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Derk RC, Coyle JP, Lindsley WG, Blachere FM, Lemons AR, Service SK, Martin SB, Mead KR, Fotta SA, Reynolds JS, McKinney WG, Sinsel EW, Beezhold DH, Noti JD. Efficacy of Do-It-Yourself air filtration units in reducing exposure to simulated respiratory aerosols. Build Environ 2023; 229:109920. [PMID: 36569517 PMCID: PMC9759459 DOI: 10.1016/j.buildenv.2022.109920] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/03/2022] [Accepted: 12/12/2022] [Indexed: 05/20/2023]
Abstract
Many respiratory diseases, including COVID-19, can be spread by aerosols expelled by infected people when they cough, talk, sing, or exhale. Exposure to these aerosols indoors can be reduced by portable air filtration units (air cleaners). Homemade or Do-It-Yourself (DIY) air filtration units are a popular alternative to commercially produced devices, but performance data is limited. Our study used a speaker-audience model to examine the efficacy of two popular types of DIY air filtration units, the Corsi-Rosenthal cube and a modified Ford air filtration unit, in reducing exposure to simulated respiratory aerosols within a mock classroom. Experiments were conducted using four breathing simulators at different locations in the room, one acting as the respiratory aerosol source and three as recipients. Optical particle spectrometers monitored simulated respiratory aerosol particles (0.3-3 μm) as they dispersed throughout the room. Using two DIY cubes (in the front and back of the room) increased the air change rate as much as 12.4 over room ventilation, depending on filter thickness and fan airflow. Using multiple linear regression, each unit increase of air change reduced exposure by 10%. Increasing the number of filters, filter thickness, and fan airflow significantly enhanced the air change rate, which resulted in exposure reductions of up to 73%. Our results show DIY air filtration units can be an effective means of reducing aerosol exposure. However, they also show performance of DIY units can vary considerably depending upon their design, construction, and positioning, and users should be mindful of these limitations.
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Affiliation(s)
- Raymond C Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Jayme P Coyle
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Angela R Lemons
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Samantha K Service
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Stephen B Martin
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26505, USA
| | - Kenneth R Mead
- Division of Field Studies and Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH, 45226, USA
| | - Steven A Fotta
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Jeffrey S Reynolds
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Walter G McKinney
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Erik W Sinsel
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - Donald H Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1000 Fredrick Lane, Morgantown, WV, 26508, USA
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Lindsley WG, Blachere FM, Derk RC, Boots T, Duling MG, Boutin B, Beezhold DH, Noti JD. Constant vs. cyclic flow when testing face masks and respirators as source control devices for simulated respiratory aerosols. Aerosol Sci Technol 2023; 57:215-232. [PMID: 37206373 PMCID: PMC10194085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
SARS-CoV-2 spreads by infectious aerosols and droplets from the respiratory tract. Masks and respirators can reduce the transmission of infectious respiratory diseases by collecting these aerosols at the source. The ability of source control devices to block aerosols can be tested by expelling an aerosol through a headform using constant airflows, which are simpler, or cyclic airflows, which are more realistic but require more complex methods. Experiments with respirators found that using cyclic vs. constant flows affected the amount of aerosol inhaled, but similar comparisons have not been made for source control devices with exhaled aerosols. We measured the collection efficiencies for exhaled aerosols for two cloth masks, two medical masks with and without an elastic mask brace, a neck gaiter, and an N95 filtering facepiece respirator using 15 L/min and 85 L/min constant and cyclic flows and a headform with pliable skin. The collection efficiencies for the 15 L/min cyclic flow, 15 L/min constant flow, and 85 L/min constant flow were not significantly different in most cases. The apparent collection efficiencies for the 85 L/min cyclic flow were artificially increased by rebreathing and refiltration of the aerosol from the collection chamber. The collection efficiencies correlated well with the fit factors (ρ > 0.95) but not the filtration efficiencies (ρ < 0.54). Our results suggest that the aerosol collection efficiency measurements of source control devices are comparable when testing the devices using either constant or cyclic airflows and that the potential for aerosol rebreathing must be considered when conducting experiments.
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Affiliation(s)
- William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Raymond C. Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Theresa Boots
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Matthew G. Duling
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brenda Boutin
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Donald H. Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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Coyle JP, Derk RC, Lindsley WG, Boots T, Blachere FM, Reynolds JS, McKinney WG, Sinsel EW, Lemons AR, Beezhold DH, Noti JD. Reduction of exposure to simulated respiratory aerosols using ventilation, physical distancing, and universal masking. Indoor Air 2022; 32:e12987. [PMID: 35225389 PMCID: PMC8988470 DOI: 10.1111/ina.12987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/23/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
To limit community spread of SARS-CoV-2, CDC recommends universal masking indoors, maintaining 1.8 m of physical distancing, adequate ventilation, and avoiding crowded indoor spaces. Several studies have examined the independent influence of each control strategy in mitigating transmission in isolation, yet controls are often implemented concomitantly within an indoor environment. To address the influence of physical distancing, universal masking, and ventilation on very fine respiratory droplets and aerosol particle exposure, a simulator that coughed and exhaled aerosols (the source) and a second breathing simulator (the recipient) were placed in an exposure chamber. When controlling for the other two mitigation strategies, universal masking with 3-ply cotton masks reduced exposure to 0.3-3 µm coughed and exhaled aerosol particles by >77% compared to unmasked tests, whereas physical distancing (0.9 or 1.8 m) significantly changed exposure to cough but not exhaled aerosols. The effectiveness of ventilation depended upon the respiratory activity, that is, coughing or breathing, as well as the duration of exposure time. Our results demonstrate that a layered mitigation strategy approach of administrative and engineering controls can reduce personal inhalation exposure to potentially infectious very fine respiratory droplets and aerosol particles within an indoor environment.
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Affiliation(s)
- Jayme P. Coyle
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Raymond C. Derk
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - William G. Lindsley
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Theresa Boots
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Francoise M. Blachere
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Jeffrey S. Reynolds
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Walter G. McKinney
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Erik W. Sinsel
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Angela R. Lemons
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Donald H. Beezhold
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - John D. Noti
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
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Blachere FM, Lemons AR, Coyle JP, Derk RC, Lindsley WG, Beezhold DH, Woodfork K, Duling MG, Boutin B, Boots T, Harris JR, Nurkiewicz T, Noti JD. Face mask fit modifications that improve source control performance. Am J Infect Control 2022; 50:133-140. [PMID: 34924208 PMCID: PMC8674119 DOI: 10.1016/j.ajic.2021.10.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND During the COVID-19 pandemic, face masks are used as source control devices to reduce the expulsion of respiratory aerosols from infected people. Modifications such as mask braces, earloop straps, knotting and tucking, and double masking have been proposed to improve mask fit however the data on source control are limited. METHODS The effectiveness of mask fit modifications was determined by conducting fit tests on human subjects and simulator manikins and by performing simulated coughs and exhalations using a source control measurement system. RESULTS Medical masks without modification blocked ≥56% of cough aerosols and ≥42% of exhaled aerosols. Modifying fit by crossing the earloops or placing a bracket under the mask did not increase performance, while using earloop toggles, an earloop strap, and knotting and tucking the mask increased performance. The most effective modifications for improving source control performance were double masking and using a mask brace. Placing a cloth mask over a medical mask blocked ≥85% of cough aerosols and ≥91% of exhaled aerosols. Placing a brace over a medical mask blocked ≥95% of cough aerosols and ≥99% of exhaled aerosols. CONCLUSIONS Fit modifications can greatly improve the performance of face masks as source control devices for respiratory aerosols.
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Affiliation(s)
- Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV.
| | - Angela R Lemons
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - Jayme P Coyle
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - Raymond C Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - Donald H Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - Karen Woodfork
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, WV; Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, WV
| | - Matthew G Duling
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - Brenda Boutin
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - Theresa Boots
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - James R Harris
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
| | - Tim Nurkiewicz
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, WV; Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, WV
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV
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Coyle JP, Derk RC, Lindsley WG, Blachere FM, Boots T, Lemons AR, Martin SB, Mead KR, Fotta SA, Reynolds JS, McKinney WG, Sinsel EW, Beezhold DH, Noti JD. Efficacy of Ventilation, HEPA Air Cleaners, Universal Masking, and Physical Distancing for Reducing Exposure to Simulated Exhaled Aerosols in a Meeting Room. Viruses 2021; 13:2536. [PMID: 34960804 PMCID: PMC8707272 DOI: 10.3390/v13122536] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/07/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022] Open
Abstract
There is strong evidence associating the indoor environment with transmission of SARS-CoV-2, the virus that causes COVID-19. SARS-CoV-2 can spread by exposure to droplets and very fine aerosol particles from respiratory fluids that are released by infected persons. Layered mitigation strategies, including but not limited to maintaining physical distancing, adequate ventilation, universal masking, avoiding overcrowding, and vaccination, have shown to be effective in reducing the spread of SARS-CoV-2 within the indoor environment. Here, we examine the effect of mitigation strategies on reducing the risk of exposure to simulated respiratory aerosol particles within a classroom-style meeting room. To quantify exposure of uninfected individuals (Recipients), surrogate respiratory aerosol particles were generated by a breathing simulator with a headform (Source) that mimicked breath exhalations. Recipients, represented by three breathing simulators with manikin headforms, were placed in a meeting room and affixed with optical particle counters to measure 0.3-3 µm aerosol particles. Universal masking of all breathing simulators with a 3-ply cotton mask reduced aerosol exposure by 50% or more compared to scenarios with simulators unmasked. While evaluating the effect of Source placement, Recipients had the highest exposure at 0.9 m in a face-to-face orientation. Ventilation reduced exposure by approximately 5% per unit increase in air change per hour (ACH), irrespective of whether increases in ACH were by the HVAC system or portable HEPA air cleaners. The results demonstrate that mitigation strategies, such as universal masking and increasing ventilation, reduce personal exposure to respiratory aerosols within a meeting room. While universal masking remains a key component of a layered mitigation strategy of exposure reduction, increasing ventilation via system HVAC or portable HEPA air cleaners further reduces exposure.
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Affiliation(s)
- Jayme P. Coyle
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Raymond C. Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Theresa Boots
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Angela R. Lemons
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Stephen B. Martin
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA;
| | - Kenneth R. Mead
- Division of Field Studies and Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH 45226, USA;
| | - Steven A. Fotta
- Facilities Management Office, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA;
| | - Jeffrey S. Reynolds
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Walter G. McKinney
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Erik W. Sinsel
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - Donald H. Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA; (J.P.C.); (R.C.D.); (F.M.B.); (T.B.); (A.R.L.); (J.S.R.); (W.G.M.); (E.W.S.); (D.H.B.); (J.D.N.)
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Lindsley WG, Beezhold DH, Coyle J, Derk RC, Blachere FM, Boots T, Reynolds JS, McKinney WG, Sinsel E, Noti JD. Efficacy of universal masking for source control and personal protection from simulated cough and exhaled aerosols in a room. J Occup Environ Hyg 2021; 18:409-422. [PMID: 34161193 PMCID: PMC8355198 DOI: 10.1080/15459624.2021.1939879] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Face masks reduce the expulsion of respiratory aerosols produced during coughs and exhalations ("source control"). Factors such as the directions in which people are facing (orientation) and separation distance also affect aerosol dispersion. However, it is not clear how the combined effects of masking, orientation, and distance affect the exposure of individuals to respiratory aerosols in indoor spaces. We placed a respiratory aerosol simulator ("source") and a breathing simulator ("recipient") in a 3 m × 3 m chamber and measured aerosol concentrations for different combinations of masking, orientation, and separation distance. When the simulators were front-to-front during coughing, masks reduced the 15-min mean aerosol concentration at the recipient by 92% at 0.9 and 1.8 m separation. When the simulators were side-by-side, masks reduced the concentration by 81% at 0.9 m and 78% at 1.8 m. During breathing, masks reduced the aerosol concentration by 66% when front-to-front and 76% when side-by-side at 0.9 m. Similar results were seen at 1.8 m. When the simulators were unmasked, changing the orientations from front-to-front to side-by-side reduced the cough aerosol concentration by 59% at 0.9 m and 60% at 1.8 m. When both simulators were masked, changing the orientations did not significantly change the concentration at either distance during coughing or breathing. Increasing the distance between the simulators from 0.9 m to 1.8 m during coughing reduced the aerosol concentration by 25% when no masks were worn but had little effect when both simulators were masked. During breathing, when neither simulator was masked, increasing the separation reduced the concentration by 13%, which approached significance, while the change was not significant when both source and recipient were masked. Our results show that universal masking reduces exposure to respiratory aerosol particles regardless of the orientation and separation distance between the source and recipient.
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Affiliation(s)
- William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Donald H Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Jayme Coyle
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Raymond C Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Theresa Boots
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Jeffrey S Reynolds
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Walter G McKinney
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Erik Sinsel
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
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Lindsley WG, Derk RC, Coyle JP, Martin SB, Mead KR, Blachere FM, Beezhold DH, Brooks JT, Boots T, Noti JD. Efficacy of Portable Air Cleaners and Masking for Reducing Indoor Exposure to Simulated Exhaled SARS-CoV-2 Aerosols - United States, 2021. MMWR Morb Mortal Wkly Rep 2021; 70:972-976. [PMID: 34237047 PMCID: PMC8312755 DOI: 10.15585/mmwr.mm7027e1] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Lindsley WG, Blachere FM, Beezhold DH, Law BF, Derk RC, Hettick JM, Woodfork K, Goldsmith WT, Harris JR, Duling MG, Boutin B, Nurkiewicz T, Boots T, Coyle J, Noti JD. A comparison of performance metrics for cloth masks as source control devices for simulated cough and exhalation aerosols. Aerosol Sci Technol 2021; 55:1125-1142. [PMID: 35923216 PMCID: PMC9345405 DOI: 10.1080/02786826.2021.1933377] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Universal mask wearing is recommended to help control the spread of COVID-19. Masks reduce the expulsion of aerosols of respiratory fluids into the environment (called source control) and offer some protection to the wearer. Masks are often characterized using filtration efficiency, airflow resistance, and manikin or human fit factors, which are standard metrics used for personal protective devices. However, none of these metrics are direct measurements of how effectively a mask blocks coughed and exhaled aerosols. We studied the source control performance of 15 cloth masks (face masks, neck gaiters, and bandanas), two medical masks, and two N95 filtering facepiece respirators by measuring their ability to block aerosols ≤ 7 μm expelled during simulated coughing and exhalation (called source control collection efficiency). These measurements were compared with filtration efficiencies, airflow resistances, and fit factors measured on manikin headforms and humans. Collection efficiencies for the cloth masks ranged from 17% to 71% for coughing and 35% to 66% for exhalation. Filtration efficiencies for the cloth masks ranged from 1.4% to 98%, while the fit factors were 1.3 to 7.4 on headforms and 1.0 to 4.0 on human subjects. The Spearman's rank correlation coefficients between the source control collection efficiencies and the standard metrics ranged from 0.03 to 0.68 and were significant in all but two cases. However, none of the standard metrics were strongly correlated with source control performance. A better understanding of the relationships between source control collection efficiency, filtration efficiency, airflow resistance, and fit factor is needed.
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Affiliation(s)
- William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Donald H. Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brandon F. Law
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Raymond C. Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Justin M. Hettick
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Karen Woodfork
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - William T. Goldsmith
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - James R. Harris
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Matthew G. Duling
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brenda Boutin
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Timothy Nurkiewicz
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Theresa Boots
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Jayme Coyle
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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Brooks JT, Beezhold DH, Noti JD, Coyle JP, Derk RC, Blachere FM, Lindsley WG. Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021. MMWR Morb Mortal Wkly Rep 2021; 70:254-257. [PMID: 33600386 PMCID: PMC7891692 DOI: 10.15585/mmwr.mm7007e1] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Universal masking is one of the prevention strategies recommended by CDC to slow the spread of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19) (1). As of February 1, 2021, 38 states and the District of Columbia had universal masking mandates. Mask wearing has also been mandated by executive order for federal property* as well as on domestic and international transportation conveyances.† Masks substantially reduce exhaled respiratory droplets and aerosols from infected wearers and reduce exposure of uninfected wearers to these particles. Cloth masks§ and medical procedure masks¶ fit more loosely than do respirators (e.g., N95 facepieces). The effectiveness of cloth and medical procedure masks can be improved by ensuring that they are well fitted to the contours of the face to prevent leakage of air around the masks' edges. During January 2021, CDC conducted experimental simulations using pliable elastomeric source and receiver headforms to assess the extent to which two modifications to medical procedure masks, 1) wearing a cloth mask over a medical procedure mask (double masking) and 2) knotting the ear loops of a medical procedure mask where they attach to the mask's edges and then tucking in and flattening the extra material close to the face (knotted and tucked masks), could improve the fit of these masks and reduce the receiver's exposure to an aerosol of simulated respiratory droplet particles of the size considered most important for transmitting SARS-CoV-2. The receiver's exposure was maximally reduced (>95%) when the source and receiver were fitted with modified medical procedure masks. These laboratory-based experiments highlight the importance of good fit to optimize mask performance. Until vaccine-induced population immunity is achieved, universal masking is a highly effective means to slow the spread of SARS-CoV-2** when combined with other protective measures, such as physical distancing, avoiding crowds and poorly ventilated indoor spaces, and good hand hygiene. Innovative efforts to improve the fit of cloth and medical procedure masks to enhance their performance merit attention.
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10
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Lindsley WG, Blachere FM, Beezhold DH, Law BF, Derk RC, Hettick JM, Woodfork K, Goldsmith WT, Harris JR, Duling MG, Boutin B, Nurkiewicz T, Noti JD. A comparison of performance metrics for cloth face masks as source control devices for simulated cough and exhalation aerosols. medRxiv 2021:2021.02.16.21251850. [PMID: 33619500 PMCID: PMC7899465 DOI: 10.1101/2021.02.16.21251850] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Universal mask wearing is recommended by the Centers for Disease Control and Prevention to help control the spread of COVID-19. Masks reduce the expulsion of respiratory aerosols (called source control) and offer some protection to the wearer. However, masks vary greatly in their designs and construction materials, and it is not clear which are most effective. Our study tested 15 reusable cloth masks (which included face masks, neck gaiters, and bandanas), two medical masks, and two N95 filtering facepiece respirators as source control devices for aerosols ≤ 7 µm produced during simulated coughing and exhalation. These measurements were compared with the mask filtration efficiencies, airflow resistances, and fit factors. The source control collection efficiencies for the cloth masks ranged from 17% to 71% for coughing and 35% to 66% for exhalation. The filtration efficiencies of the cloth masks ranged from 1.4% to 98%, while the fit factors were 1.3 to 7.4 on an elastomeric manikin headform and 1.0 to 4.0 on human test subjects. The correlation coefficients between the source control efficacies and the other performance metrics ranged from 0.31 to 0.66 and were significant in all but one case. However, none of the alternative metrics were strong predictors of the source control performance of cloth masks. Our results suggest that a better understanding of the relationships between source control performance and metrics like filtration efficiency, airflow resistance, and fit factor are needed to develop simple methods to estimate the effectiveness of masks as source control devices for respiratory aerosols.
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Affiliation(s)
- William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Donald H. Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brandon F. Law
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Raymond C. Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Justin M. Hettick
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Karen Woodfork
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - William T. Goldsmith
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - James R. Harris
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Matthew G. Duling
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brenda Boutin
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Timothy Nurkiewicz
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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11
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Lindsley WG, Blachere FM, Law BF, Beezhold DH, Noti JD. Efficacy of face masks, neck gaiters and face shields for reducing the expulsion of simulated cough-generated aerosols. Aerosol Sci Technol 2021; 55:449-457. [PMID: 35924077 PMCID: PMC9345365 DOI: 10.1080/02786826.2020.1862409] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 05/18/2023]
Abstract
Face masks are recommended to reduce community transmission of SARS-CoV-2. One of the primary benefits of face masks and other coverings is as source control devices to reduce the expulsion of respiratory aerosols during coughing, breathing, and speaking. Face shields and neck gaiters have been proposed as an alternative to face masks, but information about face shields and neck gaiters as source control devices is limited. We used a cough aerosol simulator with a pliable skin headform to propel small aerosol particles (0 to 7 μm) into different face coverings. An N95 respirator blocked 99% (standard deviation (SD) 0.3%) of the cough aerosol, a medical grade procedure mask blocked 59% (SD 6.9%), a 3-ply cotton cloth face mask blocked 51% (SD 7.7%), and a polyester neck gaiter blocked 47% (SD 7.5%) as a single layer and 60% (SD 7.2%) when folded into a double layer. In contrast, the face shield blocked 2% (SD 15.3%) of the cough aerosol. Our results suggest that face masks and neck gaiters are preferable to face shields as source control devices for cough aerosols.
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Affiliation(s)
- William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brandon F. Law
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Donald H. Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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12
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Lindsley WG, Blachere FM, Law BF, Beezhold DH, Noti JD. Efficacy of face masks, neck gaiters and face shields for reducing the expulsion of simulated cough-generated aerosols. Aerosol Sci Technol 2021; 55:449-457. [PMID: 35924077 DOI: 10.1101/2020.10.05.20207241] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Face masks are recommended to reduce community transmission of SARS-CoV-2. One of the primary benefits of face masks and other coverings is as source control devices to reduce the expulsion of respiratory aerosols during coughing, breathing, and speaking. Face shields and neck gaiters have been proposed as an alternative to face masks, but information about face shields and neck gaiters as source control devices is limited. We used a cough aerosol simulator with a pliable skin headform to propel small aerosol particles (0 to 7 μm) into different face coverings. An N95 respirator blocked 99% (standard deviation (SD) 0.3%) of the cough aerosol, a medical grade procedure mask blocked 59% (SD 6.9%), a 3-ply cotton cloth face mask blocked 51% (SD 7.7%), and a polyester neck gaiter blocked 47% (SD 7.5%) as a single layer and 60% (SD 7.2%) when folded into a double layer. In contrast, the face shield blocked 2% (SD 15.3%) of the cough aerosol. Our results suggest that face masks and neck gaiters are preferable to face shields as source control devices for cough aerosols.
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Affiliation(s)
- William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brandon F Law
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Donald H Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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13
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Lindsley WG, Blachere FM, Burton NC, Christensen B, Estill CF, Fisher EM, Martin SB, Mead KR, Noti JD, Seaton M. COVID-19 and the Workplace: Research Questions for the Aerosol Science Community. Aerosol Sci Technol 2020; 54:1117-1123. [PMID: 35924028 PMCID: PMC9345404 DOI: 10.1080/02786826.2020.1796921] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/14/2020] [Indexed: 06/13/2023]
Affiliation(s)
- William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Nancy C. Burton
- Division of Field Studies & Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
| | | | - Cherie F. Estill
- Division of Field Studies & Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
| | - Edward M. Fisher
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Pittsburgh, Pennsylvania, USA
| | - Stephen B. Martin
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Kenneth R. Mead
- Division of Field Studies & Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Melissa Seaton
- Division of Science Integration, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
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14
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Lindsley WG, Blachere FM, McClelland TL, Neu DT, Mnatsakanova A, Martin SB, Mead KR, Noti JD. Efficacy of an ambulance ventilation system in reducing EMS worker exposure to airborne particles from a patient cough aerosol simulator. J Occup Environ Hyg 2019; 16:804-816. [PMID: 31638865 DOI: 10.1080/15459624.2019.1674858] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The protection of emergency medical service (EMS) workers from airborne disease transmission is important during routine transport of patients with infectious respiratory illnesses and would be critical during a pandemic of a disease such as influenza. However, few studies have examined the effectiveness of ambulance ventilation systems at reducing EMS worker exposure to airborne particles (aerosols). In our study, a cough aerosol simulator mimicking a coughing patient with an infectious respiratory illness was placed on a patient cot in an ambulance. The concentration and dispersion of cough aerosol particles were measured for 15 min at locations corresponding to likely positions of an EMS worker treating the patient. Experiments were performed with the patient cot at an angle of 0° (horizontal), 30°, and 60°, and with the ambulance ventilation system set to 0, 5, and 12 air changes/hour (ACH). Our results showed that increasing the air change rate significantly reduced the airborne particle concentration (p < 0.001). Increasing the air change rate from 0 to 5 ACH reduced the mean aerosol concentration by 34% (SD = 19%) overall, while increasing it from 0 to 12 ACH reduced the concentration by 68% (SD = 9%). Changing the cot angle also affected the concentration (p < 0.001), but the effect was more modest, especially at 5 and 12 ACH. Contrary to our expectations, the aerosol concentrations at the different worker positions were not significantly different (p < 0.556). Flow visualization experiments showed that the ventilation system created a recirculation pattern which helped disperse the aerosol particles throughout the compartment, reducing the effectiveness of the system. Our findings indicate that the ambulance ventilation system reduced but did not eliminate worker exposure to infectious aerosol particles. Aerosol exposures were not significantly different at different locations within the compartment, including locations behind and beside the patient. Improved ventilation system designs with smoother and more unidirectional airflows could provide better worker protection.
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Affiliation(s)
- William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Tia L McClelland
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Dylan T Neu
- Division of Field Studies & Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
| | - Anna Mnatsakanova
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Stephen B Martin
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Kenneth R Mead
- Division of Field Studies & Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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15
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Farcas D, Blachere FM, Kashon ML, Sbarra D, Schwegler-Berry D, Stull JO, Noti JD. Survival of Staphylococcus aureus on the outer shell of fire fighter turnout gear after sanitation in a commercial washer/extractor. J Occup Med Toxicol 2019; 14:10. [PMID: 30949228 PMCID: PMC6431055 DOI: 10.1186/s12995-019-0230-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/14/2019] [Indexed: 11/24/2022] Open
Abstract
Background Methicillin-resistant Staphylococcus aureus contamination on surfaces including turnout gear had been found throughout a number of fire stations. As such, the outer shell barrier of turnout gear jackets may be an indirect transmission source and proper disinfection is essential to reduce the risk of exposure to fire fighters. Cleaning practices vary considerably among fire stations, and a method to assess disinfection of gear washed in commercial washer/extractors is needed. Methods Swatches (1 in. × 1.5 in.) of the outer shell fabrics, Gemini™, Advance™, and Pioneer™, of turnout gear were inoculated with S. aureus, and washed with an Environmental Protection Agency-registered sanitizer commonly used to wash turnout gear. To initially assess the sanitizer, inoculated swatches were washed in small tubes according to the American Society for Testing Materials E2274 Protocol for evaluating laundry sanitizers. Inoculated swatches were also pinned to turnout gear jackets and washed in a Milnor commercial washer/extractor. Viable S. aureus that remained attached to fabric swatches after washing were recovered and quantified. Scanning Electron Microscopy was used to characterize the stages of S. aureus biofilm formation on the swatches that can result in resistance to disinfection. Results Disinfection in small tubes for only 10 s reduced the viability of S. aureus on Gemini™, Advance™, and Pioneer™ by 73, 99, and 100%, respectively. In contrast, disinfection of S. aureus-contaminated Gemini™ swatches pinned to turnout gear and washed in the washer/extractor was 99.7% effective. Scanning Electron Microscopy showed that biofilm formation begins as early as 5 h after attachment of S. aureus. Conclusion This sanitizer and, likely, others containing the anti-microbial agent didecyl dimethyl ammonium chloride, is an effective disinfectant of S. aureus. Inclusion of contaminated outer shell swatches in the wash cycle affords a simple and quantitative method to assess sanitization of gear by commercial gear cleaning facilities. This methodology can be extended to assess for other bacterial contaminants. Sanitizer-resistant strains will continue to pose problems, and biofilm formation may affect the cleanliness of the washed turnout gear. Our methodology for assessing effectiveness of disinfection may help reduce the occupational exposure to fire fighters from bacterial contaminants.
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Affiliation(s)
- Daniel Farcas
- 1Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road M/S L-4020, Morgantown, West Virginia 26505-2888 USA.,2Department of Occupational and Environmental Health Sciences, West Virginia University, Morgantown, West Virginia 26505 USA
| | - Francoise M Blachere
- 1Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road M/S L-4020, Morgantown, West Virginia 26505-2888 USA
| | - Michael L Kashon
- 3Biostatistics and Epidemiology Branch, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, West Virginia 26505 USA
| | - Deborah Sbarra
- 4National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale, Road, Morgantown, West Virginia 26505 USA
| | - Diane Schwegler-Berry
- 5Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, West Virginia 26505 USA
| | - Jeffrey O Stull
- International Personnel Protection, Inc., Box 92493, Austin, TX 78709 USA
| | - John D Noti
- 1Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road M/S L-4020, Morgantown, West Virginia 26505-2888 USA
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16
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Ahrenholz SH, Brueck SE, Rule AM, Noti JD, Noorbakhsh B, Blachere FM, de Perio MA, Lindsley WG, Shaffer RE, Fisher EM. Assessment of environmental and surgical mask contamination at a student health center - 2012-2013 influenza season. J Occup Environ Hyg 2018; 15:664-675. [PMID: 30081757 PMCID: PMC9006334 DOI: 10.1080/15459624.2018.1486509] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/03/2018] [Accepted: 06/04/2018] [Indexed: 05/22/2023]
Abstract
Increased understanding of influenza transmission is critical for pandemic planning and selecting appropriate controls for healthcare personnel safety and health. The goals of this pilot study were to assess environmental contamination in different areas and at two time periods in the influenza season and to determine the feasibility of using surgical mask contamination to evaluate potential exposure to influenza virus. Bioaerosol samples were collected over 12 days (two 6-day sessions) at 12 locations within a student health center using portable two-stage bioaerosol samplers operating 8 hr each day. Surface samples were collected each morning and afternoon from common high-contact non-porous hard surfaces from rooms and locations where bioaerosol samplers were located. Surgical masks worn by participants while in contact with patients with influenza-like illness were collected. A questionnaire administered to each of the 12 participants at the end of each workday and another at the end of each workweek assessed influenza-like illness symptoms, estimated the number of influenza-like illness patient contacts, hand hygiene, and surgical mask usage. All samples were analyzed using qPCR. Over the 12 days of the study, three of the 127 (2.4%) bioaerosol samples, 2 of 483 (0.41%) surface samples, and 0 of 54 surgical masks were positive for influenza virus. For the duration of contact that occurred with an influenza patient on any of the 12 days, nurse practitioners and physicians reported contacts with influenza-like illness patients >60 min, medical assistants reported 15-44 min, and administrative staff reported <30 min. Given the limited number of bioaerosol and surface samples positive for influenza virus in the bioaerosol and surface samples, the absence of influenza virus on the surgical masks provides inconclusive evidence for the potential to use surgical masks to assess exposure to influenza viruses. Further studies are needed to determine feasibility of this approach in assessing healthcare personnel exposures. Information learned in this study can inform future field studies on influenza transmission.
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Affiliation(s)
- Steven H Ahrenholz
- a Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health , Cincinnati , Ohio
| | - Scott E Brueck
- a Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health , Cincinnati , Ohio
| | - Ana M Rule
- b Johns Hopkins University Bloomberg School of Public Health, Environmental Health and Engineering , Baltimore , Maryland
| | - John D Noti
- c Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Bahar Noorbakhsh
- c Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Francoise M Blachere
- c Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Marie A de Perio
- a Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health , Cincinnati , Ohio
| | - William G Lindsley
- c Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Ronald E Shaffer
- d Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Pittsburgh, Pennsylvania
| | - Edward M Fisher
- d Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Pittsburgh, Pennsylvania
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Blachere FM, Lindsley WG, McMillen CM, Beezhold DH, Fisher EM, Shaffer RE, Noti JD. Assessment of influenza virus exposure and recovery from contaminated surgical masks and N95 respirators. J Virol Methods 2018; 260:98-106. [PMID: 30029810 DOI: 10.1016/j.jviromet.2018.05.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [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: 01/26/2018] [Revised: 04/24/2018] [Accepted: 05/15/2018] [Indexed: 12/25/2022]
Abstract
Healthcare workers (HCWs) are at significantly higher risk of exposure to influenza virus during seasonal epidemics and global pandemics. During the 2009 influenza pandemic, some healthcare organizations recommended that HCWs wear respiratory protection such as filtering facepiece respirators, while others indicated that facemasks such as surgical masks (SMs) were sufficient. To assess the level of exposure a HCW may possibly encounter, the aim of this study was to (1.) evaluate if SMs and N95 respirators can serve as "personal bioaerosol samplers" for influenza virus and (2.) determine if SMs and N95 respirators contaminated by influenza laden aerosols can serve as a source of infectious virus for indirect contact transmission. This effort is part of a National Institute for Occupational Safety and Health 5-year multidisciplinary study to determine the routes of influenza transmission in healthcare settings. A coughing simulator was programmed to cough aerosol particles containing influenza virus over a wide concentration range into an aerosol exposure simulation chamber virus/L of exam room air), and a breathing simulator was used to collect virus on either a SM or N95 respirator. Extraction buffers containing nonionic and anionic detergents as well as various protein additives were used to recover influenza virus from the masks and respirators. The inclusion of 0.1% SDS resulted in maximal influenza RNA recovery (41.3%) but with a complete loss of infectivity whereas inclusion of 0.1% bovine serum albumin resulted in reduced RNA recovery (6.8%) but maximal retention of virus infectivity (17.9%). Our results show that a HCW's potential exposure to airborne influenza virus can be assessed in part through analysis of their SMs and N95 respirators, which can effectively serve as personal bioaerosol samplers.
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Affiliation(s)
- Francoise M Blachere
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA.
| | - William G Lindsley
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Cynthia M McMillen
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA; Center for Vaccine Research, Infectious Diseases and Microbiology, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Donald H Beezhold
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Edward M Fisher
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Pittsburgh, PA, USA
| | - Ronald E Shaffer
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Pittsburgh, PA, USA
| | - John D Noti
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
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Blachere FM, Lindsley WG, Weber AM, Beezhold DH, Thewlis RE, Mead KR, Noti JD. Detection of an avian lineage influenza A(H7N2) virus in air and surface samples at a New York City feline quarantine facility. Influenza Other Respir Viruses 2018; 12:613-622. [PMID: 29768714 PMCID: PMC6086858 DOI: 10.1111/irv.12572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2018] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND In December 2016, an outbreak of low pathogenicity avian influenza (LPAI) A(H7N2) occurred in cats at a New York City animal shelter and quickly spread to other shelters in New York and Pennsylvania. The A(H7N2) virus also spread to an attending veterinarian. In response, 500 cats were transferred from these shelters to a temporary quarantine facility for continued monitoring and treatment. OBJECTIVES The objective of this study was to assess the occupational risk of A(H7N2) exposure among emergency response workers at the feline quarantine facility. METHODS Aerosol and surface samples were collected from inside and outside the isolation zones of the quarantine facility. Samples were screened for A(H7N2) by quantitative RT-PCR and analyzed in embryonated chicken eggs for infectious virus. RESULTS H7N2 virus was detected by RT-PCR in 28 of 29 aerosol samples collected in the high-risk isolation (hot) zone with 70.9% on particles with aerodynamic diameters >4 μm, 27.7% in 1-4 μm, and 1.4% in <1 μm. Seventeen of 22 surface samples from the high-risk isolation zone were also H7N2 positive with an average M1 copy number of 1.3 × 103 . Passage of aerosol and surface samples in eggs confirmed that infectious virus was present throughout the high-risk zones in the quarantine facility. CONCLUSIONS By measuring particle size, distribution, and infectivity, our study suggests that the A(H7N2) virus had the potential to spread by airborne transmission and/or direct contact with viral-laden fomites. These results warranted continued A(H7N2) surveillance and transmission-based precautions during the treatment and care of infected cats.
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Affiliation(s)
- Francoise M Blachere
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - William G Lindsley
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Angela M Weber
- Disaster Science Responder Research Program, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Donald H Beezhold
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Robert E Thewlis
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Kenneth R Mead
- Engineering and Physical Hazards Branch, Division of Applied Research and Technology, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH, USA
| | - John D Noti
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
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McMillen CM, Beezhold DH, Blachere FM, Othumpangat S, Kashon ML, Noti JD. Inhibition of influenza A virus matrix and nonstructural gene expression using RNA interference. Virology 2016; 497:171-184. [PMID: 27474950 DOI: 10.1016/j.virol.2016.07.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 12/09/2022]
Abstract
Influenza antiviral drugs that use protein inhibitors can lose their efficacy as resistant strains emerge. As an alternative strategy, we investigated the use of small interfering RNA molecules (siRNAs) by characterizing three siRNAs (M747, M776 and M832) targeting the influenza matrix 2 gene and three (NS570, NS595 and NS615) targeting the nonstructural protein 1 and 2 genes. We also re-examined two previously reported siRNAs, M331 and M950, which target the matrix 1 and 2 genes. Treatment with M331-, M776-, M832-, and M950-siRNAs attenuated influenza titer. M776-siRNA treated cells had 29.8% less infectious virus than cells treated with the previously characterized siRNA, M950. NS570-, NS595- and NS615-siRNAs reduced nonstructural protein 1 and 2 expression and enhanced type I interferon expression by 50%. Combination siRNA treatment attenuated 20.9% more infectious virus than single siRNA treatment. Our results suggest a potential use for these siRNAs as an effective anti-influenza virus therapy.
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Affiliation(s)
- Cynthia M McMillen
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA; Department of Microbiology, Immunology and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, United States
| | - Donald H Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA; Department of Microbiology, Immunology and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, United States
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Sreekumar Othumpangat
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Michael L Kashon
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA; Department of Microbiology, Immunology and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, United States.
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20
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Lindsley WG, Blachere FM, Beezhold DH, Thewlis RE, Noorbakhsh B, Othumpangat S, Goldsmith WT, McMillen CM, Andrew ME, Burrell CN, Noti JD. Viable influenza A virus in airborne particles expelled during coughs versus exhalations. Influenza Other Respir Viruses 2016; 10:404-13. [PMID: 26991074 PMCID: PMC4947941 DOI: 10.1111/irv.12390] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2016] [Indexed: 01/10/2023] Open
Abstract
Background To prepare for a possible influenza pandemic, a better understanding of the potential for the airborne transmission of influenza from person to person is needed. Objectives The objective of this study was to directly compare the generation of aerosol particles containing viable influenza virus during coughs and exhalations. Methods Sixty‐one adult volunteer outpatients with influenza‐like symptoms were asked to cough and exhale three times into a spirometer. Aerosol particles produced during coughing and exhalation were collected into liquid media using aerosol samplers. The samples were tested for the presence of viable influenza virus using a viral replication assay (VRA). Results Fifty‐three test subjects tested positive for influenza A virus. Of these, 28 (53%) produced aerosol particles containing viable influenza A virus during coughing, and 22 (42%) produced aerosols with viable virus during exhalation. Thirteen subjects had both cough aerosol and exhalation aerosol samples that contained viable virus, 15 had positive cough aerosol samples but negative exhalation samples, and 9 had positive exhalation samples but negative cough samples. Conclusions Viable influenza A virus was detected more often in cough aerosol particles than in exhalation aerosol particles, but the difference was not large. Because individuals breathe much more often than they cough, these results suggest that breathing may generate more airborne infectious material than coughing over time. However, both respiratory activities could be important in airborne influenza transmission. Our results are also consistent with the theory that much of the aerosol containing viable influenza originates deep in the lungs.
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Affiliation(s)
- William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Donald H Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Robert E Thewlis
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Bahar Noorbakhsh
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Sreekumar Othumpangat
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - William T Goldsmith
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Cynthia M McMillen
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Michael E Andrew
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Carmen N Burrell
- Department of Emergency Medicine, West Virginia University, Morgantown, WV, USA
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
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Lindsley WG, Noti JD, Blachere FM, Thewlis RE, Martin SB, Othumpangat S, Noorbakhsh B, Goldsmith WT, Vishnu A, Palmer JE, Clark KE, Beezhold DH. Viable influenza A virus in airborne particles from human coughs. J Occup Environ Hyg 2015; 12:107-13. [PMID: 25523206 PMCID: PMC4734406 DOI: 10.1080/15459624.2014.973113] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Patients with influenza release aerosol particles containing the virus into their environment. However, the importance of airborne transmission in the spread of influenza is unclear, in part because of a lack of information about the infectivity of the airborne virus. The purpose of this study was to determine the amount of viable influenza A virus that was expelled by patients in aerosol particles while coughing. Sixty-four symptomatic adult volunteer outpatients were asked to cough 6 times into a cough aerosol collection system. Seventeen of these participants tested positive for influenza A virus by viral plaque assay (VPA) with confirmation by viral replication assay (VRA). Viable influenza A virus was detected in the cough aerosol particles from 7 of these 17 test subjects (41%). Viable influenza A virus was found in the smallest particle size fraction (0.3 μm to 8 μm), with a mean of 142 plaque-forming units (SD 215) expelled during the 6 coughs in particles of this size. These results suggest that a significant proportion of patients with influenza A release small airborne particles containing viable virus into the environment. Although the amounts of influenza A detected in cough aerosol particles during our experiments were relatively low, larger quantities could be expelled by influenza patients during a pandemic when illnesses would be more severe. Our findings support the idea that airborne infectious particles could play an important role in the spread of influenza.
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Affiliation(s)
- William G. Lindsley
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
- Address correspondence to: William G. Lindsley, National Institute for Occupational Safety and Health, 1095 Willowdale Road, M/S 4020, Morgantown, WV 26505-2845; e-mail:
| | - John D. Noti
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Francoise M. Blachere
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Robert E. Thewlis
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Stephen B. Martin
- Field Studies Branch, Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Sreekumar Othumpangat
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Bahar Noorbakhsh
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - William T. Goldsmith
- Pathology and Physiological Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Abhishek Vishnu
- School of Public Health, West Virginia University, Morgantown, West Virginia
| | - Jan E. Palmer
- WELLWVU Student Health, West Virginia University, Morgantown, West Virginia
| | - Karen E. Clark
- WELLWVU Student Health, West Virginia University, Morgantown, West Virginia
| | - Donald H. Beezhold
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
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22
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Fisher EM, Noti JD, Lindsley WG, Blachere FM, Shaffer RE. Validation and application of models to predict facemask influenza contamination in healthcare settings. Risk Anal 2014; 34:1423-34. [PMID: 24593662 PMCID: PMC4485436 DOI: 10.1111/risa.12185] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Facemasks are part of the hierarchy of interventions used to reduce the transmission of respiratory pathogens by providing a barrier. Two types of facemasks used by healthcare workers are N95 filtering facepiece respirators (FFRs) and surgical masks (SMs). These can become contaminated with respiratory pathogens during use, thus serving as potential sources for transmission. However, because of the lack of field studies, the hazard associated with pathogen-exposed facemasks is unknown. A mathematical model was used to calculate the potential influenza contamination of facemasks from aerosol sources in various exposure scenarios. The aerosol model was validated with data from previous laboratory studies using facemasks mounted on headforms in a simulated healthcare room. The model was then used to estimate facemask contamination levels in three scenarios generated with input parameters from the literature. A second model estimated facemask contamination from a cough. It was determined that contamination levels from a single cough (≈19 viruses) were much less than likely levels from aerosols (4,473 viruses on FFRs and 3,476 viruses on SMs). For aerosol contamination, a range of input values from the literature resulted in wide variation in estimated facemask contamination levels (13-202,549 viruses), depending on the values selected. Overall, these models and estimates for facemask contamination levels can be used to inform infection control practice and research related to the development of better facemasks, to characterize airborne contamination levels, and to assist in assessment of risk from reaerosolization and fomite transfer because of handling and reuse of contaminated facemasks.
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Affiliation(s)
- Edward M. Fisher
- National Personal Protective Technology Laboratory, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Pittsburgh, PA, USA
- Address correspondence to Edward Fisher, NPPTL, 626 Cochrans Mill Road, Building 13, Pittsburgh, PA 15236, USA; tel: 412-386-4017;
| | - John D. Noti
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - William G. Lindsley
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Francoise M. Blachere
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Ronald E. Shaffer
- National Personal Protective Technology Laboratory, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Pittsburgh, PA, USA
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Cummings KJ, Martin SB, Lindsley WG, Othumpangat S, Blachere FM, Noti JD, Beezhold DH, Roidad N, Parker JE, Weissman DN. Exposure to influenza virus aerosols in the hospital setting: is routine patient care an aerosol generating procedure? J Infect Dis 2014; 210:504-5. [PMID: 24596280 PMCID: PMC4624392 DOI: 10.1093/infdis/jiu127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
| | | | - William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention
| | - Sreekumar Othumpangat
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention
| | - Donald H Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention
| | - Nasira Roidad
- Department of Medicine, West Virginia University School of Medicine, Morgantown, West Virginia
| | - John E Parker
- Department of Medicine, West Virginia University School of Medicine, Morgantown, West Virginia
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Abstract
Health care workers are exposed to potentially infectious airborne particles while providing routine care to coughing patients. However, much is not understood about the behavior of these aerosols and the risks they pose. We used a coughing patient simulator and a breathing worker simulator to investigate the exposure of health care workers to cough aerosol droplets, and to examine the efficacy of face shields in reducing this exposure. Our results showed that 0.9% of the initial burst of aerosol from a cough can be inhaled by a worker 46 cm (18 inches) from the patient. During testing of an influenza-laden cough aerosol with a volume median diameter (VMD) of 8.5 μm, wearing a face shield reduced the inhalational exposure of the worker by 96% in the period immediately after a cough. The face shield also reduced the surface contamination of a respirator by 97%. When a smaller cough aerosol was used (VMD = 3.4 μm), the face shield was less effective, blocking only 68% of the cough and 76% of the surface contamination. In the period from 1 to 30 minutes after a cough, during which the aerosol had dispersed throughout the room and larger particles had settled, the face shield reduced aerosol inhalation by only 23%. Increasing the distance between the patient and worker to 183 cm (72 inches) reduced the exposure to influenza that occurred immediately after a cough by 92%. Our results show that health care workers can inhale infectious airborne particles while treating a coughing patient. Face shields can substantially reduce the short-term exposure of health care workers to large infectious aerosol particles, but smaller particles can remain airborne longer and flow around the face shield more easily to be inhaled. Thus, face shields provide a useful adjunct to respiratory protection for workers caring for patients with respiratory infections. However, they cannot be used as a substitute for respiratory protection when it is needed. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: tables of the experiments performed, more detailed information about the aerosol measurement methods, photographs of the experimental setup, and summaries of the experimental data from the aerosol measurement devices, the qPCR analysis, and the VPA.].
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Affiliation(s)
- William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
- Address correspondence to: William G. Lindsley, National Institute for Occupational Safety and Health, 1095 Willowdale Road, M/S 4020, Morgantown, WV 26505-2845; e-mail:
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Jonathan V. Szalajda
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Pittsburgh, Pennsylvania
| | - Donald H. Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia
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Othumpangat S, Noti JD, Blachere FM, Beezhold DH. Expression of non-structural-1A binding protein in lung epithelial cells is modulated by miRNA-548an on exposure to influenza A virus. Virology 2013; 447:84-94. [PMID: 24210102 DOI: 10.1016/j.virol.2013.08.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [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: 06/04/2013] [Revised: 06/29/2013] [Accepted: 08/27/2013] [Indexed: 10/26/2022]
Abstract
Understanding the host response to influenza A virus infection is essential for developing intervention approaches. We show that infection of human alveolar epithelial cells and human bronchial epithelial cells with influenza A for 3h resulted in down-regulation of host hsa-miRNA-548an (miRNA-548an) which triggered the overexpression of influenza non-structural-1A binding protein (IVNS1ABP, herein referred to as NS1ABP). Reduced NS1ABP mRNA and NS1ABP protein expression after transfection of miRNA-548an mimic or increased NS1ABP mRNA and NS1ABP protein expression after transfection of miRNA-548an inhibitor provided evidence that miRNA-548an is involved in the regulation of NS1ABP. Transfection of cells with inhibitor led to reduced apoptosis of infected cells while transfection of mimic led to increased apoptosis and reduced influenza copy number suggesting that NS1ABP has a role in viral maintenance. Thus, miRNA-548an may be an important target in controlling the early stage infection of influenza A.
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Affiliation(s)
- Sreekumar Othumpangat
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505-2888, USA
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Noti JD, Blachere FM, McMillen CM, Lindsley WG, Kashon ML, Slaughter DR, Beezhold DH. High humidity leads to loss of infectious influenza virus from simulated coughs. PLoS One 2013; 8:e57485. [PMID: 23460865 PMCID: PMC3583861 DOI: 10.1371/journal.pone.0057485] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 01/22/2013] [Indexed: 12/02/2022] Open
Abstract
Background The role of relative humidity in the aerosol transmission of influenza was examined in a simulated examination room containing coughing and breathing manikins. Methods Nebulized influenza was coughed into the examination room and Bioaerosol samplers collected size-fractionated aerosols (<1 µM, 1–4 µM, and >4 µM aerodynamic diameters) adjacent to the breathing manikin’s mouth and also at other locations within the room. At constant temperature, the RH was varied from 7–73% and infectivity was assessed by the viral plaque assay. Results Total virus collected for 60 minutes retained 70.6–77.3% infectivity at relative humidity ≤23% but only 14.6–22.2% at relative humidity ≥43%. Analysis of the individual aerosol fractions showed a similar loss in infectivity among the fractions. Time interval analysis showed that most of the loss in infectivity within each aerosol fraction occurred 0–15 minutes after coughing. Thereafter, losses in infectivity continued up to 5 hours after coughing, however, the rate of decline at 45% relative humidity was not statistically different than that at 20% regardless of the aerosol fraction analyzed. Conclusion At low relative humidity, influenza retains maximal infectivity and inactivation of the virus at higher relative humidity occurs rapidly after coughing. Although virus carried on aerosol particles <4 µM have the potential for remaining suspended in air currents longer and traveling further distances than those on larger particles, their rapid inactivation at high humidity tempers this concern. Maintaining indoor relative humidity >40% will significantly reduce the infectivity of aerosolized virus.
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Affiliation(s)
- John D Noti
- Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, West Virginia, United States of America.
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Noti JD, Lindsley WG, Blachere FM, Cao G, Kashon ML, Thewlis RE, McMillen CM, King WP, Szalajda JV, Beezhold DH. Detection of infectious influenza virus in cough aerosols generated in a simulated patient examination room. Clin Infect Dis 2012; 54:1569-77. [PMID: 22460981 PMCID: PMC4680957 DOI: 10.1093/cid/cis237] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The potential for aerosol transmission of infectious influenza virus (ie, in healthcare facilities) is controversial. We constructed a simulated patient examination room that contained coughing and breathing manikins to determine whether coughed influenza was infectious and assessed the effectiveness of an N95 respirator and surgical mask in blocking transmission. METHODS National Institute for Occupational Safety and Health aerosol samplers collected size-fractionated aerosols for 60 minutes at the mouth of the breathing manikin, beside the mouth, and at 3 other locations in the room. Total recovered virus was quantitated by quantitative polymerase chain reaction and infectivity was determined by the viral plaque assay and an enhanced infectivity assay. RESULTS Infectious influenza was recovered in all aerosol fractions (5.0% in >4 μm aerodynamic diameter, 75.5% in 1-4 μm, and 19.5% in <1 μm; n = 5). Tightly sealing a mask to the face blocked entry of 94.5% of total virus and 94.8% of infectious virus (n = 3). A tightly sealed respirator blocked 99.8% of total virus and 99.6% of infectious virus (n = 3). A poorly fitted respirator blocked 64.5% of total virus and 66.5% of infectious virus (n = 3). A mask documented to be loosely fitting by a PortaCount fit tester, to simulate how masks are worn by healthcare workers, blocked entry of 68.5% of total virus and 56.6% of infectious virus (n = 2). CONCLUSIONS These results support a role for aerosol transmission and represent the first reported laboratory study of the efficacy of masks and respirators in blocking inhalation of influenza in aerosols. The results indicate that a poorly fitted respirator performs no better than a loosely fitting mask.
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Affiliation(s)
- John D Noti
- Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, WV, USA.
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Lindsley WG, Pearce TA, Hudnall JB, Davis KA, Davis SM, Fisher MA, Khakoo R, Palmer JE, Clark KE, Celik I, Coffey CC, Blachere FM, Beezhold DH. Quantity and size distribution of cough-generated aerosol particles produced by influenza patients during and after illness. J Occup Environ Hyg 2012; 9:443-9. [PMID: 22651099 PMCID: PMC4676262 DOI: 10.1080/15459624.2012.684582] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The question of whether influenza is transmitted to a significant degree by aerosols remains controversial, in part, because little is known about the quantity and size of potentially infectious airborne particles produced by people with influenza. In this study, the size and amount of aerosol particles produced by nine subjects during coughing were measured while they had influenza and after they had recovered, using a laser aerosol particle spectrometer with a size range of 0.35 to 10 μm. Individuals with influenza produce a significantly greater volume of aerosol when ill compared with afterward (p = 0.0143). When the patients had influenza, their average cough aerosol volume was 38.3 picoliters (pL) of particles per cough (SD 43.7); after patients recovered, the average volume was 26.4 pL per cough (SD 45.6). The number of particles produced per cough was also higher when subjects had influenza (average 75,400 particles/cough, SD 97,300) compared with afterward (average 52,200, SD 98,600), although the difference did not reach statistical significance (p = 0.1042). The average number of particles expelled per cough varied widely from patient to patient, ranging from 900 to 302,200 particles/cough while subjects had influenza and 1100 to 308,600 particles/cough after recovery. When the subjects had influenza, an average of 63% of each subject's cough aerosol particle volume in the detection range was in the respirable size fraction (SD 22%), indicating that these particles could reach the alveolar region of the lungs if inhaled by another person. This enhancement in aerosol generation during illness may play an important role in influenza transmission and suggests that a better understanding of this phenomenon is needed to predict the production and dissemination of influenza-laden aerosols by people infected with this virus. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resources: a PDF file of demographic information, influenza test results, and volume and peak flow rate during each cough and a PDF file containing number and size of aerosol particles produced.].
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Affiliation(s)
- William G Lindsley
- National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Morgantown, West Virginia, USA.
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Nayak AP, Green BJ, Janotka E, Blachere FM, Vesper SJ, Beezhold DH, Schmechel D. Production and characterization of IgM monoclonal antibodies against hyphal antigens of Stachybotrys species. Hybridoma (Larchmt) 2011; 30:29-36. [PMID: 21466283 DOI: 10.1089/hyb.2010.0071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Stachybotrys is a hydrophilic fungal genus that is well known for its ability to colonize water-damaged building materials in indoor environments. Personal exposure to Stachybotrys chartarum allergens, mycotoxins, cytolytic peptides, and other immunostimulatory macromolecules has been proposed to exacerbate respiratory morbidity. To date, advances in Stachybotrys detection have focused on the identification of unique biomarkers that can be detected in human serum; however, the availability of immunodiagnostic reagents to Stachybotrys species have been limited. In this study, we report the initial characterization of monoclonal antibodies (MAbs) against a semi-purified cytolytic S. chlorohalonata preparation (cScp) derived from hyphae. BALB/c mice were immunized with cScp and hybridomas were screened against the cScp using an antigen-mediated indirect ELISA. Eight immunoglobulin M MAbs were produced and four were specifically identified in the capture ELISA to react with the cScp. Cross-reactivity of the MAbs was tested against crude hyphal extracts derived from 15 Stachybotrys isolates representing nine Stachybotrys species as well as 39 other environmentally abundant fungi using a capture ELISA. MAb reactivity to spore and hyphal antigens was also tested by a capture ELISA and by fluorescent halogen immunoassay (fHIA). ELISA analysis demonstrated that all MAbs strongly reacted with extracts of S. chartarum but not with extracts of 39 other fungi. However, four MAbs showed cross-reactivity to the phylogenetically related genus Memnoniella. fHIA analysis confirmed that greatest MAb reactivity was ultrastructurally localized in hyphae and phialides. The results of this study further demonstrate the feasibility of specific MAb-based immunoassays for the detection of S. chartarum.
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Affiliation(s)
- Ajay P Nayak
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, Morgantown, WV 26505, USA
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30
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Green BJ, Cummings KJ, Rittenour WR, Hettick JM, Bledsoe TA, Blachere FM, Siegel PD, Gaughan DM, Kullman GJ, Kreiss K, Cox-Ganser J, Beezhold DH. Occupational sensitization to soy allergens in workers at a processing facility. Clin Exp Allergy 2011; 41:1022-30. [PMID: 21545549 DOI: 10.1111/j.1365-2222.2011.03756.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Exposure to soy antigens has been associated with asthma in community outbreaks and in some workplaces. Recently, 135 soy flake processing workers (SPWs) in a Tennessee facility were evaluated for immune reactivity to soy. Allergic sensitization to soy was common and was five times more prevalent than in health care worker controls (HCWs) with no known soy exposure. OBJECTIVE To characterize sensitization to soy allergens in SPWs. METHODS Sera that were positive to soy ImmunoCAP (n=27) were tested in IgE immunoblots. Wild-type (WT) and transgenic (TG) antigens were sequenced using nanoscale Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry (nanoUPLC MS/MS). IgE reactivity towards 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSP), a protein found in TG soy, was additionally investigated. De-identified sera from 50 HCWs were used as a control. RESULTS Immunoblotting of WT and TG soy flake extracts revealed IgE against multiple soy antigens with reactivity towards 48, 54, and 62 kDa bands being the most common. The prominent proteins that bound SPW IgE were identified by nanoUPLC MS/MS analysis to be the high molecular weight soybean storage proteins, β-conglycinin (Gly m 5), and Glycinin (Gly m 6). No specific IgE reactivity could be detected to lower molecular weight soy allergens, Gly m 1 and Gly m 2, in soybean hull (SH) extracts. IgE reactivity was comparable between WT and TG extracts; however, IgE antibodies to CP4-EPSP could not be detected. CONCLUSIONS AND CLINICAL RELEVANCE SPWs with specific IgE to soy reacted most commonly with higher molecular weight soybean storage proteins compared with the lower molecular weight SH allergens identified in community asthma studies. IgE reactivity was comparable between WT and TG soy extracts, while no IgE reactivity to CP4-EPSP was observed. High molecular weight soybean storage allergens, Gly m 5 and Gly m 6, may be respiratory sensitizers in occupational exposed SPWs.
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Affiliation(s)
- B J Green
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505-2888,
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Blachere FM, Cao G, Lindsley WG, Noti JD, Beezhold DH. Enhanced detection of infectious airborne influenza virus. J Virol Methods 2011; 176:120-4. [PMID: 21663766 DOI: 10.1016/j.jviromet.2011.05.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/13/2011] [Accepted: 05/25/2011] [Indexed: 11/26/2022]
Abstract
Current screening methodologies for detecting infectious airborne influenza virus are limited and lack sensitivity. To increase the sensitivity for detecting infectious influenza virus in an aerosol sample, the viral replication assay was developed. With this assay, influenza virus is first amplified by replication in Madin-Darby canine kidney (MDCK) cells followed by detection with quantitative PCR (qPCR). Spanning a 20-h replication period, matrix gene expression levels from infectious virus were measured at several time points using qPCR and found to exponentially increase. Compared with the traditional culture-based viral plaque assay, the viral replication assay resulted in a 4.6 × 10(5) fold increase in influenza virus detection. Furthermore, viral replication assay results were obtained in half the time of the viral plaque assay. To demonstrate that the viral replication assay is capable of detecting airborne influenza virus, dilute preparations of strain A/WS/33 were loaded into a nebulizer, aerosolized within a calm-air settling chamber and subsequently collected using NIOSH Two-Stage Bioaerosol Samplers. At the most diluted concentration corresponding to a chicken embryo infectious dose 50% endpoint (CEID(50)) of 2.8E+02/ml, the viral replication assay was able to detect infectious influenza virus that was otherwise undetectable by viral plaque assay. The results obtained demonstrate that the viral replication assay is highly sensitive at detecting infectious influenza virus from aerosol samples.
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Affiliation(s)
- Francoise M Blachere
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, M.S. 4020, Morgantown, WV 26505-2888, USA.
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32
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Chipinda I, Blachere FM, Anderson SE, Siegel PD. Discrimination of haptens from prohaptens using the metabolically deficient Cprlow/low mouse. Toxicol Appl Pharmacol 2011; 252:268-72. [DOI: 10.1016/j.taap.2011.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 02/16/2011] [Accepted: 02/23/2011] [Indexed: 10/18/2022]
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33
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Lindsley WG, Blachere FM, Thewlis RE, Vishnu A, Davis KA, Cao G, Palmer JE, Clark KE, Fisher MA, Khakoo R, Beezhold DH. Measurements of airborne influenza virus in aerosol particles from human coughs. PLoS One 2010; 5:e15100. [PMID: 21152051 PMCID: PMC2994911 DOI: 10.1371/journal.pone.0015100] [Citation(s) in RCA: 270] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 10/21/2010] [Indexed: 11/23/2022] Open
Abstract
Influenza is thought to be communicated from person to person by multiple pathways. However, the relative importance of different routes of influenza transmission is unclear. To better understand the potential for the airborne spread of influenza, we measured the amount and size of aerosol particles containing influenza virus that were produced by coughing. Subjects were recruited from patients presenting at a student health clinic with influenza-like symptoms. Nasopharyngeal swabs were collected from the volunteers and they were asked to cough three times into a spirometer. After each cough, the cough-generated aerosol was collected using a NIOSH two-stage bioaerosol cyclone sampler or an SKC BioSampler. The amount of influenza viral RNA contained in the samplers was analyzed using quantitative real-time reverse-transcription PCR (qPCR) targeting the matrix gene M1. For half of the subjects, viral plaque assays were performed on the nasopharyngeal swabs and cough aerosol samples to determine if viable virus was present. Fifty-eight subjects were tested, of whom 47 were positive for influenza virus by qPCR. Influenza viral RNA was detected in coughs from 38 of these subjects (81%). Thirty-five percent of the influenza RNA was contained in particles>4 µm in aerodynamic diameter, while 23% was in particles 1 to 4 µm and 42% in particles<1 µm. Viable influenza virus was detected in the cough aerosols from 2 of 21 subjects with influenza. These results show that coughing by influenza patients emits aerosol particles containing influenza virus and that much of the viral RNA is contained within particles in the respirable size range. The results support the idea that the airborne route may be a pathway for influenza transmission, especially in the immediate vicinity of an influenza patient. Further research is needed on the viability of airborne influenza viruses and the risk of transmission.
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Affiliation(s)
- William G Lindsley
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia, United States of America.
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Cummings KJ, Gaughan DM, Kullman GJ, Beezhold DH, Green BJ, Blachere FM, Bledsoe T, Kreiss K, Cox-Ganser J. Adverse respiratory outcomes associated with occupational exposures at a soy processing plant. Eur Respir J 2010; 36:1007-15. [PMID: 20413546 DOI: 10.1183/09031936.00151109] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This study aimed to characterise the relationship between adverse health outcomes and occupational risk factors among workers at a soy processing plant. A questionnaire, spirometry, methacholine challenge, immune testing and air sampling for dust and soy were offered. Prevalence ratios (PRs) of respiratory problems from comparisons with the US adult population were calculated. Soy-specific immunoglobulin (Ig)G and IgE among participants and healthcare worker controls were compared. Associations between health outcomes and potential explanatory variables were examined using logistic regression. 147 (52%) out of 281 employees, including 66 (70%) out of 94 production workers, participated. PRs were significantly elevated for wheeze, sinusitis, ever-asthma and current asthma. Participants had significantly higher mean concentrations of soy-specific IgG (97.9 mg·L(-1) versus 1.5 mg·L(-1)) and prevalence of soy-specific IgE (21% versus 4%) than controls. Participants with soy-specific IgE had three-fold greater odds of current asthma or asthma-like symptoms, and six-fold greater odds of work-related asthma-like symptoms; the latter additionally was associated with production work and higher peak dust exposures. Airways obstruction was associated with higher peak dust. Work-related sinusitis, nasal allergies and rash were associated with reported workplace mould exposure. Asthma and symptoms of asthma, but not other respiratory problems, were associated with immune reactivity to soy.
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Affiliation(s)
- K J Cummings
- Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA.
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35
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Lindsley WG, Blachere FM, Davis KA, Pearce TA, Fisher MA, Khakoo R, Davis SM, Rogers ME, Thewlis RE, Posada JA, Redrow JB, Celik IB, Chen BT, Beezhold DH. Distribution of airborne influenza virus and respiratory syncytial virus in an urgent care medical clinic. Clin Infect Dis 2010; 50:693-8. [PMID: 20100093 DOI: 10.1086/650457] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Considerable controversy exists with regard to whether influenza virus and respiratory syncytial virus (RSV) are spread by the inhalation of infectious airborne particles and about the importance of this route, compared with droplet or contact transmission. METHODS Airborne particles were collected in an urgent care clinic with use of stationary and personal aerosol samplers. The amounts of airborne influenza A, influenza B, and RSV RNA were determined using real-time quantitative polymerase chain reaction. Health care workers and patients participating in the study were tested for influenza. RESULTS Seventeen percent of the stationary samplers contained influenza A RNA, 1% contained influenza B RNA, and 32% contained RSV RNA. Nineteen percent of the personal samplers contained influenza A RNA, none contained influenza B RNA, and 38% contained RSV RNA. The number of samplers containing influenza RNA correlated well with the number and location of patients with influenza (r= 0.77). Forty-two percent of the influenza A RNA was in particles < or = 4.1 microm in aerodynamic diameter, and 9% of the RSV RNA was in particles < or = 4.1 microm. CONCLUSIONS Airborne particles containing influenza and RSV RNA were detected throughout a health care facility. The particles were small enough to remain airborne for an extended time and to be inhaled deeply into the respiratory tract. These results support the possibility that influenza and RSV can be transmitted by the airborne route and suggest that further investigation of the potential of these particles to transmit infection is warranted.
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Affiliation(s)
- William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia 26505-2845, USA.
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Petrick JS, Blachere FM, Selmin O, Lantz RC. Inorganic arsenic as a developmental toxicant: in utero exposure and alterations in the developing rat lungs. Mol Nutr Food Res 2009; 53:583-91. [PMID: 19072884 DOI: 10.1002/mnfr.200800019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the present study, we characterize the toxic effects of in utero arsenic exposure on the developing lung. We hypothesize that in utero exposure to inorganic arsenic through maternal drinking water causes altered gene and protein expression in the developing lung, indicative of downstream molecular and functional changes. From conception to embryonic day 18, we exposed pregnant Sprague-Dawley rats to 500 ppb arsenic (as arsenite) via the drinking water. Subtracted cDNA libraries comparing control to arsenic exposed embryonic lungs were generated. In addition, a broad Western blot analysis was performed to identify altered protein expression. A total of 59 genes and 34 proteins were identified as being altered. Pathway mapping and analysis showed that cell motility was the process most affected. The most likely affected pathway was alteration in integrin signaling through the beta-catenin pathway, altering c-myc. The present study shows that arsenic induces alterations in the developing lung. These data may be useful in the elucidation of molecular targets and biomarkers of arsenic exposure during lung development and may aid in understanding the etiology of arsenic induced adult respiratory disease and lung cancers.
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Affiliation(s)
- Jay S Petrick
- Department of Pharmacology and Toxicology, The University of Arizona, Tucson, AZ 85724-5044, USA
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37
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Hettick JM, Green BJ, Buskirk AD, Kashon ML, Slaven JE, Janotka E, Blachere FM, Schmechel D, Beezhold DH. Discrimination of Penicillium isolates by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry fingerprinting. Rapid Commun Mass Spectrom 2008; 22:2555-2560. [PMID: 18646251 DOI: 10.1002/rcm.3649] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to generate highly reproducible mass spectral 'fingerprints' for twelve Penicillium species. Prior to MALDI-TOF MS analysis, eight replicate cultures of each Penicillium species were subjected to three one-minute bead-beating cycles in an acetonitrile/trifluoroacetic acid solvent. The mass spectra contained abundant peaks in the range of m/z 5000-20 000, and allowed unambiguous discrimination between species. In addition, a biomarker common to all Penicillium mass spectra was observed at m/z 13 900. Discriminant analysis using the MALDI-TOF MS data yielded classification error rates of 0% (i.e. 100% correct identification), indicating that MALDI-TOF MS data may be a useful diagnostic tool for the objective identification of Penicillium species of environmental and clinical importance.
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Affiliation(s)
- Justin M Hettick
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Health Effects Laboratory Division, 1095 Willowdale Road, Morgantown, WV 26505, USA.
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Beezhold DH, Green BJ, Blachere FM, Schmechel D, Weissman DN, Velickoff D, Hogan MB, Wilson NW. Prevalence of allergic sensitization to indoor fungi in West Virginia. Allergy Asthma Proc 2008; 29:29-34. [PMID: 18302835 DOI: 10.2500/aap2008.29.3076] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Exposure to indoor fungi is of growing concern in residential and occupational environments in the United States. The purpose of this study was to determine the prevalence of sensitization to common indoor fungal species in an atopic population. We evaluated 102 patients (73 female and 29 male patients) for immunoglobulin E (IgE) reactivity to a panel of skin-prick test (SPT) reagents used for routine allergy testing. Patients also were tested for six additional fungi that are common indoor contaminants. All patients had symptoms consistent with allergic rhinitis or asthma. The presence of specific IgE against the fungal species was determined using immunoblotting. Of the 102 eligible patients, 68% had at least one positive skin test. The most prevalent positive SPTs were to dust mites, cats, vernal grass, and short ragweed. Overall, 21/102 (21%) patients with asthma or allergic rhinitis were skin test positive to at least one fungal extract. Of the patients with a positive SPT to fungi, 12/21 (58%) showed sensitivity to one or more of the newly tested species; most notably Trichoderma viride (8%), Chaetomium globosum (7%), Paecilomyces variotii (7%), and Acremonium strictum (6%). Immunoblotting revealed specific IgE against a number of protein bands belonging to these fungal species. The prevalence of fungal sensitization was common, particularly for indoor fungal contaminants that are not routinely included in SPT panels. Cross-reactivity with other fungi may partially explain our results; however, skin testing for these indoor fungi may provide useful diagnostic information.
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Affiliation(s)
- Donald H. Beezhold
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Brett J. Green
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Francoise M. Blachere
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Detlef Schmechel
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - David N. Weissman
- Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Deborah Velickoff
- Department of Pediatrics, Allergy and Immunology, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Mary Beth Hogan
- Department of Pediatrics, Allergy and Immunology, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Nevin W. Wilson
- Department of Pediatrics, Allergy and Immunology, West Virginia University School of Medicine, Morgantown, West Virginia
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Schmechel D, Green BJ, Blachere FM, Janotka E, Beezhold DH. Analytical bias of cross-reactive polyclonal antibodies for environmental immunoassays of Alternaria alternata. J Allergy Clin Immunol 2007; 121:763-8. [PMID: 18036643 DOI: 10.1016/j.jaci.2007.09.046] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 09/21/2007] [Accepted: 09/24/2007] [Indexed: 11/16/2022]
Abstract
BACKGROUND Alternaria alternata is recognized as an important aeroallergen indoors and outdoors, and exposure to the fungus has been identified as a risk factor for asthma. Two recent publications concluded that 95% to 99% of American homes contained detectable amounts of Alternaria antigens when analyzed with a polyclonal antibody (pAb)-based ELISA. OBJECTIVES We investigated the cross-reactivity of the commercially available pAbs that were used in those studies. METHODS Reactivity to 24 fungal species commonly found in indoor environments was analyzed by inhibition ELISA by using solid-phase A alternata antigen. The pAbs were also tested by immunoblotting and halogen immunoassay for a subgroup of fungi. RESULTS Spores of 7 fungi including species of Alternaria, Ulocladium, Stemphylium, Epicoccum, Drechslera, and Exserohilum strongly inhibited the binding of the pAbs when tested by ELISA. Six other fungi reacted in the ELISA at a lower level, and 11 fungal species including several Penicillium, Aspergillus, Fusarium, and Cladosporium species failed to show inhibition. The immunoblots and the halogen immunoassay staining confirmed the cross-reactivity patterns of the ELISA. CONCLUSION The pAbs against A alternata were found to cross-react broadly with related and nonrelated fungi. The prevalence data previously reported for A alternata should be considered to be fungal-reactive rather than A alternata-specific.
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Affiliation(s)
- Detlef Schmechel
- Allergy and Clinical Immunology Branch, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
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Abstract
Exposure to fungi, particularly in water damaged indoor environments, has been thought to exacerbate a number of adverse health effects, ranging from subjective symptoms such as fatigue, cognitive difficulties or memory loss to more definable diseases such as allergy, asthma and hypersensitivity pneumonitis. Understanding the role of fungal exposure in these environments has been limited by methodological difficulties in enumerating and identifying various fungal components in environmental samples. Consequently, data on personal exposure and sensitization to fungal allergens are mainly based on the assessment of a few select and easily identifiable species. The contribution of other airborne spores, hyphae and fungal fragments to exposure and allergic sensitization are poorly characterized. There is increased interest in the role of aerosolized fungal fragments following reports that the combination of hyphal fragments and spore counts improved the association with asthma severity. These fragments are particles derived from any intracellular or extracellular fungal structure and are categorized as either submicron particles or larger fungal fragments. In vitro studies have shown that submicron particles of several fungal species are aerosolized in much higher concentrations (300-500 times) than spores, and that respiratory deposition models suggest that such fragments of Stachybotrys chartarum may be deposited in 230-250 fold higher numbers than spores. The practical implications of these models are yet to be clarified for human exposure assessments and clinical disease. We have developed innovative immunodetection techniques to determine the extent to which larger fungal fragments, including hyphae and fractured conidia, function as aeroallergen sources. These techniques were based on the Halogen Immunoassay (HIA), an immunostaining technique that detects antigens associated with individual airborne particles >1 microm, with human serum immunoglobulin E (IgE). Our studies demonstrated that the numbers of total airborne hyphae were often significantly higher in concentration than conidia of individual allergenic genera. Approximately 25% of all hyphal fragments expressed detectable allergen and the resultant localization of IgE immunostaining was heterogeneous among the hyphae. Furthermore, conidia of ten genera that were previously uncharacterized could be identified as sources of allergens. These findings highlight the contribution of larger fungal fragments as aeroallergen sources and present a new paradigm of fungal exposure. Direct evidence of the associations between fungal fragments and building-related disease is lacking and in order to gain a better understanding, it will be necessary to develop diagnostic reagents and detection methods, particularly for submicron particles. Assays using monoclonal antibodies enable the measurement of individual antigens but interpretation can be confounded by cross-reactivity between fungal species. The recent development of species-specific monoclonal antibodies, used in combination with a fluorescent-confocal HIA technique should, for the first time, enable the speciation of morphologically indiscernible fungal fragments. The application of this novel method will help to characterize the contribution of fungal fragments to adverse health effects due to fungi and provide patient-specific exposure and sensitization profiles.
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Affiliation(s)
- Brett J Green
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia 26505-2888, USA.
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Abstract
BACKGROUND Influenza virus was used to characterize the efficacy of a cyclone-based, two-stage personal bioaerosol sampler for the collection and size fractionation of aerosolized viral particles. METHODS A Collison single-jet nebulizer was used to aerosolize the attenuated FluMist vaccine into a calm-air settling chamber. Viral particles were captured with bioaerosol samplers that utilize 2 microcentrifuge tubes to collect airborne particulates. The first tube (T1) collects particles greater than 1.8 microm in diameter, while the second tube (T2) collects particles between 1.0 and 1.8 microm, and the back-up filter (F) collects submicron particles. Following aerosolization, quantitative PCR was used to detect and quantify H1N1 and H3N2 influenza strains. RESULTS Based on qPCR results, we demonstrate that aerosolized viral particles were efficiently collected and separated according to aerodynamic size using the two-stage bioaerosol sampler. Most viral particles were collected in T2 (1-1.8 microm) and on the back-up filter (< 1 microm) of the bioaerosol sampler. Furthermore, we found that the detection of viral particles with the two-stage sampler was directly proportional to the collection time. Consequently, viral particle counts were significantly greater at 40 minutes in comparison to 5, 10 and 20 minute aerosol collection points. CONCLUSIONS Due to a lack of empirical data, aerosol transmission of influenza is often questioned. Using FluMist, we demonstrated that a newly developed bioaerosol sampler is able to recover and size fractionate aerosolized viral particles. This sampler should be an important tool for studying viral transmission in clinical settings and may significantly contribute towards understanding the modes of influenza virus transmission.
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Affiliation(s)
- Francoise M Blachere
- Centers for Disease Control, National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Allergy and Clinical Immunology Branch, Morgantown, WV 26505, USA.
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Green BJ, Millecchia LL, Blachere FM, Tovey ER, Beezhold DH, Schmechel D. Dual fluorescent halogen immunoassay for bioaerosols using confocal microscopy. Anal Biochem 2006; 354:151-3. [PMID: 16712767 DOI: 10.1016/j.ab.2006.03.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 02/19/2006] [Accepted: 03/20/2006] [Indexed: 11/28/2022]
Affiliation(s)
- Brett J Green
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA.
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Selmin O, Thorne PA, Blachere FM, Johnson PD, Romagnolo DF. Transcriptional activation of the membrane-bound progesterone receptor (mPR) by dioxin, in endocrine-responsive tissues. Mol Reprod Dev 2005; 70:166-74. [PMID: 15570619 DOI: 10.1002/mrd.20090] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We originally identified the membrane-bound progesterone receptor (mPR) using a screening for genes differentially expressed in liver of rats exposed to dioxin. Recent findings have suggested a role for the mPR in sperm cells, ovary, and brain; however, its mechanisms of action are largely unknown. In this study, we examined the expression pattern of the mPR in liver of rats exposed to dioxin and identified possible mechanisms of its regulation. We observed that mPR expression was induced by dioxin, but was also dependent on the hormonal responsiveness of the tissue. In particular, in male, but not female liver, dioxin induced the expression of the mPR. However, in control, untreated female liver the level of mPR transcript was higher than in control males. Moreover, in breast cancer cells MCF-7 dioxin induced mPR expression. Promoter studies using the luciferase assay indicated that a fragment of approximately 350 bp of the mPR promoter was able to induce luciferase activity in the presence of dioxin, suggesting that the presumptive XREs sites contained in this mPR promoter region are responsive to dioxin. Analysis of mPR protein level confirmed the results observed at the RNA level, both in rat liver and MCF-7 cells. Taken together, these observations suggest the existence of a novel cross-talk between steroid and aromatic hydrocarbon receptors (AhR), and underline the importance of the mPR as a mediator of physiologic effects of the sex hormones.
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Affiliation(s)
- Ornella Selmin
- Department of Veterinary Sciences and Microbiology, University of Arizona, Tucson, AZ 87524, USA.
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