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Richter WR, Weston BL, Sunderman MM, Willenberg Z, Ratliff K, Wood JP. Neutralization of ricin toxin on building interior surfaces using liquid decontaminants. PLoS One 2024; 19:e0302967. [PMID: 38722908 PMCID: PMC11081333 DOI: 10.1371/journal.pone.0302967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 04/16/2024] [Indexed: 05/13/2024] Open
Abstract
Ricin is a highly toxic protein, capable of inhibiting protein synthesis within cells, and is produced from the beans of the Ricinus communis (castor bean) plant. Numerous recent incidents involving ricin have occurred, many in the form of mailed letters resulting in both building and mail sorting facility contamination. The goal of this study was to assess the decontamination efficacy of several commercial off-the-shelf (COTS) cleaners and decontaminants (solutions of sodium hypochlorite [bleach], quaternary ammonium, sodium percarbonate, peracetic acid, and hydrogen peroxide) against a crude preparation of ricin toxin. The ricin was inoculated onto four common building materials (pine wood, drywall joint tape, countertop laminate, and industrial carpet), and the decontaminants were applied to the test coupons using a handheld sprayer. Decontamination efficacy was quantified using an in-vitro cytotoxicity assay to measure the quantity of bioactive ricin toxin extracted from test coupons as compared to the corresponding positive controls (not sprayed with decontaminant). Results showed that decontamination efficacy varied by decontaminant and substrate material, and that efficacy generally improved as the number of spray applications or contact time increased. The solutions of 0.45% peracetic acid and the 20,000-parts per million (ppm) sodium hypochlorite provided the overall best decontamination efficacy. The 0.45% peracetic acid solution achieved 97.8 to 99.8% reduction with a 30-min contact time.
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Affiliation(s)
| | - Bailey L. Weston
- Battelle Memorial Institute, Columbus, OH, United States of America
| | | | - Zach Willenberg
- Battelle Memorial Institute, Columbus, OH, United States of America
| | - Katherine Ratliff
- U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC, United States of America
| | - Joseph P. Wood
- U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC, United States of America
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Richter WR, Sunderman MM, Fulton M, Catyb J, Lewis D. Evaluation of altered environmental conditions as a decontamination approach for SARS-CoV-2 when applied to aircraft related materials. J Appl Microbiol 2023; 134:7075879. [PMID: 36898667 DOI: 10.1093/jambio/lxad051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/28/2023] [Accepted: 03/09/2023] [Indexed: 03/12/2023]
Abstract
AIMS The purpose of this study was to evaluate the effects of altered environmental conditions, specifically elevated temperature at various levels of expected relative humidity (RH), on the inactivation of SARS-CoV-2 when applied to U.S. Air Force aircraft materials. METHODS AND RESULTS SARS CoV-2 (USA-WA1/2020) was spiked (approximately 1×105 TCID50) in either synthetic saliva or lung fluid, dried onto porous (e.g., Nylon strap) and nonporous materials (e.g., bare aluminum, silicone, and ABS plastic), placed in a test chamber and exposed to environmental conditions ranging from 40-51.7°C and RH ranging from 0-50%. The amount of infectious SARS-CoV-2 was then assessed at various timepoints from 0-2 days. Warmer test temperatures, higher RH, and longer exposure duration resulted in higher inactivation rates per material type. Synthetic saliva inoculation vehicle was more readily decontaminated compared to materials inoculated with synthetic lung fluid. CONCLUSIONS SARS-CoV-2 was readily inactivated below limit of quantitation (LOQ) for all materials inoculated using synthetic saliva vehicle within 6 hours when exposed to environmental conditions of 51.7°C and RH ≥ 25%. Synthetic lung fluid vehicle did not follow the general trend of an increase in RH resulting in increased efficacy. The lung fluid performed best at the 20-25% RH range to achieve complete inactivation below LOQ.
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Affiliation(s)
| | | | - M Fulton
- Battelle Memorial Institute, Columbus, OH
| | - J Catyb
- Battelle Memorial Institute, Columbus, OH
| | - D Lewis
- Air Force Institute of Technology, Wright-Patterson Air Force Base, Dayton, OH
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Richter WR, Sunderman MM, Schaeufele DJ, Willenberg Z, Ratliff K, Calfee MW, Oudejans L. Evaluation of steam heat as a decontamination approach for SARS-CoV-2 when applied to common transit-related materials. J Appl Microbiol 2023; 134:lxad053. [PMID: 36906281 PMCID: PMC10257936 DOI: 10.1093/jambio/lxad053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/31/2023] [Accepted: 03/10/2023] [Indexed: 03/13/2023]
Abstract
AIMS The purpose of this study was to evaluate the efficacy of steam heat for inactivation of SARS-CoV-2 when applied to materials common in mass transit installations. METHODS AND RESULTS SARS CoV-2 (USA-WA1/2020) was resuspended in either cell culture media or synthetic saliva, inoculated (∼1 × 106 TCID50) onto porous and nonporous materials and subjected to steam inactivation efficacy tests as either wet or dried droplets. The inoculated test materials were exposed to steam heat ranging from 70°C to 90°C. The amount of infectious SARS-CoV-2 remaining after various exposure durations ranging from 1 to 60 s was assessed. Higher steam heat application resulted in higher inactivation rates at short contact times. Steam applied at 1-inch distance (∼90°C at the surface) resulted in complete inactivation for dry inoculum within 2 s of exposure (excluding two outliers of 19 test samples at the 5-s duration) and within 2-30 s of exposure for wet droplets. Increasing the distance to 2 inches (∼70°C) also increased the exposure time required to achieve complete inactivation to 15 or 30 s for materials inoculated with saliva or cell culture media, respectively. CONCLUSIONS Steam heat can provide high levels of decontamination (>3 log reduction) for transit-related materials contaminated with SARS-CoV-2 using a commercially available steam generator with a manageable exposure time of 2-5 s.
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Affiliation(s)
| | | | | | | | - Katherine Ratliff
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Solutions and Emergency Response, Research Triangle Park, NC 27711, United States
| | - M. Worth Calfee
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Solutions and Emergency Response, Research Triangle Park, NC 27711, United States
| | - Lukas Oudejans
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Solutions and Emergency Response, Research Triangle Park, NC 27711, United States
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Richter WR, Sunderman MM, Fulton ML, Willenberg Z, Serre S, Oudejans L, Wood J, Calfee MW. Decontamination efficacy of common liquid disinfectants against non-spore-forming biological agents in soil matrices. J Appl Microbiol 2022; 133:3659-3668. [PMID: 36056613 PMCID: PMC9748868 DOI: 10.1111/jam.15802] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/20/2022] [Accepted: 08/28/2022] [Indexed: 11/28/2022]
Abstract
AIMS The purpose of this study was to evaluate decontamination efficacy, within three soil types, against Yersinia pestis, Burkholderia pseudomallei, and the Venezuelan Equine Encephalitis virus (VEEV). METHODS AND RESULTS One of three liquid disinfectants (dilute bleach, Virkon-S or Klozur One) was added to three soil types (sand, loam, or clay) and allowed contact for four pre-spike durations: 0, 15, 30 and 60 min. Y. pestis, B. pseudomallei, or VEEV was then spiked into the soil (10 microliters or approx. 1 × 107 CFU or PFU into 1 g soil) and decontamination efficacy assessed at post-spike contact times of 10 or 60 min at ambient environmental conditions. Across all soil types, sandy soil resulted in the least quenching to all three disinfectants tested as shown by sustained decontamination efficacy across all pre-spike and post-spike timepoints. Clay and loam soil types exhibited quenching effects on the hypochlorite and peroxygen based disinfectants (dilute bleach and Virkon S) and in general resulted in decreased efficacy with increased pre-spike contact time. The sodium persulfate (Klozur One) performance was the most consistent across all soil types and pre-spike contact times, resulting in greater efficacy with increased post-spike time. CONCLUSIONS Liquid disinfectants can provide high levels of decontamination in soil for both viral and non-spore-forming bacterial select agents. Hypochlorite and peroxygen based disinfectants used in soils containing higher organic content (loam or clay) may require extended contact times or re-application of liquid disinfectant, in as little as 15 min of application, to achieve a 6-log reduction. SIGNIFICANCE AND IMPACT OF THE STUDY These results provide information for the performance of three disinfectants in soil against non-spore-forming select agents. These data may aid response decision makers following a biological contamination incident by informing the selection of disinfectant as well as the re-application time to achieve effective site remediation.
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Affiliation(s)
| | | | | | | | - Shannon Serre
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, North Carolina, USA
| | - Lukas Oudejans
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, North Carolina, USA
| | - Joseph Wood
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, North Carolina, USA
| | - Michael W. Calfee
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, North Carolina, USA
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Choi YW, Sunderman MM, McCauley MW, Richter WR, Willenberg ZJ, Wood J, Serre S, Mickelsen L, Willison S, Rupert R, Muñiz-Ortiz JG, Casey S, Calfee MW. Decontamination of Bacillus Spores with Formaldehyde Vapor under Varied Environmental Conditions. Appl Biosaf 2021; 26:139-53. [PMID: 32982605 PMCID: PMC7511015 DOI: 10.1089/apb.21.926975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Introduction This study investigated formaldehyde decontamination efficacy against dried Bacillus spores on porous and non-porous test surfaces, under various environmental conditions. This knowledge will help responders determine effective formaldehyde exposure parameters to decontaminate affected spaces following a biological agent release. Methods Prescribed masses of paraformaldehyde or formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor within a bench-scale test chamber. Adsorbent cartridges were used to measure formaldehyde vapor concentrations in the chamber at pre-determined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. Spores of Bacillus globigii, Bacillus thuringiensis, and Bacillus anthracis were inoculated and dried onto porous bare pine wood and non-porous painted concrete material coupons. A series of tests was conducted where temperature, relative humidity, and formaldehyde concentration were varied, to determine treatment efficacy outside of conditions where this decontaminant is well-characterized (laboratory temperature and humidity and 12 mg/L theoretical formaldehyde vapor concentration) to predict decontamination efficacy in applications that may arise following a biological incident. Results Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations collected in the ambient temperature trials (approximately 22°C). Generally, decontamination efficacy on wood was lower for all three spore types compared with painted concrete. Also, higher recoveries resulted from painted concrete compared to wood, consistent with historical data on these materials. The highest decontamination efficacies were observed on the spores subjected to the longest exposures (48 hours) on both materials, with efficacies that gradually decreased with shorter exposures. Adsorption or absorption of the formaldehyde vapor may have been a factor, especially during the low temperature trials, resulting in less available formaldehyde in the air when measured. Conclusion Environmental conditions affect formaldehyde concentrations in the air and thereby affect decontamination efficacy. Efficacy is also impacted by the material with which the contaminants are in contact.
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Affiliation(s)
| | | | | | | | | | - Joseph Wood
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, NC, USA
| | - Shannon Serre
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, NC, USA
| | - Leroy Mickelsen
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, NC, USA
| | | | - Rich Rupert
- US Environmental Protection Agency, Region 3, Philadelphia, PA
| | | | - Sara Casey
- United Kingdom, Department for Environment, Food and Rural Affairs, CBRN Recovery Team, Stafford, England
| | - M Worth Calfee
- US Environmental Protection Agency, TW Alexander Drive, Research Triangle Park, NC, USA
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Choi YW, Sunderman MM, McCauley MW, Richter WR, Willenberg ZJ, Wood J, Serre S, Mickelsen L, Willison S, Rupert R, Muñiz Ortiz JG, Casey S, Calfee MW. Formaldehyde Vapor Characteristics in Varied Decontamination Environments. Appl Biosaf 2021; 26:33-41. [PMID: 34017220 DOI: 10.1089/apb.21.926968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Introduction This effort investigated formaldehyde vapor characteristics under various environmental conditions by the analyses of air samples collected over a time-course. This knowledge will help responders achieve desired formaldehyde exposure parameters for decontamination of affected spaces after a biological contamination incident. Methods Prescribed masses of paraformaldehyde and formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor. Adsorbent cartridges were used to collect air samples from the test chamber at predetermined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. In addition, material demand for the formaldehyde was evaluated by inclusion of arrays of Plexiglas panels in the test chamber to determine the impact of varied surface areas within the test chamber. Temperature was controlled with a circulating water bath connected to a radiator and fan inside the chamber. Relative humidity was controlled with humidity fixed-point salt solutions and water vapor generated from evaporated water. Results Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations in the ambient temperature trials (approximately 22°C). The addition of clear Plexiglas panels to increase the surface area of the test chamber interior resulted in appreciable decreases of formaldehyde air concentration when compared to an empty test chamber. Conclusion This work has shown that environmental variables and surface-to-volume ratios in the decontaminated space may affect the availability of formaldehyde in the air and, therefore, may affect decontamination effectiveness.
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Affiliation(s)
| | | | | | | | | | - Joseph Wood
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Shannon Serre
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Leroy Mickelsen
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | | | - Rich Rupert
- US Environmental Protection Agency, Region 3, Philadelphia, PA, USA
| | | | - Sara Casey
- Department for Environment, Food and Rural Affairs, CBRN Recovery Team, Stafford, UK
| | - M Worth Calfee
- US Environmental Protection Agency, Research Triangle Park, NC, USA
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Choi YW, Sunderman MM, McCauley MW, Richter WR, Willenberg ZJ, Wood J, Serre S, Mickelsen L, Willison S, Rupert R, Ortiz JGM, Casey S, Calfee MW. Decontamination of Bacillus Spores with Formaldehyde Vapor Under Varied Environmental Conditions. Appl Biosaf 2020. [DOI: 10.1177/1535676020926975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Introduction: This effort investigated formaldehyde vapor characteristics under various environmental conditions by the analyses of air samples collected over a time-course. This knowledge will help responders achieve desired formaldehyde exposure parameters for decontamination of affected spaces after a biological contamination incident. Methods: Prescribed masses of paraformaldehyde and formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor. Adsorbent cartridges were used to collect air samples from the test chamber at predetermined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. In addition, material demand for the formaldehyde was evaluated by inclusion of arrays of Plexiglas panels in the test chamber to determine the effect of varied surface areas within the test chamber. Temperature was controlled with a circulating water bath connected to a radiator and fan inside the chamber. Relative humidity was controlled with humidity fixed-point salt solutions and water vapor generated from evaporated water. Results: Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations in the ambient temperature trials (approximately 22°C). The addition of clear Plexiglas panels to increase the surface area of the test chamber interior resulted in appreciable decreases of formaldehyde air concentration when compared to an empty test chamber. Conclusion: This work has shown that environmental variables and surface-to-volume ratios in the decontaminated space may affect the availability of formaldehyde in the air and, therefore, may affect decontamination effectiveness.
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Affiliation(s)
| | | | | | | | | | - Joseph Wood
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Shannon Serre
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Leroy Mickelsen
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | | | - Rich Rupert
- US Environmental Protection Agency, Region 3, Philadelphia, PA, USA
| | | | - Sara Casey
- Department for Environment, Food and Rural Affairs, CBRN Recovery Team, Stafford, UK
| | - M. Worth Calfee
- US Environmental Protection Agency, Research Triangle Park, NC, USA
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Choi YW, Sunderman MM, McCauley MW, Richter WR, Willenberg ZJ, Wood J, Serre S, Mickelsen L, Willison S, Rupert R, Ortiz JGM, Casey S, Calfee MW. Formaldehyde Vapor Characteristics in Varied Decontamination Environments. Appl Biosaf 2020. [DOI: 10.1177/1535676020926968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction: This effort investigated formaldehyde vapor characteristics under various environmental conditions by the analyses of air samples collected over a time-course. This knowledge will help responders achieve desired formaldehyde exposure parameters for decontamination of affected spaces after a biological contamination incident. Methods: Prescribed masses of paraformaldehyde and formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor. Adsorbent cartridges were used to collect air samples from the test chamber at predetermined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. In addition, material demand for the formaldehyde was evaluated by inclusion of arrays of Plexiglas panels in the test chamber to determine the impact of varied surface areas within the test chamber. Temperature was controlled with a circulating water bath connected to a radiator and fan inside the chamber. Relative humidity was controlled with humidity fixed-point salt solutions and water vapor generated from evaporated water. Results: Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations in the ambient temperature trials (approximately 22°C). The addition of clear Plexiglas panels to increase the surface area of the test chamber interior resulted in appreciable decreases of formaldehyde air concentration when compared to an empty test chamber. Conclusion: This work has shown that environmental variables and surface-to-volume ratios in the decontaminated space may affect the availability of formaldehyde in the air and, therefore, may affect decontamination effectiveness.
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Affiliation(s)
| | | | | | | | | | - Joseph Wood
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Shannon Serre
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Leroy Mickelsen
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | | | - Rich Rupert
- US Environmental Protection Agency, Region 3, Philadelphia, PA, USA
| | | | - Sara Casey
- Department for Environment, Food and Rural Affairs, CBRN Recovery Team, Stafford, UK
| | - M. Worth Calfee
- US Environmental Protection Agency, Research Triangle Park, NC, USA
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Richter WR, Sunderman MM, Wendling MQS, Serre S, Mickelsen L, Rupert R, Wood J, Choi Y, Willenberg Z, Calfee MW. Evaluation of altered environmental conditions as a decontamination approach for nonspore-forming biological agents. J Appl Microbiol 2020; 128:1050-1059. [PMID: 31782200 PMCID: PMC7323857 DOI: 10.1111/jam.14532] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/11/2019] [Accepted: 11/21/2019] [Indexed: 01/04/2023]
Abstract
AIMS The purpose of this study was to evaluate the effects of altered environmental conditions on the persistence of Francisella tularensis bacteria and Venezuelan equine encephalitis virus (VEEV), on two material types. METHODS AND RESULTS Francisella tularensis (F.t.) and VEEV were inoculated (c. 1 × 108 colony-forming units or PFU), dried onto porous and nonporous fomites (glass and paper), and exposed to combinations of altered environmental conditions ranging from 22 to 60°C and 30 to 75% relative humidity (RH). Viability of test organism was assessed after contact times ranging from 30 min to 10 days. Inactivation rates of F.t. and VEEV increased as both temperature and/or RH were increased. Greater efficacy was observed for paper as compared to glass for both test organisms. CONCLUSIONS The use of elevated temperature and RH increased rate of inactivation for both organisms and greater than six log reduction was accomplished in as little as 6 h by elevating temperature to approximately 60°C. SIGNIFICANCE AND IMPACT OF THE STUDY These results provide information for inactivation of nonspore-forming select agents using elevated temperature and humidity which may aid incident commanders following a biological contamination incident by providing alternative methods for remediation.
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Affiliation(s)
- W R Richter
- Battelle Memorial Institute, Columbus, OH, USA
| | | | | | - S Serre
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - L Mickelsen
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - R Rupert
- US Environmental Protection Agency, Philadelphia, PA, USA
| | - J Wood
- US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Y Choi
- Battelle Memorial Institute, Columbus, OH, USA
| | | | - M W Calfee
- US Environmental Protection Agency, Research Triangle Park, NC, USA
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