Detection of Selected Equine Respiratory Pathogens in Stall Samples Collected at a Multi-Week Equestrian Show during the Winter Months.

The aim of this study was to use environmental sampling to determine the frequency of detection of selected equine respiratory viruses and bacteria in horses attending a multi-week equestrian show during the winter months. At four time points during showing, environmental sponge samples were collected from all stalls on the property and tested for the presence of equine herpesvirus-1 (EHV-1), EHV-2, EHV-4, equine influenza virus (EIV), equine rhinitis B virus (ERBV), Streptococcus equi ss. equi (S. equi), and S. equi ss. zooepidemicus (S. zooepidemicus) using real-time PCR (PCR). Environmental sponges were collected from all 53 barns by using one sponge for up to 10 stalls. Further, 2/53 barns were randomly selected for individual stall sampling in order to compare the results between individual and pooled stall samples. A total of 333/948 (35.13%, 95% CI 32.09-38.26%) pooled environmental stall sponges tested PCR-positive for at least one of the selected respiratory pathogens. Streptococcus zooepidemicus was the most commonly detected pathogen in pooled samples (28.69%, 95% CI 25.83-31.69%), followed by EHV-2 (14.45%, 95% CI 12.27-16.85%), EHV-4 (1.37%, 95% CI 0.73-2.33%), and a very small percentage of pooled stall sponges tested PCR-positive for EHV-1, ERBV, EIV, and S. equi. In individual samples, 171/464 (36.85%, 95% CI 32.45-41.42%) environmental stall sponges tested PCR-positive for at least one of the selected pathogens, following a similar frequency of pathogen detection as pooled samples. The detection frequency of true respiratory pathogens from environmental samples was higher during the winter months compared to previous studies performed during spring and summer, and this testing highlights that such pathogens circulate with greater frequency during the colder months of the year. The strategy of monitoring environmental stall samples for respiratory pathogens circumvents the often labor-intensive collection of respiratory secretions from healthy horses and allows for a more efficient assessment of pathogen buildup over time. However, environmental stall testing for respiratory pathogens should not replace proper biosecurity protocols, but it should instead be considered as an additional tool to monitor the silent circulation of respiratory pathogens in at-risk horses.

Molecular Monitoring of EHV-1 in Silently Infected Performance Horses through Nasal and Environmental Sample Testing.

While the main goal in the management of an EHM outbreak focuses on identifying early clinical disease in order to physically separate infected horses, little effort is placed towards monitoring healthy horses. The assumption that EHV-1 shedding parallels clinical disease is erroneous, as subclinical shedders have been shown to be actively involved in viral spread. In an attempt to document the frequency of EHV-1 shedders and their impact on environmental contamination, we collected nasal swabs from 231 healthy horses and 203 environmental samples for the testing of EHV-1 by qPCR. Six horses and 28 stalls tested qPCR-positive for EHV-1. There was no association in the EHV-1 qPCR-positive status between nasal and stall swabs. While testing nasal secretions of healthy at-risk horses can detect active shedding at a specific time point, the testing of stall swabs allows to assess the temporal EHV-1 shedding status of a horse. The study results highlight the risk of subclinical EHV-1 shedders and stalls occupied by these horses as sources of infection for susceptible horses. The testing of individual stalls for the presence of EHV-1 may be a more practical approach than the collection of individual nasal swabs for the monitoring and early detection of the circulating virus. The results also highlight the need to improve the cleanliness and disinfection of stalls utilized by performance horses during show events.

Evaluation of 1-dimensional nanomaterials release during electrospinning and thermogravimetric analysis.

The growing research interests with engineered nanomaterials in academic laboratories and manufacturing facilities pose potential safety risks to students and workers. New nanoparticle substances, compositions, and processing approaches are developed regularly, creating new health risks which may not have been addressed previously. Accordingly, the Institute of Occupational Medicine conducted field studies at Texas A&M University (TAMU) to characterize possible particle emissions during processing and fabrication of carbon nanotubes, copper nanowires, and polymeric fibers. The nature of the monitoring work carried out at TAMU was to investigate the potential release of 1D nanomaterials to air from activities associated with synthesis, handling, thermal gravimetric analysis, and electrospinning processes, and evaluate the effectiveness of the utilized control measures. The potential nanoparticle release to air from each activity was investigated using a combination of particle detection instrumentations, coupled with standard filter-based sampling techniques. The analyses indicated that a measurable quantity of free carbon nanosphere aggregates was detected during these activities; however, no free MWCNTs or nanowires were detected. Scanning electron microscopy identified the presence of carbon nanospheres aggregates on the filters. While the control measures used at TAMU are effective in containing the nanomaterial release during processing, poor handling and occupational hygiene practices can increase the risk of employee exposure to the nanomaterials.

Physiologically-based pharmacokinetic and toxicokinetic models for estimating human exposure to five toxic elements through oral ingestion.

Biological monitoring and physiologically-based pharmacokinetic (PBPK) modelling are useful complementary tools in quantifying human exposure to elements in the environment. In this work, we used PBPK models to determine the optimal time for collecting biological samples in a longitudinal study to determine if participants who consumed allotment produce had been exposed to arsenic, cadmium, chromium, nickel or lead. There are a number of PBPK models for these elements published in the literature, which vary in size, complexity and application, given the differences in physiochemical properties of the elements, organs involved in metabolism and exposure pathways affected. We selected PBPK models from the literature to simulate the oral ingestion pathway from consumption of allotment produce. Some models required modification by reducing or removing selected compartments whilst still maintaining their original predictability. The performance of the modified models was evaluated by comparing the predicted urinary and blood elemental levels with experimental data and other model simulations published in the literature. Overall, the model predictions were consistent with literature data (r > 0.7, p < 0.05), and were influential in predicting when samples should be collected. Our results demonstrate the use of mathematical modelling in informing and optimising the design of longitudinal studies.

Review on the Processing and Properties of Polymer Nanocomposites and Nanocoatings and Their Applications in the Packaging, Automotive and Solar Energy Fields.

For the last decades, nanocomposites materials have been widely studied in the scientific literature as they provide substantial properties enhancements, even at low nanoparticles content. Their performance depends on a number of parameters but the nanoparticles dispersion and distribution state remains the key challenge in order to obtain the full nanocomposites' potential in terms of, e.g., flame retardance, mechanical, barrier and thermal properties, etc., that would allow extending their use in the industry. While the amount of existing research and indeed review papers regarding the formulation of nanocomposites is already significant, after listing the most common applications, this review focuses more in-depth on the properties and materials of relevance in three target sectors: packaging, solar energy and automotive. In terms of advances in the processing of nanocomposites, this review discusses various enhancement technologies such as the use of ultrasounds for in-process nanoparticles dispersion. In the case of nanocoatings, it describes the different conventionally used processes as well as nanoparticles deposition by electro-hydrodynamic processing. All in all, this review gives the basics both in terms of composition and of processing aspects to reach optimal properties for using nanocomposites in the selected applications. As an outlook, up-to-date nanosafety issues are discussed.

Nanoscale reference materials for environmental, health and safety measurements: needs, gaps and opportunities.

The authors critically reviewed published lists of nano-objects and their physico-chemical properties deemed important for risk assessment and discussed metrological challenges associated with the development of nanoscale reference materials (RMs). Five lists were identified that contained 25 (classes of) nano-objects; only four (gold, silicon dioxide, silver, titanium dioxide) appeared on all lists. Twenty-three properties were identified for characterisation; only (specific) surface area appeared on all lists. The key themes that emerged from this review were: 1) various groups have prioritised nano-objects for development as "candidate RMs" with limited consensus; 2) a lack of harmonised terminology hinders accurate description of many nano-object properties; 3) many properties identified for characterisation are ill-defined or qualitative and hence are not metrologically traceable; 4) standardised protocols are critically needed for characterisation of nano-objects as delivered in relevant media and as administered to toxicological models; 5) the measurement processes being used to characterise a nano-object must be understood because instruments may measure a given sample in a different way; 6) appropriate RMs should be used for both accurate instrument calibration and for more general testing purposes (e.g., protocol validation); 7) there is a need to clarify that where RMs are not available, if "(representative) test materials" that lack reference or certified values may be useful for toxicology testing and 8) there is a need for consensus building within the nanotechnology and environmental, health and safety communities to prioritise RM needs and better define the required properties and (physical or chemical) forms of the candidate materials.

Nano-TiO2--feasibility and challenges for human health risk assessment based on open literature.

This study aims at investigating feasibility and challenges associated with conducting a human health risk assessment for nano-titanium-dioxide (nano-TiO2) based on the open literature by following an approach similar to a classical regulatory risk assessment. Gaps in the available data set, both in relation to exposures and hazard, do not allow reaching any definite conclusions that could be used for regulatory decision-making. Results show that repeated inhalation in the workplace and possibly consumer inhalation may cause risks. Also short-term inhalation following spray applications may cause risks. Main future work should focus on generating occupational and consumer inhalation exposure data, as well as toxicity data on absorption following inhalation, repeated dermal contact, and contact with damaged skin. Also relevant seems further information on possible neurotoxicity and genotoxicity/carcinogenicity, as well as establishing a No Observed Adverse Effect Level (NOAEL) for acute inhalation of nano-TiO2.

A critical review of the biological mechanisms underlying the in vivo and in vitro toxicity of carbon nanotubes: The contribution of physico-chemical characteristics.

This critical review of the available human health safety data, relating to carbon nanotubes (CNTs), was conducted in order to assess the risks associated with CNT exposure. Determining the toxicity related to CNT exploitation is of great relevance and importance due to the increased potential for human exposure to CNTs within occupational, environmental and consumer settings. When this information is combined with knowledge on the likely exposure levels of humans to CNTs, it will enable risk assessments to be conducted to assess the risks posed to human health. CNTs are a diverse group of materials and vary with regards to their wall number (single and multi-walled CNTs are evident), length, composition, and surface chemistry. The attributes of CNTs that were identified as being most likely to drive the observed toxicity have been considered, and include CNT length, metal content, tendency to aggregate/agglomerate and surface chemistry. Of particular importance, is the contribution of the fibre paradigm to CNT toxicity, whereby the length of CNTs appears to be critical to their toxic potential. Mechanistic processes that are critical to CNT toxicity will also be discussed, with the findings insinuating that CNTs can exert an oxidative response that stimulates inflammatory, genotoxic and cytotoxic consequences. Consequently, it may transpire that a common mechanism is responsible for driving CNT toxicity, despite the fact that CNTs are a diverse population of materials. The similarity of the structure of CNTs to that of asbestos has prompted concern surrounding the exposure of humans, and so the applicability of the fibre paradigm to CNTs will be evaluated. It is also necessary to determine the systemic availability of CNTs following exposure, to determine where potential targets of toxicity are, and to thereby direct in vitro investigations within the most appropriate target cells. CNTs are therefore a group of materials whose useful exploitable properties prompts their increased production and utilization within diverse applications, so that ensuring their safety is of vital importance.

Nano-silver - feasibility and challenges for human health risk assessment based on open literature.

This study aims at investigating feasibility and challenges associated with conducting a human health risk assessment for nano-silver based on the open literature by following an approach similar to a classical regulatory risk assessment. Gaps in the available data set, both in relation to exposures and hazard, do not allow reaching any definite conclusions that could be used for regulatory decision making. Results show that repeated inhalation in the workplace and possibly consumer inhalation may cause risks. Also (uncontrolled) nano-silver drug intake and burn treatment of large parts of the body with wound dressings may cause risks. Main future work should focus on generating occupational and consumer exposure data, as well as toxicity data on absorption (are particles or only ions absorbed?), information on genetoxicity, and further information on the toxicity following inhalation exposure to sizes and agglomeration states as uncounted in the workplace.

A review of the in vivo and in vitro toxicity of silver and gold particulates: particle attributes and biological mechanisms responsible for the observed toxicity.

This review is concerned with evaluating the toxicity associated with human exposure to silver and gold nanoparticles (NPs), due to the relative abundance of toxicity data available for these particles, when compared to other metal particulates. This has allowed knowledge on the current understanding of the field to be gained, and has demonstrated where gaps in knowledge are. It is anticipated that evaluating the hazards associated with silver and gold particles will ultimately enable risk assessments to be completed, by combining this information with knowledge on the level of human exposure. The quantity of available hazard information for metals is greatest for silver particulates, due to its widespread inclusion within a number of diverse products (including clothes and wound dressings), which primarily arises from its antibacterial behaviour. Gold has been used on numerous occasions to assess the biodistribution and cellular uptake of NPs following exposure. Inflammatory, oxidative, genotoxic, and cytotoxic consequences are associated with silver particulate exposure, and are inherently linked. The primary site of gold and silver particulate accumulation has been consistently demonstrated to be the liver, and it is therefore relevant that a number of in vitro investigations have focused on this potential target organ. However, in general there is a lack of in vivo and in vitro toxicity information that allows correlations between the findings to be made. Instead a focus on the tissue distribution of particles following exposure is evident within the available literature, which can be useful in directing appropriate in vitro experimentation by revealing potential target sites of toxicity. The experimental design has the potential to impact on the toxicological observations, and in particular the use of excessively high particle concentrations has been observed. As witnessed for other particle types, gold and silver particle sizes are influential in dictating the observed toxicity, with smaller particles exhibiting a greater response than their larger counterparts, and this is likely to be driven by differences in particle surface area, when administered at an equal-mass dose. A major obstacle, at present, is deciphering whether the responses related to silver nanoparticulate exposure derive from their small size, or particle dissolution contributes to the observed toxicity. Alternatively, a combination of both may be responsible, as the release of ions would be expected to be greater for smaller particles.

Identification of the mechanisms that drive the toxicity of TiO(2 )particulates: the contribution of physicochemical characteristics.

This review focuses on outlining the toxicity of titanium dioxide (TiO(2)) particulates in vitro and in vivo, in order to understand their ability to detrimentally impact on human health. Evaluating the hazards associated with TiO(2 )particles is vital as it enables risk assessments to be conducted, by combining this information with knowledge on the likely exposure levels of humans. This review has concentrated on the toxicity of TiO(2), due to the fact that the greatest number of studies by far have evaluated the toxicity of TiO(2), in comparison to other metal oxide particulates. This derives from historical reasons (whereby the size dependency of particulate toxicity was first realised for TiO(2)) and due to its widespread application within consumer products (such as sunscreens). The pulmonary and dermal hazards of TiO(2 )have been a particular focus of the available studies, due to the past use of TiO(2 )as a (negative) control when assessing the pulmonary toxicity of particulates, and due to its incorporation within consumer products such as sunscreens. Mechanistic processes that are critical to TiO(2 )particulate toxicity will also be discussed and it is apparent that, in the main, the oxidant driven inflammatory, genotoxic and cytotoxic consequences associated with TiO(2 )exposure, are inherently linked, and are evident both in vivo and in vitro. The attributes of TiO(2 )that have been identified as being most likely to drive the observed toxicity include particle size (and therefore surface area), crystallinity (and photocatalytic activity), surface chemistry, and particle aggregation/agglomeration tendency. The experimental set up also influences toxicological outcomes, so that the species (or model) used, route of exposure, experiment duration, particle concentration and light conditions are all able to influence the findings of investigations. In addition, the applicability of the observed findings for particular TiO(2 )forms, to TiO(2 )particulates in general, requires consideration. At this time it is inappropriate to consider the findings for one TiO(2 )form as being representative for TiO(2 )particulates as a whole, due to the vast number of available TiO(2 )particulate forms and large variety of potential tissue and cell targets that may be affected by exposure. Thus emphasising that the physicochemical characteristics are fundamental to their toxicity.