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Li Y, Li J, Zhu Z, Zeng W, Zhu Q, Rong Z, Hu J, Li X, He G, Zhao J, Yin L, Quan Y, Zhang Q, Li M, Zhang L, Zhou Y, Liu T, Ma W, Zeng S, Chen Q, Sun L, Xiao J. Exposure-response relationship between temperature, relative humidity, and varicella: a multicity study in South China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:7594-7604. [PMID: 36044136 DOI: 10.1007/s11356-022-22711-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023]
Abstract
Varicella is a rising public health issue. Several studies have tried to quantify the relationships between meteorological factors and varicella incidence but with inconsistent results. We aim to investigate the impact of temperature and relative humidity on varicella, and to further explore the effect modification of these relationships. In this study, the data of varicella and meteorological factors from 2011 to 2019 in 21 cities of Guangdong Province, China were collected. Distributed lag nonlinear models (DLNM) were constructed to explore the relationship between meteorological factors (temperature and relative humidity) and varicella in each city, controlling in school terms, holidays, seasonality, long-term trends, and day of week. Multivariate meta-analysis was applied to pool the city-specific estimations. And the meta-regression was used to explore the effect modification for the spatial heterogeneity of city-specific meteorological factors and social factors (such as disposable income per capita, vaccination coverage, and so on) on varicella. The results indicated that the relationship between temperature and varicella in 21 cities appeared nonlinear with an inverted S-shaped. The relative risk peaked at 20.8 ℃ (RR = 1.42, 95% CI: 1.22, 1.65). The relative humidity-varicella relationship was approximately L-shaped, with a peaking risk at 69.5% relative humidity (RR = 1.25, 95% CI: 1.04, 1.50). The spatial heterogeneity of temperature-varicella relationships may be caused by income or varicella vaccination coverage. And varicella vaccination coverage may contribute to the spatial heterogeneity of the relative humidity-varicella relationship. The findings can help us deepen the understanding of the meteorological factors-varicella association and provide evidence for developing prevention strategy for varicella epidemic.
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Affiliation(s)
- Yihan Li
- School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong, China
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Jialing Li
- Institute of Immunization Program, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Zhihua Zhu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Weilin Zeng
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Qi Zhu
- Institute of Immunization Program, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Zuhua Rong
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Jianxiong Hu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Xing Li
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Guanhao He
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Jianguo Zhao
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Lihua Yin
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Yi Quan
- School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong, China
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Qian Zhang
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Manman Li
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Li Zhang
- School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong, China
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Yan Zhou
- School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong, China
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Tao Liu
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Wenjun Ma
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Siqing Zeng
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Qing Chen
- School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Limei Sun
- Institute of Immunization Program, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China
| | - Jianpeng Xiao
- School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong, China.
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, 511430, Guangdong, China.
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Thornton GM, Fleck BA, Dandnayak D, Kroeker E, Zhong L, Hartling L. The impact of heating, ventilation and air conditioning (HVAC) design features on the transmission of viruses, including the 2019 novel coronavirus (COVID-19): A systematic review of humidity. PLoS One 2022; 17:e0275654. [PMID: 36215321 PMCID: PMC9550073 DOI: 10.1371/journal.pone.0275654] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 09/21/2022] [Indexed: 11/06/2022] Open
Abstract
The aerosol route has been a pathway for transmission of many viruses. Similarly, recent evidence has determined aerosol transmission for SARS-CoV-2 to be significant. Consequently, public health officials and professionals have sought data regarding the role of Heating, Ventilation, and Air Conditioning (HVAC) features as a means to mitigate transmission of viruses, particularly coronaviruses. Using international standards, a systematic review was conducted to comprehensively identify and synthesize research examining the effect of humidity on transmission of coronaviruses and influenza. The results from 24 relevant studies showed that: increasing from mid (40–60%) to high (>60%) relative humidity (RH) for SARS-CoV-2 was associated with decreased virus survival; although SARS-CoV-2 results appear consistent, coronaviruses do not all behave the same; increasing from low (<40%) to mid RH for influenza was associated with decreased persistence, infectivity, viability, and survival, however effects of increased humidity from mid to high for influenza were not consistent; and medium, temperature, and exposure time were associated with inconsistency in results for both coronaviruses and influenza. Adapting humidity to mitigate virus transmission is complex. When controlling humidity as an HVAC feature, practitioners should take into account virus type and temperature. Future research should also consider the impact of exposure time, temperature, and medium when designing experiments, while also working towards more standardized testing procedures. Clinical trial registration: PROSPERO 2020 CRD42020193968.
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Affiliation(s)
- Gail M. Thornton
- Department of Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada
| | - Brian A. Fleck
- Department of Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada
- * E-mail:
| | - Dhyey Dandnayak
- Department of Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada
| | - Emily Kroeker
- Department of Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada
| | - Lexuan Zhong
- Department of Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada
| | - Lisa Hartling
- Alberta Research Centre for Health Evidence, Department of Pediatrics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Canada
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3
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Li Y, Wu C, Cao G, Guan D, Zhan C. Transmission characteristics of respiratory droplets aerosol in indoor environment: an experimental study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2022; 32:1768-1779. [PMID: 33825604 DOI: 10.1080/09603123.2021.1910629] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
Transmission of droplets has been recognized as an important form of infection for the respiratory diseases. This study investigated the distribution of human respiratory droplets and assessed the effects of air change rate and generated velocity on droplet transmission using an active agent in an enclosed chamber (46 m3). Results revealed that the higher the air change rate was, the fewer viable droplets were detected in the range of <3.3 μm with ventilation; an increased air change rate can increase the attenuation of droplet aerosol. Without ventilation, the viable droplet size was observed to mainly distribute greater than 3.3 μm, which occupied up 87.5% of the total number. When the generated velocity was increased to 20 m/s, 29.38% of the viable droplets were detected at the position of 2.0 m. The findings are excepted to be useful for developing the technology of reducing droplet propagation and providing data verification for simulation research.
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Affiliation(s)
- Yanju Li
- School of Energy and Safety Engineering, Tianjin Chengjian University, Tianjin, China
| | - Chunbin Wu
- School of Energy and Safety Engineering, Tianjin Chengjian University, Tianjin, China
| | - Guoqing Cao
- Institute of Building Environment and Energy, China Academy of Building Research, Beijing, China
| | - Dexing Guan
- School of Energy and Safety Engineering, Tianjin Chengjian University, Tianjin, China
| | - Chaoguo Zhan
- School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin, China
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4
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Ates HC, Nguyen PQ, Gonzalez-Macia L, Morales-Narváez E, Güder F, Collins JJ, Dincer C. End-to-end design of wearable sensors. NATURE REVIEWS. MATERIALS 2022; 7:887-907. [PMID: 35910814 PMCID: PMC9306444 DOI: 10.1038/s41578-022-00460-x] [Citation(s) in RCA: 173] [Impact Index Per Article: 86.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/15/2022] [Indexed: 05/03/2023]
Abstract
Wearable devices provide an alternative pathway to clinical diagnostics by exploiting various physical, chemical and biological sensors to mine physiological (biophysical and/or biochemical) information in real time (preferably, continuously) and in a non-invasive or minimally invasive manner. These sensors can be worn in the form of glasses, jewellery, face masks, wristwatches, fitness bands, tattoo-like devices, bandages or other patches, and textiles. Wearables such as smartwatches have already proved their capability for the early detection and monitoring of the progression and treatment of various diseases, such as COVID-19 and Parkinson disease, through biophysical signals. Next-generation wearable sensors that enable the multimodal and/or multiplexed measurement of physical parameters and biochemical markers in real time and continuously could be a transformative technology for diagnostics, allowing for high-resolution and time-resolved historical recording of the health status of an individual. In this Review, we examine the building blocks of such wearable sensors, including the substrate materials, sensing mechanisms, power modules and decision-making units, by reflecting on the recent developments in the materials, engineering and data science of these components. Finally, we synthesize current trends in the field to provide predictions for the future trajectory of wearable sensors.
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Affiliation(s)
- H. Ceren Ates
- FIT Freiburg Center for Interactive Materials and Bioinspired Technology, University of Freiburg, Freiburg, Germany
- IMTEK – Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Peter Q. Nguyen
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA USA
| | | | - Eden Morales-Narváez
- Biophotonic Nanosensors Laboratory, Centro de Investigaciones en Óptica, León, Mexico
| | - Firat Güder
- Department of Bioengineering, Imperial College London, London, UK
| | - James J. Collins
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA USA
- Institute of Medical Engineering & Science, Department of Biological Engineering, MIT, Cambridge, MA USA
- Broad Institute of MIT and Harvard, Cambridge, MA USA
| | - Can Dincer
- FIT Freiburg Center for Interactive Materials and Bioinspired Technology, University of Freiburg, Freiburg, Germany
- IMTEK – Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
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An Assessment of Airborne Bacteria and Fungi in the Female Dormitory Environment: Level, Impact Factors and Dose Rate. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19116642. [PMID: 35682227 PMCID: PMC9180550 DOI: 10.3390/ijerph19116642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/18/2022] [Accepted: 05/27/2022] [Indexed: 11/17/2022]
Abstract
In this study, the levels of airborne bacteria and fungi were tested in a female dormitory room; the effects of heating, relative humidity and number of occupants on indoor microorganisms were analyzed and the dose rate of exposure to microbes was assessed. The bacterial and fungal concentrations in the room ranged from 100 to several thousand CFU/m3, and the highest counts were observed in the morning (930 ± 1681 CFU/m3). Staphylococcus spp. and Micrococcus spp. were found in the dormitory. When the heating was on, the total bacterial and fungal counts were lower than when there was no heating. Moreover, statistically significant differences were observed for bacterial concentrations during the morning periods between the times when there was no heating and the times when there was heating. The number of occupants had an obvious positive effect on the total bacterial counts. Moreover, RH had no correlation with the airborne fungi in the dormitory, statistically. Furthermore, the highest dose rate from exposure to bacteria and fungi was observed during sleeping hours. The dose rate from exposure to airborne microorganisms in the dormitory was associated with the activity level in the room. These results helped to elucidate the threat of bioaerosols to the health of female occupants and provide guidance for protective measures.
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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] [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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Ahmed T, Wendling HE, Mofakham AA, Ahmadi G, Helenbrook BT, Ferro AR, Brown DM, Erath BD. Variability in expiratory trajectory angles during consonant production by one human subject and from a physical mouth model: Application to respiratory droplet emission. INDOOR AIR 2021; 31:1896-1912. [PMID: 34297885 PMCID: PMC8447379 DOI: 10.1111/ina.12908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 07/03/2021] [Accepted: 07/05/2021] [Indexed: 06/10/2023]
Abstract
The COVID-19 pandemic has highlighted the need to improve understanding of droplet transport during expiratory emissions. While historical emphasis has been placed on violent events such as coughing and sneezing, the recognition of asymptomatic and presymptomatic spread has identified the need to consider other modalities, such as speaking. Accurate prediction of infection risk produced by speaking requires knowledge of both the droplet size distributions that are produced, as well as the expiratory flow fields that transport the droplets into the surroundings. This work demonstrates that the expiratory flow field produced by consonant productions is highly unsteady, exhibiting extremely broad inter- and intra-consonant variability, with mean ejection angles varying from ≈+30° to -30°. Furthermore, implementation of a physical mouth model to quantify the expiratory flow fields for fricative pronunciation of [f] and [θ] demonstrates that flow velocities at the lips are higher than previously predicted, reaching 20-30 m/s, and that the resultant trajectories are unstable. Because both large and small droplet transport are directly influenced by the magnitude and trajectory of the expirated air stream, these findings indicate that prior investigations of the flow dynamics during speech have largely underestimated the fluid penetration distances that can be achieved for particular consonant utterances.
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Affiliation(s)
- Tanvir Ahmed
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew YorkUSA
| | - Hannah E. Wendling
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew YorkUSA
| | - Amir A. Mofakham
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew YorkUSA
| | - Goodarz Ahmadi
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew YorkUSA
| | - Brian T. Helenbrook
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew YorkUSA
| | - Andrea R. Ferro
- Department of Civil and Environmental EngineeringClarkson UniversityPotsdamNew YorkUSA
| | - Deborah M. Brown
- Joint Educational ProgramsTrudeau InstituteSaranac LakeNew YorkUSA
| | - Byron D. Erath
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew YorkUSA
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Asadi S, Tupas MJ, Barre RS, Wexler AS, Bouvier NM, Ristenpart WD. Non-respiratory particles emitted by guinea pigs in airborne disease transmission experiments. Sci Rep 2021; 11:17490. [PMID: 34471147 PMCID: PMC8410799 DOI: 10.1038/s41598-021-96678-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 08/02/2021] [Indexed: 02/02/2023] Open
Abstract
Animal models are often used to assess the airborne transmissibility of various pathogens, which are typically assumed to be carried by expiratory droplets emitted directly from the respiratory tract of the infected animal. We recently established that influenza virus is also transmissible via "aerosolized fomites," micron-scale dust particulates released from virus-contaminated surfaces (Asadi et al. in Nat Commun 11(1):4062, 2020). Here we expand on this observation, by counting and characterizing the particles emitted from guinea pig cages using an Aerodynamic Particle Sizer (APS) and an Interferometric Mie Imaging (IMI) system. Of over 9000 airborne particles emitted from guinea pig cages and directly imaged with IMI, none had an interference pattern indicative of a liquid droplet. Separate measurements of the particle count using the APS indicate that particle concentrations spike upwards immediately following animal motion, then decay exponentially with a time constant commensurate with the air exchange rate in the cage. Taken together, the results presented here raise the possibility that a non-negligible fraction of airborne influenza transmission events between guinea pigs occurs via aerosolized fomites rather than respiratory droplets, though the relative frequencies of these two routes have yet to be definitively determined.
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Affiliation(s)
- Sima Asadi
- grid.27860.3b0000 0004 1936 9684Department of Chemical Engineering, University of California Davis, One Shields Ave., Davis, CA 95616 USA ,grid.116068.80000 0001 2341 2786Present Address: Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Manilyn J. Tupas
- grid.27860.3b0000 0004 1936 9684Department of Chemical Engineering, University of California Davis, One Shields Ave., Davis, CA 95616 USA
| | - Ramya S. Barre
- grid.59734.3c0000 0001 0670 2351Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029 USA ,grid.16750.350000 0001 2097 5006Present Address: Department of Ecology and Evolutionary Biology, 304 Guyot Hall, Princeton University, Princeton, NJ 08544 USA
| | - Anthony S. Wexler
- grid.27860.3b0000 0004 1936 9684Department of Mechanical and Aerospace Engineering, University of California Davis, One Shields Ave., Davis, CA 95616 USA ,grid.27860.3b0000 0004 1936 9684Air Quality Research Center, University of California Davis, One Shields Ave., Davis, CA 95616 USA ,grid.27860.3b0000 0004 1936 9684Department of Civil and Environmental Engineering, University of California Davis, One Shields Ave., Davis, CA 95616 USA ,grid.27860.3b0000 0004 1936 9684Department of Land, Air and Water Resources, University of California Davis, One Shields Ave., Davis, CA 95616 USA
| | - Nicole M. Bouvier
- grid.59734.3c0000 0001 0670 2351Department of Microbiology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029 USA ,grid.59734.3c0000 0001 0670 2351Department of Medicine, Div. of Infectious Diseases, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029 USA
| | - William D. Ristenpart
- grid.27860.3b0000 0004 1936 9684Department of Chemical Engineering, University of California Davis, One Shields Ave., Davis, CA 95616 USA
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Effect of Train-Induced Wind on the Transmission of COVID-19: A New Insight into Potential Infectious Risks. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18158164. [PMID: 34360459 PMCID: PMC8345946 DOI: 10.3390/ijerph18158164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/07/2021] [Accepted: 07/21/2021] [Indexed: 12/16/2022]
Abstract
The unprecedented COVID-19 pandemic has caused a traffic tie-up across the world. In addition to home quarantine orders and travel bans, the social distance guideline of about six feet was enacted to reduce the risk of contagion. However, with recent life gradually returning to normal, the crisis is not over. In this research, a moving train test and a Gaussian puff model were employed to investigate the impact of wind raised by a train running on the transmission and dispersion of SARS-CoV-2 from infected individuals. Our findings suggest that the 2 m social distance guideline may not be enough; under train-induced wind action, human respiratory disease-carrier droplets may travel to unexpected places. However, there are deficiencies in passenger safety guidelines and it is necessary to improve the quantitative research in the relationship between train-induced wind and virus transmission. All these findings could provide a fresh insight to contain the spread of COVID-19 and provide a basis for preventing and controlling the pandemic virus, and probe into strategies for control of the disease in the future.
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Liu F, Luo Z, Li Y, Zheng X, Zhang C, Qian H. Revisiting physical distancing threshold in indoor environment using infection-risk-based modeling. ENVIRONMENT INTERNATIONAL 2021; 153:106542. [PMID: 33819720 PMCID: PMC8016632 DOI: 10.1016/j.envint.2021.106542] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/20/2021] [Accepted: 03/22/2021] [Indexed: 05/09/2023]
Abstract
Physical distancing has been an important policy to mitigate the spread of the novel coronavirus disease 2019 (COVID-19) in public settings. However, the current 1-2 m physical distancing rule is based on the physics of droplet transport and could not directly translate into infection risk. We therefore revisit the 2-m physical distancing rule by developing an infection-risk-based model for human speaking. The key modeling framework components include viral load, droplets dispersion and evaporation, deposition efficiency, viral dose-response rate and infection risk. The results suggest that the one-size-fits-all 2-m physical distancing rule derived from the pure droplet-physics-based model is not applicable under some realistic indoor settings, and may rather increase transmission probability of diseases. Especially, in thermally stratified environments, the infection risk could exhibit multiple peaks for a long distance beyond 2 m. With Sobol's sensitivity analysis, most variance of the risk is found to be significantly attributable to the variability in temperature gradient, exposure time and breathing height difference. Our study suggests there is no such magic 2 m physical distancing rule for all environments, but it needs to be used alongside other strategies, such as using face cover, reducing exposure time, and controlling the thermal stratification of indoor environment.
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Affiliation(s)
- Fan Liu
- School of Energy and Environment, Southeast University, Nanjing, China; School of the Built Environment, University of Reading, Reading, United Kingdom
| | - Zhiwen Luo
- School of the Built Environment, University of Reading, Reading, United Kingdom.
| | - Yuguo Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Xiaohong Zheng
- School of Energy and Environment, Southeast University, Nanjing, China; Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology, School of Energy and Environment, Southeast University, Nanjing, China
| | - Chongyang Zhang
- School of Energy and Environment, Southeast University, Nanjing, China; Shanghai Research Institute of Building Sciences (Group) Co., Ltd., Shanghai, China
| | - Hua Qian
- School of Energy and Environment, Southeast University, Nanjing, China.
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Raines KS, Doniach S, Bhanot G. The transmission of SARS-CoV-2 is likely comodulated by temperature and by relative humidity. PLoS One 2021; 16:e0255212. [PMID: 34324570 PMCID: PMC8321224 DOI: 10.1371/journal.pone.0255212] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 07/12/2021] [Indexed: 01/08/2023] Open
Abstract
Inferring the impact of climate upon the transmission of SARS-CoV-2 has been confounded by variability in testing, unknown disease introduction rates, and changing weather. Here we present a data model that accounts for dynamic testing rates and variations in disease introduction rates. We apply this model to data from Colombia, whose varied and seasonless climate, central port of entry, and swift, centralized response to the COVID-19 pandemic present an opportune environment for assessing the impact of climate factors on the spread of COVID-19. We observe strong attenuation of transmission in climates with sustained daily temperatures above 30 degrees Celsius and simultaneous mean relative humidity below 78%, with outbreaks occurring at high humidity even where the temperature is high. We hypothesize that temperature and relative humidity comodulate the infectivity of SARS-CoV-2 within respiratory droplets.
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Affiliation(s)
| | - Sebastian Doniach
- Applied Physics, Stanford University, Stanford, CA, United States of America
| | - Gyan Bhanot
- Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America
- Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, United States of America
- School of Medicine, University of California San Diego, La Jolla, CA, United States of America
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12
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Abstract
AbstractMist is generated by ultrasonic cavitation of water (Fisher Biograde, pH 5.5–6.5) at room temperature (20–25 °C) in open air with nearly constant temperature (22–25 °C) but varying relative humidity (RH; 24–52%) over the course of many months. Water droplets in the mist are initially about 7 μm in diameter at about 50% RH. They are collected, and the concentration of hydrogen peroxide (H2O2) is measured using commercial peroxide test strips and by bromothymol blue oxidation. The quantification method is based on the Fenton chemistry of dye degradation to determine the oxidation capacity of water samples that have been treated by ultrasonication. It is found that the hydrogen peroxide concentration varies nearly linearly with RH over the range studied, reaching a low of 2 parts per million (ppm) at 24% RH and a high of 6 ppm at 52% RH. Some possible public health implications concerning the transmission of respiratory viral infections are suggested for this threefold change in H2O2 concentration with RH.
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Löhner R, Antil H, Srinivasan A, Idelsohn S, Oñate E. High-Fidelity Simulation of Pathogen Propagation, Transmission and Mitigation in the Built Environment. ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING : STATE OF THE ART REVIEWS 2021; 28:4237-4262. [PMID: 34248352 PMCID: PMC8256653 DOI: 10.1007/s11831-021-09606-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/08/2021] [Indexed: 05/31/2023]
Abstract
An overview of high-fidelity modeling of pathogen propagation, transmission and mitigation in the built environment is given. In order to derive the required physical and numerical models, the current understanding of pathogen, and in particular virus transmission and mitigation is summarized. The ordinary and partial differential equations that describe the flow, the particles and possibly the UV radiation loads in rooms or HVAC ducts are presented, as well as proper numerical methods to solve them in an expedient way. Thereafter, the motion of pedestrians, as well as proper ways to couple computational fluid dynamics and computational crowd dynamics to enable high-fidelity pathogen transmission and infection simulations is treated. The present review shows that high-fidelity simulations of pathogen propagation, transmission and mitigation in the built environment have reached a high degree of sophistication, offering a quantum leap in accuracy from simpler probabilistic models. This is particularly the case when considering the propagation of pathogens via aerosols in the presence of moving pedestrians.
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Affiliation(s)
- Rainald Löhner
- Center for Computational Fluid Dynamics, College of Science, George Mason University, Fairfax, VA 22030-4444 USA
| | - Harbir Antil
- Center for Mathematics and Artificial Intelligence, College of Science, George Mason University, Fairfax, VA 22030-4444 USA
| | - Ashok Srinivasan
- Department of Computer Science, University of West Florida, Pensacola, FL 32514 USA
| | - Sergio Idelsohn
- Catalan Institution for Research and Advanced Studies, ICREA, Barcelona, Spain
- International Center for Numerical Methods in Engineering, CIMNE, Barcelona, Spain
| | - Eugenio Oñate
- International Center for Numerical Methods in Engineering, CIMNE, Barcelona, Spain
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14
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Saadi S, Kallala O, Fodha I, Jerbi A, BenHamida-Rebai M, Ben Hadj Fredj M, Ben Hamouda H, Mathlouthi J, Khlifa M, Boussofara R, Boussetta K, Abroug S, Trabelsi A. Correlation between Children Respiratory Virus Infections and Climate Factors. J PEDIAT INF DIS-GER 2021. [DOI: 10.1055/s-0040-1722569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Abstract
Objective Respiratory viruses are the most important cause of lower respiratory tract infections (LRTI) in children. Meteorological factors can influence viral outbreaks. The objective of this study was to determine the association between climate variables and respiratory virus detection.
Methods Multicenter prospective 1-year surveillance was conducted among children hospitalized for LRTI in Tunisia. Nasopharyngeal aspirates were tested by direct immunofluorescence assay (DIFA) for the detection of respiratory syncytial virus (RSV); adenovirus (AdV); influenza virus (IFV) A and B; and parainfluenza virus 1, 2, and 3 (PIV1/2/3). Samples were further analyzed by reverse-transcription polymerase chain reaction for the detection of human metapneumovirus (hMPV). Monthly meteorological data were determined by consulting the National Institute of Meteorology and the World Weather Online Meteorological Company websites. Pearson's correlation tests were used to determine the statistical association between the detection of respiratory viruses and climatic characteristics.
Results Among 572 patients, 243 (42.5%) were positive for at least one virus. The most frequently detected viruses by DIFA were RSV (30.0%), followed by IFVA (3.8%), IFVB (3.5%), PIV (0.9%), and AdV (0.9%). HMPV was detected in 13 RSV-negative samples (3.3%). Dual infections were detected in seven cases (1.2%). Monthly global respiratory viruses and RSV detections correlated significantly with temperature, rainfall, cloud cover, wind speed, wind temperature, and duration of sunshine. Monthly IFV detection significantly correlated with rainfall, wind speed, wind temperature, and duration of sunshine. HMPV detection significantly correlated with temperature and wind temperature.
Conclusion Respiratory viral outbreaks are clearly related to meteorological factors in Tunisia.
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Affiliation(s)
- Souhir Saadi
- Research Laboratory for “Epidemiology and Immunogenetics of Viral Infections,” Sahloul University Hospital, University of Sousse, Sousse, Tunisia
- Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
| | - Ouafa Kallala
- Research Laboratory for “Epidemiology and Immunogenetics of Viral Infections,” Sahloul University Hospital, University of Sousse, Sousse, Tunisia
- Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
| | - Imene Fodha
- Research Laboratory for “Epidemiology and Immunogenetics of Viral Infections,” Sahloul University Hospital, University of Sousse, Sousse, Tunisia
- Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
| | - Amira Jerbi
- Research Laboratory for “Epidemiology and Immunogenetics of Viral Infections,” Sahloul University Hospital, University of Sousse, Sousse, Tunisia
- Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
| | - Meriem BenHamida-Rebai
- Research Laboratory for “Epidemiology and Immunogenetics of Viral Infections,” Sahloul University Hospital, University of Sousse, Sousse, Tunisia
- Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
| | - Mouna Ben Hadj Fredj
- Research Laboratory for “Epidemiology and Immunogenetics of Viral Infections,” Sahloul University Hospital, University of Sousse, Sousse, Tunisia
- Faculty of Sciences and Techniques, University of Kairouan, Kairouan, Tunisia
| | | | - Jihen Mathlouthi
- Neonatology Ward, Farhat Hached University Hospital, Sousse, Tunisia
| | - Monia Khlifa
- Pediatric Ward, Regional Hospital of Msaken, Sousse, Tunisia
| | | | | | - Saoussen Abroug
- Pediatric Ward, Sahloul University Hospital, Sousse, Tunisia
| | - Abdelhalim Trabelsi
- Research Laboratory for “Epidemiology and Immunogenetics of Viral Infections,” Sahloul University Hospital, University of Sousse, Sousse, Tunisia
- Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
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15
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Raines KS, Doniach S, Bhanot G. The transmission of SARS-CoV-2 is likely comodulated by temperature and by relative humidity. PLoS One 2021. [PMID: 34324570 DOI: 10.1101/2020.05.23.20111278] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023] Open
Abstract
Inferring the impact of climate upon the transmission of SARS-CoV-2 has been confounded by variability in testing, unknown disease introduction rates, and changing weather. Here we present a data model that accounts for dynamic testing rates and variations in disease introduction rates. We apply this model to data from Colombia, whose varied and seasonless climate, central port of entry, and swift, centralized response to the COVID-19 pandemic present an opportune environment for assessing the impact of climate factors on the spread of COVID-19. We observe strong attenuation of transmission in climates with sustained daily temperatures above 30 degrees Celsius and simultaneous mean relative humidity below 78%, with outbreaks occurring at high humidity even where the temperature is high. We hypothesize that temperature and relative humidity comodulate the infectivity of SARS-CoV-2 within respiratory droplets.
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Affiliation(s)
| | - Sebastian Doniach
- Applied Physics, Stanford University, Stanford, CA, United States of America
| | - Gyan Bhanot
- Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America
- Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, United States of America
- School of Medicine, University of California San Diego, La Jolla, CA, United States of America
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16
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Jarvis MC. Aerosol Transmission of SARS-CoV-2: Physical Principles and Implications. Front Public Health 2020; 8:590041. [PMID: 33330334 PMCID: PMC7719704 DOI: 10.3389/fpubh.2020.590041] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/30/2020] [Indexed: 12/23/2022] Open
Abstract
Evidence has emerged that SARS-CoV-2, the coronavirus that causes COVID-19, can be transmitted airborne in aerosol particles as well as in larger droplets or by surface deposits. This minireview outlines the underlying aerosol science, making links to aerosol research in other disciplines. SARS-CoV-2 is emitted in aerosol form during normal breathing by both asymptomatic and symptomatic people, remaining viable with a half-life of up to about an hour during which air movement can carry it considerable distances, although it simultaneously disperses. The proportion of the droplet size distribution within the aerosol range depends on the sites of origin within the respiratory tract and on whether the distribution is presented on a number or volume basis. Evaporation and fragmentation reduce the size of the droplets, whereas coalescence increases the mean droplet size. Aerosol particles containing SARS-CoV-2 can also coalesce with pollution particulates, and infection rates correlate with pollution. The operation of ventilation systems in public buildings and transportation can create infection hazards via aerosols, but provides opportunities for reducing the risk of transmission in ways as simple as switching from recirculated to outside air. There are also opportunities to inactivate SARS-CoV-2 in aerosol form with sunlight or UV lamps. The efficiency of masks for blocking aerosol transmission depends strongly on how well they fit. Research areas that urgently need further experimentation include the basis for variation in droplet size distribution and viral load, including droplets emitted by "superspreader" individuals; the evolution of droplet sizes after emission, their interaction with pollutant aerosols and their dispersal by turbulence, which gives a different basis for social distancing.
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17
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Löhner R, Antil H, Idelsohn S, Oñate E. Detailed simulation of viral propagation in the built environment. COMPUTATIONAL MECHANICS 2020; 66:1093-1107. [PMID: 32836601 PMCID: PMC7403197 DOI: 10.1007/s00466-020-01881-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 06/29/2020] [Indexed: 05/20/2023]
Abstract
A summary is given of the mechanical characteristics of virus contaminants and the transmission via droplets and aerosols. The ordinary and partial differential equations describing the physics of these processes with high fidelity are presented, as well as appropriate numerical schemes to solve them. Several examples taken from recent evaluations of the built environment are shown, as well as the optimal placement of sensors.
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Affiliation(s)
- Rainald Löhner
- Center for Computational Fluid Dynamics, College of Science, George Mason University, Fairfax, VA 22030-4444 USA
| | - Harbir Antil
- Center for Mathematics and Artificial Intelligence, College of Science, George Mason University, Fairfax, VA 22030-4444 USA
| | - Sergio Idelsohn
- ICREA, Catalan Institution for Research and Advanced Studies, Barcelona, Spain
- CIMNE, International Center for Numerical Methods in Engineering, Barcelona, Spain
| | - Eugenio Oñate
- CIMNE, International Center for Numerical Methods in Engineering, Barcelona, Spain
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18
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Kormuth KA, Lin K, Prussin AJ, Vejerano EP, Tiwari AJ, Cox SS, Myerburg MM, Lakdawala SS, Marr LC. Influenza Virus Infectivity Is Retained in Aerosols and Droplets Independent of Relative Humidity. J Infect Dis 2019; 218:739-747. [PMID: 29878137 PMCID: PMC6057527 DOI: 10.1093/infdis/jiy221] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 04/17/2018] [Indexed: 12/18/2022] Open
Abstract
Pandemic and seasonal influenza viruses can be transmitted through aerosols and droplets, in which viruses must remain stable and infectious across a wide range of environmental conditions. Using humidity-controlled chambers, we studied the impact of relative humidity on the stability of 2009 pandemic influenza A(H1N1) virus in suspended aerosols and stationary droplets. Contrary to the prevailing paradigm that humidity modulates the stability of respiratory viruses in aerosols, we found that viruses supplemented with material from the apical surface of differentiated primary human airway epithelial cells remained equally infectious for 1 hour at all relative humidities tested. This sustained infectivity was observed in both fine aerosols and stationary droplets. Our data suggest, for the first time, that influenza viruses remain highly stable and infectious in aerosols across a wide range of relative humidities. These results have significant implications for understanding the mechanisms of transmission of influenza and its seasonality.
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Affiliation(s)
- Karen A Kormuth
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pennsylvania
| | - Kaisen Lin
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg
| | - Aaron J Prussin
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg
| | - Eric P Vejerano
- Department of Environmental Health Sciences, University of South Carolina, Columbia
| | - Andrea J Tiwari
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg
| | - Steve S Cox
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg
| | - Michael M Myerburg
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, Pennsylvania
| | - Seema S Lakdawala
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pennsylvania
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg
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19
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Marr LC, Tang JW, Van Mullekom J, Lakdawala SS. Mechanistic insights into the effect of humidity on airborne influenza virus survival, transmission and incidence. J R Soc Interface 2019. [PMID: 30958176 DOI: 10.6084/m9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023] Open
Abstract
Influenza incidence and seasonality, along with virus survival and transmission, appear to depend at least partly on humidity, and recent studies have suggested that absolute humidity (AH) is more important than relative humidity (RH) in modulating observed patterns. In this perspective article, we re-evaluate studies of influenza virus survival in aerosols, transmission in animal models and influenza incidence to show that the combination of temperature and RH is equally valid as AH as a predictor. Collinearity must be considered, as higher levels of AH are only possible at higher temperatures, where it is well established that virus decay is more rapid. In studies of incidence that employ meteorological data, outdoor AH may be serving as a proxy for indoor RH in temperate regions during the wintertime heating season. Finally, we present a mechanistic explanation based on droplet evaporation and its impact on droplet physics and chemistry for why RH is more likely than AH to modulate virus survival and transmission.
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Affiliation(s)
- Linsey C Marr
- 1 Civil and Environmental Engineering, Virginia Tech , Blacksburg, VA 24061 , USA
| | - Julian W Tang
- 2 Clinical Microbiology, University Hospitals Leicester NHS Trust , Leicester , UK
- 3 Infection, Immunity and Inflammation, University of Leicester , Leicester , UK
| | | | - Seema S Lakdawala
- 5 Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine , Pittsburgh, PA 15219 , USA
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20
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Marr LC, Tang JW, Van Mullekom J, Lakdawala SS. Mechanistic insights into the effect of humidity on airborne influenza virus survival, transmission and incidence. J R Soc Interface 2019; 16:20180298. [PMID: 30958176 PMCID: PMC6364647 DOI: 10.1098/rsif.2018.0298] [Citation(s) in RCA: 213] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 12/20/2018] [Indexed: 12/27/2022] Open
Abstract
Influenza incidence and seasonality, along with virus survival and transmission, appear to depend at least partly on humidity, and recent studies have suggested that absolute humidity (AH) is more important than relative humidity (RH) in modulating observed patterns. In this perspective article, we re-evaluate studies of influenza virus survival in aerosols, transmission in animal models and influenza incidence to show that the combination of temperature and RH is equally valid as AH as a predictor. Collinearity must be considered, as higher levels of AH are only possible at higher temperatures, where it is well established that virus decay is more rapid. In studies of incidence that employ meteorological data, outdoor AH may be serving as a proxy for indoor RH in temperate regions during the wintertime heating season. Finally, we present a mechanistic explanation based on droplet evaporation and its impact on droplet physics and chemistry for why RH is more likely than AH to modulate virus survival and transmission.
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Affiliation(s)
- Linsey C. Marr
- Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Julian W. Tang
- Clinical Microbiology, University Hospitals Leicester NHS Trust, Leicester, UK
- Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | | | - Seema S. Lakdawala
- Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
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21
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Smith AP, Moquin DJ, Bernhauerova V, Smith AM. Influenza Virus Infection Model With Density Dependence Supports Biphasic Viral Decay. Front Microbiol 2018; 9:1554. [PMID: 30042759 PMCID: PMC6048257 DOI: 10.3389/fmicb.2018.01554] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/22/2018] [Indexed: 01/13/2023] Open
Abstract
Mathematical models that describe infection kinetics help elucidate the time scales, effectiveness, and mechanisms underlying viral growth and infection resolution. For influenza A virus (IAV) infections, the standard viral kinetic model has been used to investigate the effect of different IAV proteins, immune mechanisms, antiviral actions, and bacterial coinfection, among others. We sought to further define the kinetics of IAV infections by infecting mice with influenza A/PR8 and measuring viral loads with high frequency and precision over the course of infection. The data highlighted dynamics that were not previously noted, including viral titers that remain elevated for several days during mid-infection and a sharp 4–5 log10 decline in virus within 1 day as the infection resolves. The standard viral kinetic model, which has been widely used within the field, could not capture these dynamics. Thus, we developed a new model that could simultaneously quantify the different phases of viral growth and decay with high accuracy. The model suggests that the slow and fast phases of virus decay are due to the infected cell clearance rate changing as the density of infected cells changes. To characterize this model, we fit the model to the viral load data, examined the parameter behavior, and connected the results and parameters to linear regression estimates. The resulting parameters and model dynamics revealed that the rate of viral clearance during resolution occurs 25 times faster than the clearance during mid-infection and that small decreases to this rate can significantly prolong the infection. This likely reflects the high efficiency of the adaptive immune response. The new model provides a well-characterized representation of IAV infection dynamics, is useful for analyzing and interpreting viral load dynamics in the absence of immunological data, and gives further insight into the regulation of viral control.
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Affiliation(s)
- Amanda P Smith
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - David J Moquin
- Department of Internal Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
| | | | - Amber M Smith
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States
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22
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Handel A, Rohani P. Crossing the scale from within-host infection dynamics to between-host transmission fitness: a discussion of current assumptions and knowledge. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0302. [PMID: 26150668 DOI: 10.1098/rstb.2014.0302] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The progression of an infection within a host determines the ability of a pathogen to transmit to new hosts and to maintain itself in the population. While the general connection between the infection dynamics within a host and the population-level transmission dynamics of pathogens is widely acknowledged, a comprehensive and quantitative understanding that would allow full integration of the two scales is still lacking. Here, we provide a brief discussion of both models and data that have attempted to provide quantitative mappings from within-host infection dynamics to transmission fitness. We present a conceptual framework and provide examples of studies that have taken first steps towards development of a quantitative framework that scales from within-host infections to population-level fitness of different pathogens. We hope to illustrate some general themes, summarize some of the recent advances and-maybe most importantly-discuss gaps in our ability to bridge these scales, and to stimulate future research on this important topic.
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Affiliation(s)
- Andreas Handel
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, GA 30602, USA
| | - Pejman Rohani
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
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23
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Halloran SK, Wexler AS, Ristenpart WD. Turbulent dispersion via fan-generated flows. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2014; 26:055114. [PMID: 24932096 PMCID: PMC4039734 DOI: 10.1063/1.4879256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 05/07/2014] [Indexed: 06/03/2023]
Abstract
Turbulent dispersion of passive scalar quantities has been extensively studied in wind tunnel settings, where the flow is carefully conditioned using flow straighteners and grids. Much less is known about turbulent dispersion in the "unconditioned" flows generated by fans that are ubiquitous in indoor environments, despite the importance of these flows to pathogen and contaminant transport. Here, we demonstrate that a point source of scalars released into an airflow generated by an axial fan yields a plume whose width is invariant with respect to the fan speed. The results point toward a useful simplification in modeling of disease and pollution spread via fan-generated flows.
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Affiliation(s)
- Siobhan K Halloran
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California 95616, USA
| | - Anthony S Wexler
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, California 95616, USA; Air Quality Research Center, University of California Davis, Davis, California 95616, USA; Department of Civil and Environmental Engineering, University of California Davis, Davis, California 95616, USA; and Department of Land, Air and Water Resources, University of California Davis, Davis, California 95616, USA
| | - William D Ristenpart
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California 95616, USA
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24
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Handel A, Akin V, Pilyugin SS, Zarnitsyna V, Antia R. How sticky should a virus be? The impact of virus binding and release on transmission fitness using influenza as an example. J R Soc Interface 2014; 11:20131083. [PMID: 24430126 DOI: 10.1098/rsif.2013.1083] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Budding viruses face a trade-off: virions need to efficiently attach to and enter uninfected cells while newly generated virions need to efficiently detach from infected cells. The right balance between attachment and detachment-the right amount of stickiness-is needed for maximum fitness. Here, we design and analyse a mathematical model to study in detail the impact of attachment and detachment rates on virus fitness. We apply our model to influenza, where stickiness is determined by a balance of the haemagglutinin (HA) and neuraminidase (NA) proteins. We investigate how drugs, the adaptive immune response and vaccines impact influenza stickiness and fitness. Our model suggests that the location in the 'stickiness landscape' of the virus determines how well interventions such as drugs or vaccines are expected to work. We discuss why hypothetical NA enhancer drugs might occasionally perform better than the currently available NA inhibitors in reducing virus fitness. We show that an increased antibody or T-cell-mediated immune response leads to maximum fitness at higher stickiness. We further show that antibody-based vaccines targeting mainly HA or NA, which leads to a shift in stickiness, might reduce virus fitness above what can be achieved by the direct immunological action of the vaccine. Overall, our findings provide potentially useful conceptual insights for future vaccine and drug development and can be applied to other budding viruses beyond influenza.
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Affiliation(s)
- Andreas Handel
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, , Athens, GA 30602, USA
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25
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Lackemeyer MG, Kok-Mercado FD, Wada J, Bollinger L, Kindrachuk J, Wahl-Jensen V, Kuhn JH, Jahrling PB. ABSL-4 aerobiology biosafety and technology at the NIH/NIAID integrated research facility at Fort Detrick. Viruses 2014; 6:137-50. [PMID: 24402304 PMCID: PMC3917435 DOI: 10.3390/v6010137] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/18/2013] [Accepted: 12/20/2013] [Indexed: 12/20/2022] Open
Abstract
The overall threat of a viral pathogen to human populations is largely determined by the modus operandi and velocity of the pathogen that is transmitted among humans. Microorganisms that can spread by aerosol are considered a more challenging enemy than those that require direct body-to-body contact for transmission, due to the potential for infection of numerous people rather than a single individual. Additionally, disease containment is much more difficult to achieve for aerosolized viral pathogens than for pathogens that spread solely via direct person-to-person contact. Thus, aerobiology has become an increasingly necessary component for studying viral pathogens that are naturally or intentionally transmitted by aerosol. The goal of studying aerosol viral pathogens is to improve public health preparedness and medical countermeasure development. Here, we provide a brief overview of the animal biosafety level 4 Aerobiology Core at the NIH/NIAID Integrated Research Facility at Fort Detrick, Maryland, USA.
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Affiliation(s)
- Matthew G Lackemeyer
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
| | - Fabian de Kok-Mercado
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
| | - Jiro Wada
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
| | - Laura Bollinger
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
| | - Jason Kindrachuk
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
| | - Victoria Wahl-Jensen
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
| | - Peter B Jahrling
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA.
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26
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Handel A, Brown J, Stallknecht D, Rohani P. A multi-scale analysis of influenza A virus fitness trade-offs due to temperature-dependent virus persistence. PLoS Comput Biol 2013; 9:e1002989. [PMID: 23555223 PMCID: PMC3605121 DOI: 10.1371/journal.pcbi.1002989] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 02/04/2013] [Indexed: 01/13/2023] Open
Abstract
Successful replication within an infected host and successful transmission between hosts are key to the continued spread of most pathogens. Competing selection pressures exerted at these different scales can lead to evolutionary trade-offs between the determinants of fitness within and between hosts. Here, we examine such a trade-off in the context of influenza A viruses and the differential pressures exerted by temperature-dependent virus persistence. For a panel of avian influenza A virus strains, we find evidence for a trade-off between the persistence at high versus low temperatures. Combining a within-host model of influenza infection dynamics with a between-host transmission model, we study how such a trade-off affects virus fitness on the host population level. We show that conclusions regarding overall fitness are affected by the type of link assumed between the within- and between-host levels and the main route of transmission (direct or environmental). The relative importance of virulence and immune response mediated virus clearance are also found to influence the fitness impacts of virus persistence at low versus high temperatures. Based on our results, we predict that if transmission occurs mainly directly and scales linearly with virus load, and virulence or immune responses are negligible, the evolutionary pressure for influenza viruses to evolve toward good persistence at high within-host temperatures dominates. For all other scenarios, influenza viruses with good environmental persistence at low temperatures seem to be favored. It has recently been suggested that for avian influenza viruses, prolonged persistence in the environment plays an important role in the transmission between birds. In such situations, influenza virus strains may face a trade-off: they need to persist well in the environment at low temperatures, but they also need to do well inside an infected bird at higher temperatures. Here, we analyze how potential trade-offs on these two scales interact to determine overall fitness of the virus. We find that the link between infection dynamics within a host and virus shedding and transmission is crucial in determining the relative advantage of good low-temperature versus high-temperature persistence. We also find that the role of virus-induced mortality, the immune response and the route of transmission affect the balance between optimal low-temperature and high-temperature persistence.
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Affiliation(s)
- Andreas Handel
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia, United States of America.
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