Water wash personal decontamination effectiveness to reduce biological surrogate MS2 virus aerosol risk from shaken military uniform fabric

Proposed regulations by the U.S. Department of Energy have spurred development of energy‐efficient washing machines that utilize less water and operate with lower energy requirements than conventional machines. As a result, major changes in washing machine design are required. Among expected changes are increased use of a horizontal‐axis wash tub, an increase in fabric‐to‐wash liquor ratio, greater surfactant concentration in the wash water, and reduced average washing temperatures. As a result, surfactants used in future detergent formulations will be required to clean effectively in this new regime while producing minimal foam. Detergency test methods utilizing radiotracer techniques have been developed to study the detergency process in energy‐efficient washing machines. Detergency and redeposition of radiolabeled oily soils can be determined in a full‐size horizontal‐axis washing machine through scintillation counting of wash and rinse water samples. Measurements can be made after each wash process step and combined to determine total cycle detergency. This is a distinct advantage over conventional reflectance detergency methods where only total detergency at the end of the entire washing and rinsing process can be conveniently measured. Also, in contrast to indirect reflectance methods, measurements of absolute soil removal are obtained with the radiotracer method. In this study, soil redeposition was determined by measuring residual radioactivity on fabric swatches and then performing a material balance on the oily soil.

Characterization of aerosol emissions from CO2 capture plants treating various power plant and industrial flue gases

: The present study sought to evaluate the survival of selected bacterial and viral bio-threat agents in disinfected water. Water matrices tested included formulated tap water with and without chlorine for bacterial agents and formulated tap water with and without chlorine and bromine for viral agents. Agents tested included B. anthracis, Y. pestis, F. tularensis, Brucella spp., vaccinia virus, and Venezuelan equine encephalitis (VEE) virus. Disinfected water samples were spiked with each agent separately to a final concentration of approximately 1 x 10(exp 6) CFU or PFU/mL, and survival was assessed by serial dilution and plating or plaque assay. All agents were killed within minutes by the disinfectants tested with the exception of spores that required a longer contact time for inactivation. In conclusion, these results demonstrate that chlorine and bromine are effective disinfectants against agents tested.

15 - Commercial and novel solutions for fresh produce safety

Recent work on the use of seven‐component, doubly labeled radioactive soil to evaluate deter‐gency has depended on the analyses of the fabric for residual soil. Because of the variation of soil concentration within and between fabric swatches, considerable replication was required to lower the standard deviations to ±10%. A method for the analysis of wash water has been developed which requires much less replica‐tion and achieves higher precision (<±2%). The method is based on the use of an inhomo‐geneous scintillator, which can emulsify, or at least suspend, large volumes of water in a liquid scintillator while maintaining good counting efficiency. Studies of closure, i.e., amount of soil recovered in wash water plus fabric compared with soil introduced into the Tergotometer, have demonstrated that the method is reasonably accurate and quite precise.

Field Measurement of Amine Aerosol by FTIR and Phase Doppler Interferometry

Interventions to improve water quality, particularly when deployed at the household level, are an effective means of preventing endemic diarrhoeal disease, a leading cause of mortality and morbidity. Following a national survey indicating widespread faecal contamination of drinking water in Indian cities, a point-of-use water treatment unit was developed, which combines filtration and disinfection, does not require power or water pressure and has an operating cost of Rs. 0.25 (US$0.0057) per litre. We assessed the microbiological performance of the unit in the laboratory over the full 1500 l design life of the unit's consumable components. Geometric mean reductions for the units were more than 6 logs (99.9999%) for bacteria, more than 7 logs (99.99999%) for viruses and more than 3 logs (99.9%) for the test surrogate for protozoan cysts. Geometric mean reductions exceeded levels established for microbial water purifiers. The product water was free of detectable chlorine. If these results are validated in field trials, the deployment of the unit on a wide scale among vulnerable populations may make an important contribution to public health efforts to control intractable waterborne diseases.

Protecting civilian and military water supplies has received more attention since the United States began its war on terror in 2001. Both chlorine and bromine are used by branches of the U.S. military for disinfecting water supplies; however, limited data exists as to the effectiveness of these additives when used against viral biowarfare agents. The present study sought to evaluate the survival of selected viral biothreat agents in disinfected water. Disinfected water samples were spiked with vaccinia virus strain WR and Venezuelan equine encephalitis (VEE) virus strain TC-83 each separately to a final concentration of approximately 1 × 106 PFU/mL, and survival was assessed by plaque assay. Both viruses were inactivated by 1 mg/L free available chlorine (FAC) and 2mg/L total bromine within one hour. In conclusion, these results demonstrate that both chlorine and bromine are effective disinfectants against vaccinia virus and VEE strain TC-83 at the concentrations tested.

Viruses, including human pathogenic viruses, can persist in water. For producing drinking water from surface water via bank filtration, natural attenuation capacities and the fate of viruses during the passage of aquatic sediments are of particular interest. Moreover, the increasing frequency of extreme hydrological events necessitate re-evaluation of the sustainability and efficacy of processes removing viruses. For this purpose, we performed bank sediment filtration experiments using a mesocosm in a technical-scale experimental facility that simulates a field situation under more tightly controlled conditions. We used the bacteriophage MS2 as a surrogate for enteric viruses to study the transport of different viral loads through the bank sediment. Additionally, we simulated a heavy rain event to investigate the re-mobilization of initially attached virus particles. We quantified the abundance of infectious MS2 phages by plaque assay and the total number of MS2 particles by qPCR. Also, we differentiated pore water concentrations by depths of the sediment column and investigated attachment to the sediment matrix at the end of the individual experimental phases. Bank filtration over a vertical distance of 80 cm through sandy sediment revealed a virus removal efficiency of 0.8 log10 for total MS2 particles and 1.7 log10 for infectious MS2 particles, with an initial phage concentration of 1.84 × 108 gene copies mL−1. A low load of infectious MS2 (1.9 × 106 plaque forming units mL−1) resulted in a greater removal efficiency (3.0 log10). The proportion of infectious MS2 phages of the total MS2 particle mass steadily decreased over time, i.e., in the course of individual breakthrough curves and with sediment depth. The simulated pulse of rainwater caused a front of low ionic strength water which resulted in pronounced phage remobilization. The high proportion of infectious MS2 among the detached phages indicated that attachment to the sediment matrix may substantially conserve virus infectivity. Therefore, the re-mobilization of previously attached viruses owing to hydrological extremes should be considered in water quality assessment and monitoring schemes.

Efficient measurement of airborne viable viruses using the growth-based virus aerosol concentrator with high flow velocities

The pursuit of disinfecting porous materials or fomites to inactivate viral agents has special challenges. To address these challenges, a highly portable chlorine dioxide (ClO2) gas generation system was used to ascertain the ability of a gaseous preparation to inactivate a viral agent, the MS2 bacteriophage, when associated with potentially porous fomites of cloth, paper towel, and wood. The MS2 bacteriophage is increasingly used as a model to identify means of inactivating infectious viral agents of significance to humans. Studies showed that MS2 bacteriophage can be applied to and subsequently recovered from potential porous fomites such as cloth, paper towel, and wood. Paired with viral plaque assays, this provided a means for assessing the ability of gaseous ClO2 to inactivate bacteriophage associated with the porous materials. Notable results include 100% inactivation of 6 log bacteriophage after overnight exposure to 20 parts per million(ppm) ClO2. Reducing exposure time to 90 minutes and gas ppm to lower concentrations proved to remain effective in bacteriophage elimination in association with porous materials. Stepwise reduction in gas concentration from 76 ppm to 5 ppm consistently resulted in greater than 99.99% to 100% reduction of recoverable bacteriophage. This model suggests the potential of ClO2 gas deployment systems for use in the inactivation of viral agents associated with porous potential fomites. The ClO2 gas could prove especially helpful in disinfecting enclosed areas containing viral contaminated surfaces, rather than manually spraying and wiping them.

Effects of the nozzle-to-nozzle distance on the performance of the water condensation growth-based virus aerosol concentrator

Inactivation of Salmonella enterica, Listeria monocytogenes and murine norovirus (MNV-1) on fresh strawberries by conventional and water-assisted ultraviolet light (UV-C)

Pure phenol is colorless and used in the manufacture of phenolic resins, plastics, explosives, fertilizers, paints, rubber, textiles, adhesives, pharmaceuticals, paper, soap, and wood preservatives. The purpose of this study was to compare the efficacy of several phenol decontamination strategies following dermal exposure using the pig as a model for human exposure, and then assess the effect of the two best treatments on phenol absorption in the isolated perfused porcine skin flap (IPPSF). Six anesthetized Yorkshire pigs were exposed to 89% aqueous phenol for 1 min using Hilltop chambers (10 skin sites/pig; 400 microl/site). Exposure to phenol was followed by one of 10 different decontamination procedures: 1-, 5-, 15-, and 30-min water wash; Ivory soap solution; polyethylene glycol (PEG 400); PEG 400/industrial methylated spirits (IMS); PEG 400/ethanol (EtOH); polyvinyl pyrrolidone (PVP)/70% isopropanol (IPA); and 70% IPA. For each of the last five strategies, 1-min treatment washes were repeatedly alternated with 1-min water washes for a total of 15 min. Evaluation was based on scoring of erythema, edema, and histological parameters such as intracellular and intercellular epidermal edema, papillary dermal edema, perivascular infiltrates, pyknotic stratum basale cells, and epidermal-dermal separation. It was concluded that PEG 400 and 70% IPA were superior to the other treatments investigated and equally efficacious in the reduction of phenol-induced skin damage. In addition, phenol absorption was assessed utilizing the two most effective in vivo treatments in the IPPSF. The assessment of percutaneous absorption of phenol found the PEG 400, 70% IPA, and 15-min water treatments significantly (P < 0.05) reduced phenol absorption relative to no treatment.

Viral diseases can spread through a variety of routes including aerosols. Yet, limited data are available on the efficacy of aerosolized chemicals to reduce viral loads in the air. Bacteriophages (phages) are often used as surrogates for hazardous viruses in aerosol studies because they are inexpensive, easy to handle, and safe for laboratory workers. Moreover, several of these bacterial viruses display physical characteristics similar to pathogenic human and animal viruses, like morphological size, type of nucleic acids, capsid morphology, and the presence of an envelope. In this study, the efficacy of four chemicals was evaluated on four airborne phages at two different relative humidity levels. Non-tailed bacteriophages MS2 (single-stranded RNA), ϕ6 (double-stranded RNA, enveloped), PR772 (double-stranded DNA), and ϕX174 (single-stranded DNA) were first aerosolized in a 55L rotative environmental chamber at 19°C with 25% and 50% relative humidity. Then, hydrogen peroxide, Eugenol (phenylpropene used in commercial perfumes and flavorings), Mist® (automobile disinfectant containing Triethylene glycol), and Pledge® (multisurface disinfectant containing Isopropanol, n-Alkyl Dimethyl Benzyl Amonium Chlorides, and n-Alkyl Dimethyl Ethylbenzyl Ammonium Chloride) were nebulized with the phages using a separate nebulizer. Aerosols were maintained in suspension during 10 minutes, 1 hour, and 2 hours. Viral aerosols were sampled using an SKC BioSampler and samples were analyzed using qPCR and plaque assays. The resistance levels of the four phages varied depending on the relative humidity (RH) and germicidal products tested. Phage MS2 was the most stable airborne virus under the environmental conditions tested while phage PR772 was the least stable. Pledge® and Eugenol reduced the infectivity of all airborne phages tested. At 25% RH, Pledge® and Eugenol were more effective at reducing infectivity of RNA phages ϕ6 and MS2. At 50% RH, Pledge® was the most effective agent against phage MS2. These findings illustrate that various airborne viruses should be tested to demonstrate the effectiveness of germicidal treatments. This research also provides a set of parameters for testing germicidal products in large-scale settings to reduce the risk of virus transmission.