Suchergebnisse

AbstractIn the U.S., spray irrigation is the most common method used in agriculture and supplementing with animal wastewater has the potential to reduce water demands. However, this could expose individuals to respiratory pathogens such as Legionella pneumophila and nontuberculosis Mycobacteria (NTM). Disinfection with methods like anaerobic digestion is an option but can increase concentrations of cytotoxic ammonia (personal communication). Our study aimed to model the annual risks of infection from these bacterial pathogens and the air concentrations of ammonia and determine if anaerobically digesting this wastewater is a safe option. Air dispersion modeling, conducted in AERMOD, generated air concentrations of water during the irrigation season (May–September) for the years 2013–2018. These values fed into the quantitative microbial risk assessments for the bacteria and allowed calculation of ammonia air concentrations. The outputs of these models were compared to the safety thresholds of 10−4 infections/year and 0.5 mg/m3, respectively, to determine their potential for negative health outcomes. It was determined that infection from NTM was not a concern for individuals near active spray irrigators, but that infection with L. pneumophila could be a concern, with a maximum predicted annual risk of infection of 3.5 × 10−3 infections/year and 25.2% of parameter combinations exceeding the established threshold. Ammonia posed a minor risk, with 1.5% of parameter combinations surpassing the risk threshold of 0.5 mg/m3. These findings suggest that animal wastewater should be anaerobically digested prior to use in irrigation to remove harmful pathogens.

AbstractEnteric viruses are often detected in water used for crop irrigation. One concern is foodborne viral disease via the consumption of fresh produce irrigated with virus‐contaminated water. Although the food industry routinely uses chemical sanitizers to disinfect post‐harvest fresh produce, it remains unknown how sanitizer and fresh produce properties affect the risk of viral illness through fresh produce consumption. A quantitative microbial risk assessment model was conducted to estimate (i) the health risks associated with consumption of rotavirus (RV)‐contaminated fresh produce with different surface properties (endive and kale) and (ii) how risks changed when using peracetic acid (PAA) or a surfactant‐based sanitizer. The modeling results showed that the annual disease burden depended on the combination of sanitizer and vegetable type when vegetables were irrigated with RV‐contaminated water. Global sensitivity analyses revealed that the most influential factors in the disease burden were RV concentration in irrigation water and postharvest disinfection efficacy. A postharvest disinfection efficacy of higher than 99% (2‐log10) was needed to decrease the disease burden below the World Health Organization (WHO) threshold, even in scenarios with low RV concentrations in irrigation water (i.e., river water). All scenarios tested here with at least 99.9% (3‐log10) disinfection efficacy had a disease burden lower than the WHO threshold, except for the endive treated with PAA. The disinfection efficacy for the endive treated with PAA was only about 80%, leading to a disease burden 100 times higher than the WHO threshold. These findings should be considered and incorporated into future models for estimating foodborne viral illness risks.

International service learning (ISL) programs seek to facilitate community inclusion, but such participation can prove elusive. For technical projects, such ventures can undermine local leadership, generate mistrust in communities, and even create an aversion to technological solutions. In this article, we document how social work and engineering students collaborated to bring clean water to rural Guatemala, and demonstrate how we employed social work principles to address the myriad issues encountered in the project. We contend that the inclusion of a social work perspective, with its emphasis on relationships, can help mitigate some of the challenges ISL projects tend to encounter.

15 pags, 8 figs ; Murine adenovirus 2 (MAdV-2) infects cells of the mouse gastrointestinal tract. Like human adenoviruses, it is a member of the genus Mastadenovirus, family Adenoviridae. The MAdV-2 genome has a single fibre gene that expresses a 787 residue-long protein. Through analogy to other adenovirus fibre proteins, it is expected that the carboxy-terminal virus-distal head domain of the fibre is responsible for binding to the host cell, although the natural receptor is unknown. The putative head domain has little sequence identity to adenovirus fibres of known structure. In this report, we present high-resolution crystal structures of the carboxy-terminal part of the MAdV-2 fibre. The structures reveal a domain with the typical adenovirus fibre head topology and a domain containing two triple ß-spiral repeats of the shaft domain. Through glycan microarray profiling, saturation transfer difference nuclear magnetic resonance spectroscopy, isothermal titration calorimetry and site-directed mutagenesis, we show that the fibre specifically binds to the monosaccharide N-acetylglucosamine (GlcNAc). The crystal structure of the complex reveals that GlcNAc binds between the AB and CD loops at the top of each of the three monomers of the MAdV-2 fibre head. However, infection competition assays show that soluble GlcNAc monosaccharide and natural GlcNAc-containing polymers do not inhibit infection by MAdV-2. Furthermore, site-directed mutation of the GlcNAc-binding residues does not prevent the inhibition of infection by soluble fibre protein. On the other hand, we show that the MAdV-2 fibre protein binds GlcNAc-containing mucin glycans, which suggests that the MAdV-2 fibre protein may play a role in viral mucin penetration in the mouse gut. ; This research was sponsored by grant BFU2014-53425-P (to M. J. v. R.), coordinated grants CTQ2015-64597-P-C02-01 and CTQ2015-64597-P-C02-02 (to J. J. B. and F. J. C., respectively), grant BFU2015-70052-R (to M. M.) and the Spanish Adenovirus Network (AdenoNet, BIO2015-68990-REDT), all from the Spanish Agencia Estatal de Investigación. Financial support to M. M. from the CIBER of Respiratory Diseases (CIBERES) from the Spanish Institute of Health Carlos III is also acknowledged. These grants are co-financed by the European Regional Development Fund of the European Union. A. K. S. and T. H. N. were recipients of pre-doctoral fellowships from La Caixa and CSIC-VAST, respectively. The expression vectors were designed and created in Hungary, and this was financed by the Hungarian Scientific Research Fund (OTKA K100163). M. K. thanks Enterprise Ireland for a Commercialisation Fund grant (CF/2015/0089), A. K. acknowledges the National University of Ireland for a Cancer Care West Hardiman PhD scholarship and L. J. acknowledges the EU FP7 programme in support of the GlycoHIT consortium (grant no. 260600). This work was supported by R01 AI104920 (to J. G. S.) from the National Institute for Allergy and Infectious Diseases (www.niaid.nih.gov). S. S. W. was also supported by the Helen Riaboff Whiteley Endowment to the University of Washington and by Public Health Service, National Research Service Awards T32 AI083203 from the National Institute for Allergy and Infectious Diseases and T32 GM007270 from the National Institute of General Medical Sciences.