HMGB1-mediated restriction of EPO signaling contributes to anemia of inflammation.

Anemia of inflammation, also known as anemia of chronic disease, is refractory to erythropoietin (EPO) treatment, but the mechanisms underlying the EPO refractory state are unclear. Here, we demonstrate that high mobility group box-1 protein (HMGB1), a damage-associated molecular pattern molecule recently implicated in anemia development during sepsis, leads to reduced expansion and increased death of EPO-sensitive erythroid precursors in human models of erythropoiesis. HMGB1 significantly attenuates EPO-mediated phosphorylation of the Janus kinase 2/STAT5 and mTOR signaling pathways. Genetic ablation of receptor for advanced glycation end products, the only known HMGB1 receptor expressed by erythroid precursors, does not rescue the deleterious effects of HMGB1 on EPO signaling, either in human or murine precursors. Furthermore, surface plasmon resonance studies highlight the ability of HMGB1 to interfere with the binding between EPO and the EPOR. Administration of a monoclonal anti-HMGB1 antibody after sepsis onset in mice partially restores EPO signaling in vivo. Thus, HMGB1-mediated restriction of EPO signaling contributes to the chronic phase of anemia of inflammation.

Using leave-one-out cross validation (LOO) in a multilevel regression and poststratification (MRP) workflow: A cautionary tale.

In recent decades, multilevel regression and poststratification (MRP) has surged in popularity for population inference. However, the validity of the estimates can depend on details of the model, and there is currently little research on validation. We explore how leave-one-out cross validation (LOO) can be used to compare Bayesian models for MRP. We investigate two approximate calculations of LOO: Pareto smoothed importance sampling (PSIS-LOO) and a survey-weighted alternative (WTD-PSIS-LOO). Using two simulation designs, we examine how accurately these two criteria recover the correct ordering of model goodness at predicting population and small-area estimands. Focusing first on variable selection, we find that neither PSIS-LOO nor WTD-PSIS-LOO correctly recovers the models' order for an MRP population estimand, although both criteria correctly identify the best and worst model. When considering small-area estimation, the best model differs for different small areas, highlighting the complexity of MRP validation. When considering different priors, the models' order seems slightly better at smaller-area levels. These findings suggest that, while not terrible, PSIS-LOO-based ranking techniques may not be suitable to evaluate MRP as a method. We suggest this is due to the aggregation stage of MRP, where individual-level prediction errors average out. We validate these results by applying to the real world National Health and Nutrition Examination Survey (NHANES) data in the United States. Altogether, these results show that PSIS-LOO-based model validation tools need to be used with caution and might not convey the full story when validating MRP as a method.

Updates on the use of neuromodulation in geriatric patients.

PURPOSE OF REVIEW: In light of the updated AUA/SUFU guidelines on the diagnosis and treatment of overactive bladder (OAB), increased utilization of advanced therapies is expected in the coming years. The primary aim of this review is to summarize existing outcome and safety data on the use of neuromodulation in geriatric patients, as well as highlight recent advances in neuromodulation that may be particularly advantageous in the geriatric population. RECENT FINDINGS: There are mixed data demonstrating efficacy of sacral neuromodulation by decade of life, with older individuals most often demonstrating lower odds of progressing to stage 2 implantation. However, a large majority of patients still undergo stage 2 implantation with no significant increase in complications reported when compared to younger cohorts. Neuromodulation is broadening to have wider indications outside of OAB, which may be particularly beneficial in the elderly population (fecal incontinence, nonobstructive urinary retention, and constipation). Posterior tibial nerve stimulation remains a well tolerated and efficacious treatment for OAB, with new FDA-approved implantable devices joining the commercial market, which may expand access for elderly populations. SUMMARY: The data are encouraging and support the use of neuromodulation in geriatric patients.

External Factors Influencing the Implementation of Policy, System, and Environmental Change Strategies Within Cooperative Extension.

Introduction. Multilevel approaches are important to promote the adoption of healthier practices at the individual and community levels. Cooperative Extension pairs policy, systems, and environmental (PSE) change approaches with direct education programs focused on individual and community health. This study sought to understand Family and Consumer Sciences (FCS) Extension agents' perceptions of PSE change supports, benefits for their communities, and resources and partnerships important for implementation. Method. The Consolidated Framework for Implementation Research was used to develop a survey to assess outer setting domains related to PSE work. In addition to close-ended questions, the survey included several open-ended, qualitative questions exploring the benefits, resources, and relationships required to implement PSE changes. The surveys were collected online from FCS agents in two states. Descriptive statistics were calculated, open responses were coded, and key themes were established. Results. FCS agents (n=116) indicated high levels of agreement about having necessary support from state-level specialists (71%) and the overall Extension organization (64%). The largest gaps in support were reported as grant or external funding sources, time, and county programming funds. Half of the sample agreed that PSE training was adequate, but only 38.5% reported previously participating in PSE-specific training. Open-ended question responses revealed diverse relationships and numerous benefits of PSE work, including more sustainable health behavior changes and greater local Extension visibility. Discussion. Our findings corroborate previous work and identify potential gaps that future interventions can address to better support Extension and public health professionals when implementing PSE work at the community level.

Monitoring Food Affordability: Reliability and Validity of an Online Nutritious Food Basket.

Purpose: This study aimed to assess the reliability and validity of an online approach to monitoring food affordability in Ontario using the updated Ontario Nutritious Food Basket (ONFB).Methods: The ONFB was priced online in 12 large multi-chain grocery stores to test intra-/inter-rater reliability using percent agreement and intra-class correlations (ICCs). Then, the ONFB was priced in-store and online in 28 stores to estimate food price differences using paired t-tests and Pearson's correlation for all (n =1708) and matched items (same product/brand and purchase unit) (n = 1134).Results: Intra-/inter-rater agreement was high (95.4%/81.6%; ICC = 0.972, F = 69.9, p < 0.001). On average, in-store prices were less than $0.02 lower than online prices. There were no significant differences between mean in-store and online prices for all items (t = 0.504 p = 0.614). The mean price was almost perfectly correlated between in-store and online (fully matched: R = 0.993 p < 0.001; all items: R = 0.967 p < 0.001). Online monthly ONFB estimates for a family of four were strongly correlated (R = 0.937 p < 0.001) with estimates calculated using in-store data.Conclusions: Online pricing is a reliable and valid approach to food costing in Ontario that contributes to modernizing the monitoring of food affordability in Canada and abroad.

"Quite simply they don't communicate": a case study of a National Health Service response to staff suicide.

Workplace suicide can have significant knock-on effects within an organisation, yet research has shown within the healthcare profession, not all staff receive suicide prevention training, and few employers take the time to reflect on the need to change workplace policies or practices following the death of a staff member to suicide. How staff suicide is communicated across an organisation and to family members is important. Effective crisis communication is critical for effective management for a timely and sensitive response to a staff suicide within an organisation. By doing so, workplaces can help to reduce the significant emotional trauma suicide can have on an employee, and support good mental health across its workforce. This study aimed to explore and understand the communication processes around staff suicide across a National Health Service (NHS) Trust and to provide recommendations based on these findings. Semi-structured interviews were conducted with 29 participants, each lasting approximately 90 min. The Consolidated Criteria for Reporting Qualitative Research (COREQ) guidelines were followed. Thematic analysis was used to analyse the data, resulting in seven themes being identified based on communication. Findings indicated that the Trust had no clear communication strategy in place for tackling staff suicide. Each suicide was handled differently, training across staff roles was lacking and operational procedures were deemed insensitive. This paper aimed to provide insight into the communication strategies used in the aftermath of a staff suicide. These findings highlight the inconsistency of the communication, lack of clear policy and guidance and the negative impact this had on staff. Further research is needed across NHS Trusts nationwide to gain insight into the current communication strategies in place to develop a national approach to clear communication following the death of an NHS worker to suicide. Tweetable abstract: Effective communication is critical in the aftermath of an NHS staff suicide. By doing so, NHS Trusts can help to reduce the trauma suicide can have on an employee and support good mental health across its workforce @stann2.

Persistence of Human Norovirus (GII) in Surface Water: Decay Rate Constants and Inactivation Mechanisms.

Human norovirus (HuNoV) is an important cause of acute gastroenteritis and can be transmitted by water exposures, but its persistence in water is not well understood. Loss of HuNoV infectivity in surface water was compared with persistence of intact HuNoV capsids and genome segments. Surface water from a freshwater creek was filter-sterilized, inoculated with HuNoV (GII.4) purified from stool, and incubated at 15 or 20 °C. We measured HuNoV infectivity via the human intestinal enteroid system and HuNoV persistence via reverse transcription-quantitative polymerase chain reaction assays without (genome segment persistence) or with (intact viral capsid persistence) enzymatic pretreatment to digest naked RNA. For infectious HuNoV, results ranged from no significant decay to a decay rate constant ("k") of 2.2 day-1. In one creek water sample, genome damage was likely a dominant inactivation mechanism. In other samples from the same creek, loss of HuNoV infectivity could not be attributed to genome damage or capsid cleavage. The range in k and the difference in the inactivation mechanism observed in water from the same site could not be explained, but variable constituents in the environmental matrix could have contributed. Thus, a single k may be insufficient for modeling virus inactivation in surface waters.

An Opportunity to Seize From Low Hanging Fruits: Capitalising on Incidentally Reported Coronary Artery Calcification.

AIM: We investigated the prevalence of incidental coronary artery calcifications (CAC) from non-electrocardiogram (ECG)-gated computed tomography (CT) chest (both contrast and non-contrast) for inpatients. We also assessed for downstream investigation and statin prescription from the inpatient teams. Incidental CAC are frequent findings on non-ECG-gated CT chest. It is associated with adverse prognosis in multiple patient cohorts. METHOD: All non-ECG-gated CT chest done as inpatients from a single centre referred from 1 January 2022 to 31 December 2022 with reported incidental CAC were reviewed for inclusion. Patients who had a history of known coronary artery disease, history of coronary stent or bypass, and presence of cardiac devices were excluded. RESULTS: Total of 123 patients were included, making the prevalence 6.2% (123/1,980). The median age is 76 years (interquartile range 69-85) and predominantly male at 54.5%. The majority of CT chest done were contrasted scans (91.1%). Only 26.8% of CAC were reported on severity with visual quantification, with 7.3% each reported for both moderate and severe CAC. Only 2.4% of CAC were reported in the conclusion of the CT report. Most of these patients were asymptomatic (34.1%). A total of 20.3% of patients had further tests done. Inpatient hospital mortality was 8.1%. About 23.6% and 34.1% of patients were on aspirin and statin therapy respectively at baseline. There was only 1 patient (1.2%) who was prescribed with new statin therapy on discharge. CONCLUSION: Incidental CAC is prevalent in inpatient settings and remains under-recognised by ordering clinicians, with low prescription rate of statin therapy. Practice-changing measures to standardise reporting of incidental CAC is needed to identify patients with subclinical coronary disease and initiate preventive interventions.

Estimating Relative Abundance of 2 SARS-CoV-2 Variants through Wastewater Surveillance at 2 Large Metropolitan Sites, United States.

Monitoring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) is critical for public health management of coronavirus disease. Sequencing is resource-intensive and incompletely representative, and not all isolates can be sequenced. Because wastewater SARS-CoV-2 RNA concentrations correlate with coronavirus disease incidence in sewersheds, tracking VOCs through wastewater is appealing. We developed digital reverse transcription PCRs to monitor abundance of select mutations in Alpha and Delta VOCs in wastewater settled solids, applied these to July 2020-August 2021 samples from 2 large US metropolitan sewersheds, and compared results to estimates of VOC abundance from case isolate sequencing. Wastewater measurements tracked closely with case isolate estimates (Alpha, rp 0.82-0.88; Delta, rp 0.97). Mutations were detected in wastewater even at levels <5% of total SARS-CoV-2 RNA and in samples available 1-3 weeks before case isolate results. Wastewater variant monitoring should be strategically deployed to complement case isolate sequencing.

Addressing Health Inequities: An Exploratory Assessment of Extension Educators' Perceptions of Program Demand for Diverse Communities.

Land grant universities are a key provider of community-based health promotion programs through the Cooperative Extension Service. However, Extension's current approach to addressing systemic social determinants of health is incomplete and inconsistent. The purpose of this study was to explore Extension health educators' perceptions of demand for health promotion programming targeting audiences most likely to experience health inequities. Health educators within 2 state Extension systems were invited to complete an online survey based on a capacity building model. Survey questions included rating perceptions of demand for programming for health disparate populations: low-income; Black and African American; Hispanic, Latino/a, Latinx; persons with disabilities; immigrants and refugees; and lesbian, gay, bisexual, and transgender. Analysis of variance and Bonferroni post hoc testing was used to determine differences in perceived demand between populations. Ninety-six educators completed the survey. Perceived demand for low-income population programming was significantly higher than for other populations. Perceived programming demand for immigrants and refugees and lesbian, gay, bisexual, and transgender people was significantly lower than for other populations. Individual and organizational-level factors, including racism and Extension's historical scope, likely contribute to the results. Engaging historically excluded Extension audiences requires time and resources to improve the Extension system and educator capacity for relationship building, trust building, and communication.

Peer training in surgery: The SSuRF model approach.

Surgical training traditionally has been afforded an apprenticeship model of learning but has since strived to become a structured programme of learning events and progress. Peer led training in an undergraduate course is increasingly utilised but its role in postgraduate/speciality training is not widely published. This paper reviews the historical roots of surgical training and current educational theories which underpin the proposal of a new tool, the SSuRF approach, an innovate aide memoire to assist peer led technical/operative surgical training with the hope that this approach will allow peers, especially those who do not have much formal educational training, to teach those junior using a structured format and document this within their workplace based assessment. This contrasts with the rather tick box exercise that it is currently, and hence may promote a deeper learning throughout the teaching experience.

Factors Associated with Musculoskeletal Injuries While Hiking with a Backpack at Philmont Scout Ranch.

INTRODUCTION: Participants at Philmont Scout Ranch embark on 12-d treks with pre-trek physical conditioning and medical clearance by their primary care physician. In this study, we investigated potential contributing factors to self-reported musculoskeletal injuries during a backpack trek. METHODS: This study was a prospective cohort study that used a 3-part survey administered to participants before, during, and after their trek from June through August 2019. Health history and demographic information were retrieved from each hiker's medical record. A logistic regression model was used to assess factors associated with injuries, and odds ratios and 95% confidence intervals were reported. RESULTS: There were 1206 individuals enrolled in this study, and none withdrew from participation. The median age of the participants was 17 y (interquartile range 15-47); 1130 were male, 75 were female, and 1 was of unknown sex. Injuries were reported by 7% (n=88) of participants while in the backcountry, with injuries occurring in various anatomic locations (knee, ankle, leg, foot, hand, arm). Participants without missing data (74%; n=897) were included in the logistical regression analysis to describe factors significantly associated with injury. Factors significantly associated with injury included greater backpack weight to body weight ratio, body mass index greater than 30 kg·m-2, and past injuries that required a doctor visit. CONCLUSIONS: Self-reported injuries while hiking at Philmont Scout Ranch are infrequent and do not often require evacuation or advanced medical care. Camp policies to maintain appropriate backpack weight and counseling of obese and previously injured individuals may mitigate injury occurrence.

Rasa3 regulates stage-specific cell cycle progression in murine erythropoiesis.

Inherited bone marrow failure syndromes (IBMFS) are heterogeneous disorders characterized by dysregulated hematopoiesis in various lineages, developmental anomalies, and predisposition to malignancy. The scat (severe combined anemia and thrombocytopenia) mouse model is a model of IBMFS with a phenotype of pancytopenia cycling through crises and remission. Scat carries an autosomal recessive missense mutation in Rasa3 that results in RASA3 mislocalization and loss of function. RASA3 functions as a Ras-GTPase activating protein (GAP), and its loss of function in scat results in increased erythroid RAS activity and reactive oxygen species (ROS) and altered erythroid cell cycle progression, culminating in delayed terminal erythroid differentiation. Here we sought to further resolve the erythroid cell cycle defect in scat through ex vivo flow cytometric analyses. These studies revealed a specific G0/G1 accumulation in scat bone marrow (BM) polychromatophilic erythroblasts and scat BM Ter119-/c-KIT+/CD71lo/med progenitors, with no changes evident in equivalent scat spleen populations. Systematic analyses of RNAseq data from megakaryocyte-erythroid progenitors (MEPs) in scat crisis vs. scat partial remission reveal altered expression of genes involved in the G1-S checkpoint. Together, these data indicate a precise, biphasic role for RASA3 in regulating the cell cycle during erythropoiesis with relevance to hematopoietic disease progression.

Challenges in Measuring the Recovery of SARS-CoV-2 from Wastewater.

Wastewater-based epidemiology is an emerging tool for tracking the spread of SARS-CoV-2 through populations. However, many factors influence recovery and quantification of SARS-CoV-2 from wastewater, complicating data interpretation. Specifically, these factors may differentially affect the measured virus concentration, depending on the laboratory methods used to perform the test. Many laboratories add a proxy virus to wastewater samples to determine losses associated with concentration and extraction of viral RNA. While measuring recovery of a proxy virus is an important process control, in this piece, we describe the caveats and limitations to the interpretation of this control, including that it typically does not account for losses during RNA extraction. We recommend reporting the directly measured concentration data alongside the measured recovery efficiency, rather than attempting to correct the concentration for recovery efficiency. Even though the ability to directly compare SARS-CoV-2 concentrations from different sampling locations determined using different methods is limited, concentration data (uncorrected for recovery) can be useful for public health response.

Sewage, Salt, Silica, and SARS-CoV-2 (4S): An Economical Kit-Free Method for Direct Capture of SARS-CoV-2 RNA from Wastewater.

Wastewater-based epidemiology is an emerging tool to monitor COVID-19 infection levels by measuring the concentration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater. There remains a need to improve wastewater RNA extraction methods' sensitivity, speed, and reduce reliance on often expensive commercial reagents to make wastewater-based epidemiology more accessible. We present a kit-free wastewater RNA extraction method, titled "Sewage, Salt, Silica and SARS-CoV-2" (4S), that employs the abundant and affordable reagents sodium chloride (NaCl), ethanol, and silica RNA capture matrices to recover sixfold more SARS-CoV-2 RNA from wastewater than an existing ultrafiltration-based method. The 4S method concurrently recovered pepper mild mottle virus (PMMoV) and human 18S ribosomal subunit rRNA, which have been proposed as fecal concentration controls. The SARS-CoV-2 RNA concentrations measured in three sewersheds corresponded to the relative prevalence of COVID-19 infection determined via clinical testing. Lastly, controlled experiments indicate that the 4S method prevented RNA degradation during storage of wastewater samples, was compatible with heat pasteurization, and in our experience, 20 samples can be processed by one lab technician in approximately 2 h. Overall, the 4S method is promising for effective, economical, and accessible wastewater-based epidemiology for SARS-CoV-2, providing another tool to fight the global pandemic.

Awareness and outcomes of the fruits and veggies (FNV) campaign to promote fruit and vegetable consumption among targeted audiences in California and Virginia: a cross-sectional study.

BACKGROUND: In 2015, the Partnership for a Healthier America launched the branded Fruits & Veggies (FNV) Campaign to apply a unique industry-inspired marketing approach to promote fruit and vegetable sales and intake to moms and teens in two US pilot markets: Fresno, California and Hampton Roads, Virginia. The aims of this cross-sectional study were to: 1) assess brand awareness and fruit- and vegetable-related outcomes among FNV Campaign target audiences in the California and Virginia market locations; and 2) examine whether reported awareness of the FNV Campaign was associated with differences in fruit- and vegetable-related cognitive and behavioral outcomes. METHODS: Data for this cross-sectional study were collected using an online survey administered to a non-probability convenience sample (n = 1604; February-July 2017) of youth aged 14-20 years (n = 744) and moms aged 21-36 years (n = 860) in the two pilot markets. Descriptive statistics were computed and outcomes compared between unaware and aware respondents, controlling for sociodemographic covariates. Multivariate analysis of covariance (MANCOVA) was conducted to assess whether fruit- and vegetable-related attitude, belief, and encouragement outcomes differed by FNV Campaign awareness; logistic regression was used to examine associations between FNV brand awareness and dichotomous variables (fruit- and vegetable-related behavioral intentions, trying new fruits and vegetables); and ANCOVA was used to assess associations with daily fruit and vegetable intake frequency. RESULTS: Approximately 20% (n = 315/1604) of respondents reported awareness of the FNV Campaign. Youth that reported awareness of the FNV Campaign (n = 167, 22.4%) had higher intentions to buy (p = 0.003) and eat (p = 0.009) fruits and vegetables than unaware respondents. Mothers that reported awareness of the FNV Campaign (n = 148, 17.2%) reported greater encouragement for friends and family to eat fruits and vegetables (p = 0.013) and were approximately 1.5 times more likely to report trying a new fruit or vegetable (p = 0.04) than mothers unaware of the Campaign. Daily fruit and vegetable intake frequency did not differ by Campaign awareness. CONCLUSIONS: FNV Campaign awareness was associated with limited but positive short- and intermediate-term cognitive and behavioral outcomes among target audience respondents. These findings can inform future research to enhance understanding and improve the FNV Campaign as it is expanded to new markets nationwide.

Red, Yellow, and Green Light Changes: Adaptations to Extension Health Promotion Programs.

Extension professionals have high autonomy to adapt the programs they deliver. However, fidelity is typically not reported, so it is unknown what adaptations are made. It is also unknown whether agents have the necessary training to adapt programs while maintaining fidelity to the core components. The purpose of this study was to determine (1) adaptations that Extension agents and specialists are making to programs they deliver, (2) the reasons for making these adaptations, (3) timing of adaptations, and (4) Extension agents' and specialists' understanding of the adaptation process. Extension agents and specialists nationwide were invited to complete a survey which queried about adaptations based on the traffic light model, adaptome, and adaptation taxonomy. Specifically, the traffic light model assigns a color for adaptations: tailoring language or pictures (green), adding/substituting activities or session sequence (yellow), or deleting lessons and decreasing timeline or session length (red). Responses were received from 98 agents and 24 specialists. Most agents and specialists reported making green (85% and 79%, respectively), yellow (89% and 75%), and red light changes (81% and 58%). Agents were significantly more likely than specialists to change the age appropriateness of lessons or activities, respond to individual client needs, substitute activities, delete lessons or activities, decrease the length and/or number of sessions, and shorten the program timeline. Within green light changes, each of those that could increase cultural appropriateness (tailoring language, scenarios, and pictures) were reported by less than 50% of agents and specialists. Of the most common adaptations reported, the primary reasons for these decisions were difficulty retaining or engaging participants and lack of time/competing demands on time. Most adaptations were made before the program was delivered. Agents rated their confidence level in the program adaptation process as somewhat confident to confident. Dissemination and implementation strategies to improve program adaptation within Extension are needed, including participatory approaches, training on the adaptation process, bi-directional evidence-based program repositories, and organizational-level changes.

Not every credible interval is credible: Evaluating robustness in the presence of contamination in Bayesian data analysis.

As Bayesian methods become more popular among behavioral scientists, they will inevitably be applied in situations that violate the assumptions underpinning typical models used to guide statistical inference. With this in mind, it is important to know something about how robust Bayesian methods are to the violation of those assumptions. In this paper, we focus on the problem of contaminated data (such as data with outliers or conflicts present), with specific application to the problem of estimating a credible interval for the population mean. We evaluate five Bayesian methods for constructing a credible interval, using toy examples to illustrate the qualitative behavior of different approaches in the presence of contaminants, and an extensive simulation study to quantify the robustness of each method. We find that the "default" normal model used in most Bayesian data analyses is not robust, and that approaches based on the Bayesian bootstrap are only robust in limited circumstances. A simple parametric model based on Tukey's "contaminated normal model" and a model based on the t-distribution were markedly more robust. However, the contaminated normal model had the added benefit of estimating which data points were discounted as outliers and which were not.

Temperature and particles interact to affect human norovirus and MS2 persistence in surface water.

Modeling the fate and transport of viruses and their genetic material in surface water is necessary to assess risks associated with contaminated surface waters and to inform environmental surveillance efforts. Temperature has been identified as a key variable affecting virus persistence in surface waters, but the effects of the presence of biological and inert particles and of their interaction with temperature have not been well characterized. We assessed these effects on the persistence of human norovirus (HuNoV) genotype II.4 purified from stool and MS2 in surface water. Raw or filter-sterilized creek water microcosms were inoculated and incubated in the dark at 10 °C, 15 °C, and 20 °C. HuNoV (i.e., genome segments and intact capsids) and MS2 (i.e., infectious MS2, genome segments, and intact capsids) concentrations were followed over 36 days. The range in positive, significant first-order decay rate constants for HuNoV in this study was 0.14 to 0.69 day-1 compared with 0.026 to 0.71 day-1 for that of MS2. Decay rate constants for HuNoV genome segments and infectious MS2 were largest in creek water that included biological and inert particles and incubated at higher temperatures. In addition, for HuNoV and MS2 incubated in raw or filter-sterilized creek water at 15 °C, capsid damage was not identified as a dominant inactivation mechanism. Environmental processes and events that affect surface water biological and inert particles, temperature, or both could lead to variable virus decay rate constants. Incorporating the effects of particles, temperature, and their interaction could enhance models of virus fate and transport in surface water.

You can bring plankton to fecal indicator organisms, but you cannot make the plankton graze: particle contribution to E. coli and MS2 inactivation in surface waters.

Organisms that are associated with feces ("fecal indicator organisms") are monitored to assess the potential for fecal contamination of surface water bodies in the United States. However, the effect of the complex mixtures of chemicals and the natural microbial community within surface water ("particles") on fecal indicator organism persistence is not well characterized. We aimed to better understand how particles, including biological (e.g., potential grazers) and inert (e.g., minerals) types, affect the fecal indicator organisms Escherichia coli K-12 ("E. coli") and bacteriophage MS2 in surface waters. A gradient of particles captured by a 0.2-µm-pore-size filter ("large particles") was generated, and the additional particles and dissolved constituents that passed through the filter were deemed "small particles." We measured the ratio of MS2 and E. coli that survived over a 24-h incubation period for each condition (0%-1,000% large-particle concentration in raw water) and completed a linear regression that included large- and small-particle coefficients. Particles were characterized by quantifying plankton, total bacterial cells, and total solids. E. coli and MS2 persistence was not significantly affected by large particles, but small particles had an effect in most waters. Small particles in higher-salinity waters had the largest, negative effect on E. coli and MS2 survival ratios: Significant small-particle coefficients ranged from -1.7 to -5.5 day-1 in the marine waters and -0.89 to -3.2 day-1 in the fresh and estuarine waters. This work will inform remediation efforts for impaired surface water bodies.IMPORTANCEMany surface water bodies in the United States have organisms associated with fecal contamination that exceed regulatory standards and prevent safe recreation. The process to remediate impaired water bodies is complicated because these fecal indicator organisms are affected by the local environmental conditions. For example, the effect of particles in surface water on fecal indicator concentrations are difficult to quantify in a way that is comparable between studies and water bodies. We applied a method that overcomes this limitation to assess the effects of large particles, including natural plankton that could consume the seeded fecal indicator organisms. Even in environmental water samples with diverse communities of plankton present, no effect of large particles on fecal indicator concentrations was observed. These findings have implications for the interpretation and design of future studies, including that particle characterization of surface water may be necessary to assess the fate of fecal indicators.