Comparison of virus aerosol concentrations across a face shield worn on a healthcare personnel during a simulated patient cough.

BACKGROUND: Patients diagnosed with coronavirus disease 2019 (COVID-19) aerosolize severe acute respiratory coronavirus virus 2 (SARS-CoV-2) via respiratory efforts, expose, and possibly infect healthcare personnel (HCP). To prevent transmission of SARS-CoV-2 HCP have been required to wear personal protective equipment (PPE) during patient care. Early in the COVID-19 pandemic, face shields were used as an approach to control HCP exposure to SARS-CoV-2, including eye protection. METHODS: An MS2 bacteriophage was used as a surrogate for SARS-CoV-2 and was aerosolized using a coughing machine. A simulated HCP wearing a disposable plastic face shield was placed 0.41 m (16 inches) away from the coughing machine. The aerosolized virus was sampled using SKC biosamplers on the inside (near the mouth of the simulated HCP) and the outside of the face shield. The aerosolized virus collected by the SKC Biosampler was analyzed using a viability assay. Optical particle counters (OPCs) were placed next to the biosamplers to measure the particle concentration. RESULTS: There was a statistically significant reduction (P < .0006) in viable virus concentration on the inside of the face shield compared to the outside of the face shield. The particle concentration was significantly lower on the inside of the face shield compared to the outside of the face shield for 12 of the 16 particle sizes measured (P < .05). CONCLUSIONS: Reductions in virus and particle concentrations were observed on the inside of the face shield; however, viable virus was measured on the inside of the face shield, in the breathing zone of the HCP. Therefore, other exposure control methods need to be used to prevent transmission from virus aerosol.

Evaluation of face shields used during aerosol generating procedures.

Transnasal flexible laryngoscopy is considered an aerosol generating procedure. A negative pressure face shield (NPFS) was developed to control aerosol from the patient during laryngoscopy. The purpose of this study was to determine the effectiveness of the NPFS at controlling virus aerosol compared to a standard disposable plastic face shield. The face shields were placed on a simulated patient coughing machine. MS2 bacteriophage was used as a surrogate for SARS-CoV-2 and was aerosolized using the coughing machine. The aerosolized virus was sampled on the inside and outside of the face shields. The virus aerosol concentration was not significantly different between the inside and outside of the traditional plastic face shield (p = 0.12). However, the particle concentrations across all particle sizes measured were significantly decreased outside the face shield. The virus and particle concentrations were significantly decreased (p < 0.01) outside the NPFS operating at a flow rate of 38.6 L per minute (LPM). When the NPFS was operated at 10 LPM, virus concentrations were not significantly different (p = 0.09) across the face shield. However, the number particle concentrations across all particle sizes measured were significantly different (p < 0.05).

Use of prototype side stream filtration system to control dust levels in a commercial swine farrowing building.

Swine meat provides an essential global food source. Due to economies of scale, modern U.S. swine production primarily occurs indoors to maintain an optimal environment across the stages of swine production. Indoor concentrations of dust and contaminant gases in swine production buildings increase in the winter months due to reduced ventilation to optimal building temperature. In this study, an engineering control technology designed to recirculate the air in a swine farrowing room through a mobile air handling unit containing high-efficiency particulate filters was presented. A mobile solution could be easily deployed as an intervention method if an infectious disease outbreak occurs at a swine operation. The performance of this control technology was evaluated following deployment in a production farrowing barn for a period of 6 weeks during the winter in the Midwestern United States. Contaminant concentrations of inhalable dust, respirable dust, and carbon dioxide were measured in the room treated by the prototype system and compared to contaminant concentrations measured in an untreated "control" room. Over 6 weeks, the mean inhalable and respirable dust concentrations observed during the study period for the "treatment" room were 2.61 and 0.14 mg/m3, respectively, compared to 3.51 and 0.25 mg/m3, respectively, for the control room. The mobile recirculating ventilation system, operating at a flow rate of 45 m3/min (5 room air exchanges per hour), reduced the inhalable dust by 25% and respirable dust by 48% as measured with a real-time aerosol monitor, when compared to the control room. In addition, no concentration differences in carbon dioxide and relative humidity between the treatment and the control rooms were observed. Inhalable and respirable concentrations of dust were significantly reduced (p = 0.001), which demonstrates an essential improvement of the air quality that may prove beneficial to reduce the burden of disease among both workers and animals.

Self-reported respiratory health symptoms and respiratory protection behaviors of young adult hog producers in the United States.

INTRODUCTION AND METHODS: In this study, we evaluated self-reported respiratory symptoms during agricultural work, respiratory protection use and experience, and perceived value of receiving respirators using Gear Up for Ag Health and Safety Program™ pre- and post-surveys from 703 to 212 young adult hog producers in the United States. To our knowledge, this is one of the most extensive survey data sets on self-reported respiratory symptoms and respiratory protection behaviors of collegiate-aged young adults working in US livestock production. RESULTS: About one-third (37%) of young adult hog producers stated that they have experienced cough, shortness of breath, fever, and chills after working in dusty areas on the farm. Most (76.2%) stated that they were already "always" or "sometimes" wearing filtering facepiece (N95-style) respirators, even before participating in an outreach program. About one-third (30%) reported experience wearing a cartridge-style respirator but only 5% reported having been fit-tested for a respirator. Young adult male producers were significantly more likely to report use of both respirator types when compared to females, both before and after the program. Male producers were also more likely than females to engage in high-risk farm tasks where respirators are recommended, such as cleaning out grain bins and mixing or grinding feed. Following an educational program, males and females reported using the respirators that they received at similar rates, and 20% of overall participants purchased additional respiratory protection. DISCUSSION: The study found that young adult hog producers in postsecondary education are already wearing respirators with some frequency and at rates higher than previously reported by agricultural workers. More research is needed to make effective task-based respirator-use recommendations and investigate some significant gender differences among young adult hog producers observed in this study.

Development of Shortened Enrichment Methods for Detection of Salmonella Typhimurium Spiked in Milk.

Rapid and accurate testing of pathogenic Salmonella enterica in dairy products could reduce the risk of exposure to the bacterial pathogens for consumers. This study aimed to reduce the assessment time needed for enteric bacteria recovery and quantification in food using the natural growth properties of Salmonella enterica Typhimurium (S. Typhimurium) in cow's milk and efficiently using rapid PCR methods. Over 5 h of 37 °C enrichment, culture and PCR methods measured increases in the non-heat-treated S. Typhimurium concentration at similar rates, with an average increase of 2.7 log10 CFU/mL between the start of enrichment and 5 h. In contrast, no bacteria were recovered by culture after S. Typhimurium in milk received heat treatment, and the number of gene copies of heat-treated Salmonella detected by PCR did not increase with the enrichment time. Thus, comparing culture and PCR data over just 5 h of enrichment time can detect and differentiate between replicating bacteria and dead bacteria.

Evaluation of aerosols in a simulated orthodontic debanding procedure.

Dental practitioners may be at risk for exposure to severe acute respiratory syndrome corona virus 2 when performing aerosol generating procedures. Though recent evidence suggests that coronavirus may be transmitted through aerosol generating procedures, it is unknown whether common procedures performed in dental clinics generate aerosol. The aim of this study was to simultaneously quantify airborne concentrations of the bacteriophage MS2 near the oral cavity of a dental mannequin and behind personal protective equipment (i.e., face shield) of the practitioner during a simulated orthodontic debanding procedure. A deband was performed eight times on a dental mannequin. Optical particle counters and SKC Biosamplers were used to measure particle concentration and to collect virus aerosol generated during the procedure, both near the oral cavity and behind the orthodontists face shield. A plaque assay was used to determine the viable virus airborne concentration. When comparing the two measuring locations, near the oral cavity and behind the clinician's face shield, there was no statistically significant difference of virus concentrations or particle size distribution. This study suggests that debanding under these conditions generates live virus aerosol and a face shield does not provide increased protection from virus aerosol, but does provide some protection against splatter during the procedure.

Preliminary investigation of a hypertonic saline nasal rinse as a hygienic intervention in dairy workers.

Livestock workers experience an increased burden of bioaerosol-induced respiratory disease including a high prevalence of rhinosinusitis. Dairy operations generate bioaerosols spanning the inhalable size fraction (0-100 µm) containing bacterial constituents such as endotoxin. Particles with an aerodynamic diameter between 10 and 100 µm are known to deposit in the nasopharyngeal region and likely affect the upper respiratory tract. We evaluated the effectiveness of a hypertonic saline nasal lavage in reducing inflammatory responses in dairy workers from a high-volume dairy operation. Inhalable personal breathing zone samples and pre-/post-shift nasal lavage samples from each participant over five consecutive days were collected. The treatment group (n = 5) received hypertonic saline while the control group (n = 5) received normotonic saline. Personal breathing zone samples were analyzed for particulate concentrations and endotoxin using gravimetric and enzymatic methods, respectively. Pro- and anti-inflammatory cytokines (i.e., IL-8, IL-10, and TNF-α) were measured from nasal lavage samples using a multiplex assay. Inhalable dust concentrations ranged from 0.15 to 1.9 mg/m3. Concentrations of both pro- and anti-inflammatory cytokines, specifically IL-6, IL-8, and IL-10, were significantly higher in the treatment group compared to the control group (p < 0.02, p < 0.04, and p < 0.01, respectively). Further analysis of IL-10 anti-inflammatory indicates a positive association between hypertonic saline administration and IL-10 production. This pilot study demonstrates that hypertonic saline nasal lavages were successful in upregulating anti-inflammatory cytokines to support larger interventional studies.

Safety Measures, Pesticide Concerns and Resources Utilized among Young Adult Workers: A Brief Report.

INTRODUCTION: Resources on pesticide information are widely available; however, little is known about the concerns young agricultural workers have about pesticides, whether they use existing resources to find information about pesticides, and how these resources influence safety behaviors such as personal protective equipment (PPE) use. OBJECTIVES: To examine demographic characteristics, safety measures, concerns about pesticide use and resources for pesticide information. METHODS: Young agricultural workers were recruited through three collegiate agricultural programs and completed an online questionnaire related to pesticide safety and use. RESULTS: Most participants who applied pesticides reported always wearing gloves (60.5%), using a tractor with an enclosed cab (68.4%), and always wearing long pants (76.3%). Among all participants, pesticide drift to crops (65.1%) and water contamination (62.3%) were the biggest concerns among young agricultural workers. The internet was the most utilized source to locate information about pesticides (76.4%), with the most common internet resources being online materials from universities or colleges (71.6%), the government (69.1%), or pesticide companies (66.7%). Accessibility (90.6%) and speed (78.3%) were the most common reasons for using the internet for information. Misinformation was the most common barrier (80.2%). CONCLUSIONS: Future studies should examine the accuracy and accessibility of pesticide information available on the internet since young adult workers rely on these resources for pesticide information.

Urban Particulate Matter Impairment of Airway Surface Liquid-Mediated Coronavirus Inactivation.

Air pollution particulate matter (PM) is associated with SARS-CoV-2 infection and severity, although mechanistic studies are lacking. We tested whether airway surface liquid (ASL) from primary human airway epithelial cells is antiviral against SARS-CoV-2 and human alphacoronavirus 229E (CoV-229E) (responsible for common colds), and whether PM (urban, indoor air pollution [IAP], volcanic ash) affected ASL antiviral activity. ASL inactivated SARS-CoV-2 and CoV-229E. Independently, urban PM also decreased SARS-CoV-2 and CoV-229E infection, and IAP PM decreased CoV-229E infection. However, in combination, urban PM impaired ASL's antiviral activity against both viruses, and the same effect occurred for IAP PM and ash against SARS-CoV-2, suggesting that PM may enhance SARS-CoV-2 infection.

Agricultural Cooperatives in Mental Health: Farmers' Perspectives on Potential Influence.

Agricultural cooperatives are formed to promote farmers' economic, social, and legislative interests. Their role in influencing mental health is less known. We characterized farmers' experiences with cooperatives and identified the potential impact of cooperatives in promoting mental health. Semi-structured interviews were conducted in Wisconsin with 12 participants, including farmers, cooperative professionals, and agricultural extension educators. Participants were asked about stress among farmers; cooperative structures and services provided to farmers, and farmers' interactions with the cooperatives; and the role cooperatives play in reducing stress among farmers. Three main themes were developed: stress farmers were experiencing, available resources from cooperatives, and the role of cooperatives in promoting farmers' mental health. Stress farmers were experiencing was elucidated through the subthemes: increased stress, depression, and suicide and stressors involving finances, occupational pressure, relationships, isolation, and loneliness. Available resources from cooperatives were described in subthemes: cooperative characteristics, services, and engagement activities. The role of cooperatives in promoting farmers' mental health was discussed through subthemes: responder, community, facilitator, and divergent views on whether co-ops can protect farmers' mental health. Cooperatives provide members market stability, services, and opportunities for decision-making, social interaction, and civic engagement. These resources create a community where farmers feel a sense of belonging and retain a level of control. As rural communities continue to struggle with mental health resource shortages, identifying and evaluating community-based resources such as those offered by the cooperatives is imperative.

Determination of murine norovirus aerosol concentration during toilet flushing.

Murine norovirus (MNV) was used as a surrogate for human viral pathogens (e.g., norovirus) to determine if toilet flushing resulted in the aerosolization of virus. A flushometer type toilet was seeded with a viral solution of 105 and 106 PFU mL-1 of MNV and then flushed. Upon flushing, two bioaerosol samplers were activated to collect aerosolized MNV. Prior to the experiment, two optical particle counters monitored particle size and number distribution of aerosol produced from flushing a toilet across height, position, and side. The location with the highest mean particle concentration, was behind the toilet and 0.15 m above the toilet bowl rim, which is where bioaerosol sampling occurred. Bioaerosol and toilet water samples were collected, extracted and then quantified using RT-ddPCR. The concentration of MNV collected after seeding the toilet water ranged from 2.18 × 105 to 9.65 × 106 total copies of MNV. Positive samples of airborne MNV were detected with collected concentrations ranging from 383 to 684 RNA copies/m3 of air. This study provides evidence that viral pathogens may be aerosolized when a toilet is flushed. Furthermore, the MNV used in this study is a model organism for human norovirus and may be generalizable to other viral pathogens (e.g., coronavirus). This study suggests that virus is aerosolized from toilet flushing and may contribute to human exposure to viral pathogens.

Examination of Symptoms of Depression among Cooperative Dairy Farmers.

Farmers experience a high risk of stress, depression, and suicide. Risk factors are well documented but protective factors are seldom examined. Social support has been reported to reduce psychological distress among the general population but its effect on farmers is inconclusive. Agricultural cooperatives are typically created and owned by farmers to secure markets, access supplies and services, and participate in decision-making. It is unknown whether having cooperative resources impacts symptoms of depression. A survey was used to examine whether having access to cooperative programs and social support impacted symptoms of depression among dairy farmers. Farm bankruptcies, stress, depression, and suicide were identified as ongoing concerns. Having social support and cooperative educational opportunities and mentorship programs were associated with decreased symptoms of depression. Conversely, having cooperative policy discussions was associated with increased symptoms of depression. Results suggest that social support can potentially reduce symptoms of depression among farmers and having access to cooperative resources can reduce or increase it, depending on the type of program. Our findings identified an opportunity to further examine how programs provided by farmer-led organizations such as cooperatives can impact stress, depression, and suicide among farmers.

Association of Exposure to Cattle with Self-Reported History of TB Among Dairy Workers.

BACKGROUND: Mycobacterium bovis (bTB) is a potential health hazard to dairy workers. This study uses the One Health wholistic framework for examining bovine tuberculosis (TB) and its relationship to human health. This approach can help bridge surveillance data gaps and contribute to disease control and prevention programs for dairy farm workers, cattle, and the environment. The primary objective of this study was to compare the self-reported history of TB among dairy workers in Bailey County, Texas, with occupational categories of risk and exposure to TB. METHODS: A cross-sectional study was conducted among dairy workers. Job positions were used as a proxy for exposure to cattle-high and medium/low. We employed bivariate analyses to examine differences between groups using both the chi-square test and the nonparametric Kruskal-Wallis test. RESULTS: Of the 293 dairy workers invited, 77.0% (n = 225) participated. No statistically significant associations were found between job categories and reported history of TB exposure. Workers in the high group were younger, Guatemalan males with lower levels of formal education, more likely to be single with no children, and cohabitating with coworkers compared with the medium/low group. CONCLUSION/APPLICATION TO PRACTICE: Self-reported TB history among dairy workers is an imprecise measure of being previously diagnosed with TB. Dairy workers at risk for occupationally acquired TB could be tested for TB before employment and tested periodically thereafter, and more expeditiously treated if a positive test is obtained. Future studies should focus on the feasibility of offering on-farm health services, such as TB screening.

Association of Category of Cattle Exposure with Tuberculosis Knowledge among Dairy Workers in Bailey County, Texas.

Objective: To determine the knowledge of tuberculosis (TB) among dairy workers in Bailey County, Texas.Methods: A cross-sectional study design was used to collect 225 survey responses concerning knowledge of TB among dairy workers on 10 dairy farms in Bailey County, Texas. Subjects used iPad tablets to log responses to 15 demographic questions and a 17-item TB knowledge quiz, measured by: (1) TB characteristics, (2) TB transmission, (3) TB symptoms, (4) TB diagnosis, (5) TB treatment, and (6) bovine TB. A proxy for exposure, dairy workers were classified into categories of cattle exposure - high, medium, and low.Results: Relative to the medium/low group, workers in the high group tended to be younger (32.6 (SD 11.0)), Guatemalan (52.6%), K'iche' speaking (37.8%), males (89.1%) with less years living in the U.S. (10.8 [SD 12.5]) and lower levels of formal education completed (59.6% with no formal/elementary level). Overall, the average score was 7.1 (SD 4.9) out of 17 (41.8% out of 100.0%). Relative to one another, the medium/low group (8.0 (SD 4.6) out of 17) scored better than the high group (6.7 [SD 5.1] out of 17). No significant associations were found between the category of exposure and TB knowledge score.Conclusion: Deficiencies in TB knowledge were identified in all categories of exposure. TB training on dairy farms should include all measured tested in this study and should be administered to all workers regardless of the category of exposure.

OSHA Voluntary Respirator Use: Challenges incurred with use of N95 filtering facepiece respirators during the COVID-19 pandemic.

This article discusses several lessons learned in dealing with the interpretation of the Occupational Health and Safety Administration (OSHA) Voluntary Use provision of the Respiratory Health Standard at health-care facilities during the COVID-19 pandemic in the United States. This includes (but is not limited to) (a) confusion about OSHA policy and procedures when health-care workers brought outside personal protective equipment (PPE; N95 filtering facepiece respirators) into the workplace; (b) challenges in adhering to guidelines stated in Appendix D of the Respiratory Protection Standard; (c) difficulty in achieving respirator fit testing for workers; and (d) vague or inconsistent determination of "non-hazardous" environments (concerning COVID-laden droplets and aerosols). The purpose was to identify gaps in knowledge to help policy makers, enforcement personnel, safety managers, and health-care workers in the United States prepare for similar future events involving PPE shortages.

Bovine Tuberculosis Case Intervention Using the T.SPOT.TB Assay to Screen Dairy Workers in Bailey County, Texas.

Background: One potential exposure on a dairy farm is Mycobacterium bovis or bovine tuberculosis (bTB)-an infectious zoonotic pathogen. The prevalence of tuberculosis among dairy workers in the U.S. is unknown largely due to insufficient surveillance and testing practices. Our objective was to determine the prevalence and risk factors of LTBI among dairy workers potentially exposed to cattle infected with bTB in two Bailey County, Texas dairy farms in 2016. Methods: This study involved a secondary analysis of data that were collected by Texas Department of State Health Services (DSHS) Public Health Region 1 (PHR 1). A total of 140 dairy workers were tested using the T.SPOT.TB test assay. As a proxy for occupational exposures, we used three categories of cattle exposure groups based on work task, duration, and conditions of exposure to cattle-high, medium, low. Results: Positive LTBI was found among 14/140 (10.0%) of the dairy workers tested with 12/87 (13.8%) in Dairy A and 2/53 (3.8%) in Dairy B. All LTBI cases were determined to be from Hispanic workers with 71.4% indicating having been vaccinated with the BCG vaccine in their country of birth and none indicated previously known exposure to TB. The high category of cattle exposure group experienced the highest prevalence of LTBI (64.3%), followed by the medium cattle exposure group (28.6%), and the low cattle exposure group (7.1%). Conclusion: Our findings suggest that the prevalence of LTBI among dairy workers in Bailey County, Texas is higher than demographically comparable workforces. Future efforts should focus on the development, delivery, and evaluation of a tuberculosis-and other zoonotic diseases-health and safety training which can become a part of a more comprehensive safety management and training program on dairy farms.

The Optimization of Methods for the Collection of Aerosolized Murine Norovirus.

Globally, norovirus is the most common gastroenteritis causing pathogen. Annually, norovirus causes 685 million cases of acute gastroenteritis and 200,000 deaths, worldwide. Recent evidence has suggested that norovirus can also be spread via aerosolization; however, an indoor generation source has yet to be determined. We optimized a sampling method for the collection of aerosolized norovirus using murine norovirus (MNV) as a surrogate. Optimization of the sampling method was performed using two bioaerosol samplers (SKC BioSampler and the NIOSH Bioaerosol Cyclone Sampler 251) and two sampling media (Hanks Balanced Salt Solution [HBSS] and Phosphate Buffered Saline [PBS]). Murine norovirus was aerosolized in a bioaerosol chamber and later collected using each sampler/media combination. Collected MNV was quantified using quantitative polymerase chain reaction (qPCR). Intact capsids of MNV were assessed using propidium monoazide dye in combination with qPCR and confirmed with transmission electron microscopy. Ten trials were conducted, with each trial lasting for 30 min. The SKC BioSampler collected a significantly higher concentration of MNV than the NIOSH-251 sampler did (p-value < 0.0001). However, there were no significant differences in the relative percent of MNV that remained viable between both samplers (p-value = 0.2215). The use of HBSS sampling media yielded a higher concentration of MNV than PBS media (p-value = 0.0125). However, PBS media maintained viability at a significantly higher percentage than HBSS media (p-value < 0.0001). The results support the optimization of a sampling method for the collection of aerosolized MNV and possibly norovirus in different sampling environments.

Bioaerosols generated from toilet flushing in rooms of patients with Clostridioides difficile infection.

BACKGROUND: Clostridioides difficile infection (CDI) is the most frequently reported hospital-acquired infection in the United States. Bioaerosols generated during toilet flushing are a possible mechanism for the spread of this pathogen in clinical settings. OBJECTIVE: To measure the bioaerosol concentration from toilets of patients with CDI before and after flushing. DESIGN: In this pilot study, bioaerosols were collected 0.15 m, 0.5 m, and 1.0 m from the rims of the toilets in the bathrooms of hospitalized patients with CDI. Inhibitory, selective media were used to detect C. difficile and other facultative anaerobes. Room air was collected continuously for 20 minutes with a bioaerosol sampler before and after toilet flushing. Wilcoxon rank-sum tests were used to assess the difference in bioaerosol production before and after flushing. SETTING: Rooms of patients with CDI at University of Iowa Hospitals and Clinics. RESULTS: Bacteria were positively cultured from 8 of 24 rooms (33%). In total, 72 preflush and 72 postflush samples were collected; 9 of the preflush samples (13%) and 19 of the postflush samples (26%) were culture positive for healthcare-associated bacteria. The predominant species cultured were Enterococcus faecalis, E. faecium, and C. difficile. Compared to the preflush samples, the postflush samples showed significant increases in the concentrations of the 2 large particle-size categories: 5.0 µm (P = .0095) and 10.0 µm (P = .0082). CONCLUSIONS: Bioaerosols produced by toilet flushing potentially contribute to hospital environmental contamination. Prevention measures (eg, toilet lids) should be evaluated as interventions to prevent toilet-associated environmental contamination in clinical settings.

Reliability of observational- and machine-based teat hygiene scoring methodologies.

Removal of teat-end debris is one of the most critical steps in the premilking process. We aimed to estimate inter- and intra-rater reliability of an observation-based rating scale of dairy parlor worker teat-cleaning performance. A nonrandom sample of 8 experienced raters provided teat swab debris ratings scored on a 4-point ordinal visual scale for 175 teat swab images taken immediately after teat cleaning and before milking unit attachment. To overcome the uncertainty associated with visual inspection and observation-based rating scales, we assessed the reliability of an automated observer-independent method to assess teat-end debris using digital image processing and machine learning techniques to quantify the type and amount of debris material present on each teat swab image. Cohen's kappa coefficient (κ) was used to assess inter-rater score agreement on 175 teat swab images, and the intraclass correlation coefficient was used to assess both intra-rater score agreement and machine reliability. The reliability of debris scoring of teat swabs by raters was low (overall κ = 0.43), whereas the machine-based rating system demonstrated near-perfect reliability (Pearson r > 0.99). Our findings suggest that machine-based rating systems of worker performance are much more reliable than observational-based methods when evaluating premilking teat cleanliness. Teat swab image analysis technology can be further developed for training and quality control purposes to enable more efficient, reliable, and independent feedback on worker milking performance. As automated technologies are becoming more popular on dairy farms, machine-based teat cleanliness scoring could also be incorporated into automated milking systems.

Bioaerosol concentrations generated from toilet flushing in a hospital-based patient care setting.

Background: In the United States, 1.7 million immunocompromised patients contract a healthcare-associated infection, annually. These infections increase morbidity, mortality and costs of care. A relatively unexplored route of transmission is the generation of bioaerosols during patient care. Transmission of pathogenic microorganisms may result from inhalation or surface contamination of bioaerosols. The toilet flushing of patient fecal waste may be a source of bioaerosols. To date, no study has investigated bioaerosol concentrations from flushing fecal wastes during patient care. Methods: Particle and bioaerosol concentrations were measured in hospital bathrooms across three sampling conditions; no waste no flush, no waste with flush, and fecal waste with flush. Particle and bioaerosol concentrations were measured with a particle counter bioaerosol sampler both before after a toilet flushing event at distances of 0.15, 0.5, and 1 m from the toilet for 5, 10, 15 min. Results: Particle concentrations measured before and after the flush were found to be significantly different (0.3-10 µm). Bioaerosol concentrations when flushing fecal waste were found to be significantly greater than background concentrations (p-value = 0.005). However, the bioaerosol concentrations were not different across time (p-value = 0.977) or distance (p-value = 0.911) from the toilet, suggesting that aerosols generated may remain for longer than 30 min post flush. Toilets produce aerosol particles when flushed, with the majority of the particles being 0.3 µm in diameter. The particles aerosolized include microorganisms remaining from previous use or from fecal wastes. Differences in bioaerosol concentrations across conditions also suggest that toilet flushing is a source of bioaerosols that may result in transmission of pathogenic microorganisms. Conclusions: This study is the first to quantify particles and bioaerosols produced from flushing a hospital toilet during routine patient care. Future studies are needed targeting pathogens associated with gastrointestinal illness and evaluating aerosol exposure reduction interventions.