomatic population representing all ages were tested for Helicobacter pylori (H. pylori), Cryptosporidium spp., Giardia spp., and other intestinal parasitic pathogens using flotation, immunoassays, and/or polymerase chain reaction. We also measured indicators of microbiological contamination of drinking water, hands of food preparers, and kitchen surfaces., Results: Overall, of the 386 participants, H. pylori was present in 38.2%, Taenia spp. in 3.3%, Giardia spp. in 2.7%, Cryptosporidium spp. in 1.9%, Entamoeba dispar in 1.3%, and Ascaris lumbricoides and Necator americanus in 0.3% of the study subjects; Cyclospora spp. and Entamoeba histolytica were not found. H. pylori infection was associated with handwashing (prevalence ratio [PR] = 1.3, 95% confidence interval [CI] 1.0, 1.8). Taenia spp. was found more often on the U.S. side (PR=8.6, 95% CI 2.3, 30.8). We did not find an association between these infections and the occurrence of total coliforms or fecal coliforms on kitchen surfaces. In addition, Escherichia coli was not found in any drinking water sample., Conclusion: The study results indicated that H. pylori and Taenia spp. infections may be highly prevalent along the U.S.-Mexico border. Additional research is necessary to adequately characterize the prevalence, as well as determine whether interventions that reduce these infections are warranted.

The mode of transmission of Helicobacter pylori, a bacterium causing gastric cancer and peptic ulcer disease, is unknown although waterborne transmission is a likely pathway. This study investigated the hypothesis that access to treated water and a sanitary sewerage system reduces the H. pylori incidence rate, using data from 472 participants in a cohort study that followed children in Juarez, Mexico, and El Paso, Texas, from April 1998, with caretaker interviews and the urea breath test for detecting H. pylori infection at target intervals of six months from birth through 24 months of age. The unadjusted hazard ratio comparing bottled/vending machine water to a municipal water supply was 0.71 (95% confidence interval (CI): 0.50, 1.01) and comparing a municipal sewer connection to a septic tank or cesspool, 0.85 (95% CI: 0.60, 1.20). After adjustment for maternal education and country, the hazard ratios decreased slightly to 0.70 (95% confidence interval: 0.49, 1.00) and 0.77 (95% confidence interval: 0.50, 1.21), respectively. These results provide moderate support for potential waterborne transmission of H. pylori.

A rise in foodborne outbreaks in the United States associated with fresh produce has resulted in increased concerns with the importation of fruits and vegetables. Mexico is a major exporter of produce to the United States, particularly tomatoes and bell peppers. A quantitative microbial risk assessment (QMRA) was conducted to evaluate the public health impact of protozoan-laden water irrigating produce in Culiacan, Sinaloa, Mexico. Specifically, a QMRA was conducted to address the human health impact associated with consumption of tomatoes, bell peppers, cucumbers, and lettuce irrigated with water contaminated with Cryptosporidium and Giardia. Yearly infection risks were estimated and assumed a 120-day exposure in a given year. Annual risks range from 9 x 10(-6) for Cryptosporidium at the lowest concentration associated with bell peppers to almost 2 x 10(-1) for exposure to Giardia on lettuce at the highest detected concentration. With the relatively high number of illnesses resulting from produce-related outbreaks, addressing pre- and postharvest points of contamination for fruits and vegetables consumed raw should be a food industry priority. This research shows how QMRA can be used to interpret microbial contamination data for public health significance and subsequently provide the foundation for guideline development.

Piped water is available in Ciudad Juarez, Chihuahua, Mexico, but residual disinfectant is not reliably found in the public drinking water supply. Lack of confidence in the public supply leads many residents to rely on bottled water. To provide consistent disinfection, two health clinics were equipped with ultraviolet disinfection systems, and neighboring households were encouraged to obtain their drinking water from the treatment systems. Use of the treated water declined from 62% of self-selected study participants at the time of the first visit to 40% at the second visit. During the first visit, diarrhea prevalence was similar among households using treated water and other water sources yet diarrhea prevalence was higher among households using the treated water during the second visit. Microbiological quality of the treated water in the homes was not demonstrably superior to that of other sources.

Adenoviruses are associated with numerous disease outbreaks, particularly those involving d-cares, schools, children's camps, hospitals and other health care centers, and military settings. In addition, adenoviruses have been responsible for many recreational water outbreaks, including a great number of swimming pool outbreaks than any other waterborne virus (Gerba and Enriquez 1997). Two drinking water outbreaks have been documented for adenovirus (Divizia et al. 2004; Kukkula et al. 1997) but none for food. Of the 51 known adenovirus serotypes, one third are associated with human disease, while other infections are asymptomatic. Human disease associated with adenovirus infections include gastroenteritis, respiratory infections, eye infections, acute hemorrhagic cystitis, and meningoencephalitis (Table 2). Children and the immunocompromised are more severely impacted by adenovirus infections. Subsequently, adenovirus is included in the EPA's Drinking Water Contaminant Candidate List (CCL), which is a list of unregulated contaminants found in public water systems that may pose a risk to public health (National Research Council 1999). Adenoviruses have been detected in various waters worldwide including wastewater, river water, oceans, and swimming pools (Hurst et al. 1988; Irving and Smith 1981; Pina et al. 1998). Adenoviruses typically outnumber the enteroviruses, when both are detected in surface waters. Chapron et al. (2000) found that 38% of 29 surface water samples were positive for infectious Ad40 and Ad41. Data are lacking regarding the occurrence of adenovirus in water in the US, particularly for groundwater and drinking water. Studies have shown, however, that adenoviruses survive longer in water than enteroviruses and hepatitis A virus (Enriquez et al. 1995), which may be due to their double-stranded DNA. Risk assessments have been conducted on waterborne adenovirus (Crabtree et al. 1997; van Heerden et al. 2005c). Using dose-response data for inhalation from Couch et al. (1966), human health risks of infection, illness and death have been determined for various adenovirus exposures. Crabtree et al. (1997) conclude that, even at an adenovirus concentration of 1 per 1,000 L of drinking water, annual risks of infection exceed the suggested risk recommendation of 1 x 10(-4) per yr (Regli et al. 1991) (Table 8). Using the same exposure and dose-response assumptions, van Heerden et al. (2005c) determined annual risks of infection to be 1-1.7 x 10(-1) for two drinking water samples from South Africa containing 1.40 and 2.45 adenoviruses per 10,000 L, respectively. This present study estimated annual risks of infection associated with varying levels of adenoviruses per 100 L (Table 9). By assuming a 2 L/d exposure and utilizing the exponential model at r = 0.4172 (Haas et al. 1993), yearly risks exceed the risk recommendation of 1 x 10(-4) at every exposure level. There are limited data regarding the removal of adenoviruses by conventional water treatment or other physical-chemical treatment processes, but studies do suggest that adenoviruses are of equal or greater sensitivity to oxidizing disinfectants, when compared to waterborne viruses (the most resistant to ultraviolet light). Data suggest that the chlorine doses applied to control other waterborne viruses are more effective against adenovirus, resulting in a greater than 4-log10 removal of adenoviruses by conventional treatment and chlorination. If treatment can achieve a 4-log10 removal of adenoviruses, then, based on the risk levels presented in Table 9, surface water concentrations should not exceed 0.5 adenoviruses per 100 L (Fig. 2). More data are needed regarding effectiveness of water treatment against adenovirus and the human-virus dose-response relationship to fully understand the role of adenovirus as a waterborne public health threat.

P. aeruginosa is part of a large group of free-living bacteria that are ubiquitous in the environment. This organism is often found in natural waters such as lakes and rivers in concentrations of 10/100 mL to >1,000/100 mL. However, it is not often found in drinking water. Usually it is found in 2% of samples, or less, and at concentrations up to 2,300 mL(-1) (Allen and Geldreich 1975) or more often at 3-4 CFU/mL. Its occurrence in drinking water is probably related more to its ability to colonize biofilms in plumbing fixtures (i.e., faucets, showerheads, etc.) than its presence in the distribution system or treated drinking water. P. aeruginosa can survive in deionized or distilled water (van der Jooij et al. 1982; Warburton et al. 1994). Hence, it may be found in low nutrient or oligotrophic environments, as well as in high nutrient environments such as in sewage and in the human body. P. aeruginosa can cause a wide range of infections, and is a leading cause of illness in immunocompromised individuals. In particular, it can be a serious pathogen in hospitals (Dembry et al. 1998). It can cause endocarditis, osteomyelitis, pneumonia, urinary tract infections, gastrointestinal infections, and meningitis, and is a leading cause of septicemia. P. aeruginosa is also a major cause of folliculitis and ear infections acquired by exposure to recreational waters containing the bacterium. In addition, it has been recognized as a serious cause of keratitis, especially in patients wearing contact lenses. P. aeruginosa is also a major pathogen in burn and cystic fibrosis (CF) patients and causes a high mortality rate in both populations (MOlina et al. 1991; Pollack 1995). P. aeruginosa is frequently found in whirlpools and hot tubs, sometimes in 94-100% of those tested at concenrations of <1 to 2,400 CFU/mL. The high concentrations found probably result from the relatively high temperatures of whirlpools, which favor the growth of P. aeruginosa, and the aeration which also enhances its growth. The organism is usually found in whirlpools when the chlorine concentrations are low, but it has been isolated even in the presence of 3.00 ppm residual free chlorine (Price and Ahearn 1988). Many outbreaks of folliculitis and ear infections have been reportedly associated with the use of whirlpools and hot tubs that contain P. aeruginosa (Ratnam et al. 1986). Outbreaks have also been reported from exposure to P. aeruginosa in swimming pools and water slides. Although P. aeruginosa has a reputation for being resistant to disinfection, most studies show that it does not exhibit any marked resistance to the disinfectants used to treat drinking water such as chlorine, chloramines, ozone, or iodine. One author, however, did find it to be slightly more resistant to UV disinfection than most other bacteria (Wolfe 1990). Although much has been written about biofilms in the drinking water industry, very little has been reported regarding the role of P. aeruginosa in biofilms. Tap water appears to be a significant route of transmission in hospitals, from colonization of plumbing fixtures. It is still not clear if the colonization results from the water in the distribution system, or personnel use within the hospital. Infections and colonization can be significantly reduced by placement of filters on the water taps. The oral dose of P. aeruginosa required to establish colonization in a healthy subject is high (George et al. 1989a). During dose-response studies, even when subjects (mice or humans) were colonized via ingestion, there was no evidence of disease. P. aeruginosa administered by the aerosol route at levels of 10(7) cells did cause disease symptoms in mice, and was lethal in aerosolized doses of 10(9) cells. Aerosol dose-response studies have not been undertaken with human subjects. Human health risks associated with exposure to P. aeruginosa via drinking water ingestion were estimated using a four-step risk assessment approach. The risk of colonization from ingesting P. aeruginosa in drinking water is low. The risk is slightly higher if the subject is taking an antibiotic resisted by P. aeruginosa. The fact that individuals on ampicillin are more susceptible to Pseudomonas gastrointestinal infection probably results from suppression of normal intestinal flora, which would allow Pseudomonas to colonize. The process of estimating risk was significantly constrained because of the absence of specific (quantitative) occurrence data for Pseudomonas. Sensitivity analysis shows that the greatest source of variability/uncertainty in the risk assessment is from the density distribution in the exposure rather than the dose-response or water consumption distributions. In summary, two routes appear to carry the greatest health risks from contacting water contaminated with P. aeruginosa (1) skin exposure in hot tubs and (2) lung exposure from inhaling aerosols.

A key objective of the Good Agricultural Practices (GAP) program is to reduce the potential for produce to become contaminated with microbial pathogens, such as through irrigation water. Without microbial standards, however, it is impractical to decide whether there is a need to disinfect, a need to institute watershed protection programs, or a need to institute post-harvest disinfection regimes. To develop such standards, quantitative microbial risk assessments can be performed using pathogen monitoring data for produce. This paper presents an approach which can be used towards the application of a risk assessment framework to developing microbial standards for fresh produce. Risks of infection are estimated using typical monitoring data of Salmonella detected on carrots and assuming various scenarios of the likelihood of an individual consuming a contaminated serving of carrots in a given year. Estimated annual risks of infection range from 2.20 x 10(-5) to 2.16 x 10(-3), assuming 1% and 100% of an individual's carrot servings are contaminated, respectively. In addition, critical factors are identified which need to be incorporated in such a risk assessment approach as well as their impact on risk estimates to provide growers with benchmarks which may be targeted to reduce health risks.