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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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202
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Ai Z, Mak CM, Gao N, Niu J. Tracer gas is a suitable surrogate of exhaled droplet nuclei for studying airborne transmission in the built environment. BUILDING SIMULATION 2020; 13:489-496. [PMID: 32211124 PMCID: PMC7090680 DOI: 10.1007/s12273-020-0614-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/31/2019] [Accepted: 01/15/2020] [Indexed: 05/04/2023]
Affiliation(s)
- Zhengtao Ai
- Department of Building Environment and Energy, College of Civil Engineering, Hunan University, Changsha, China
| | - Cheuk Ming Mak
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Naiping Gao
- School of Mechanical Engineering, Tongji University, Shanghai, China
| | - Jianlei Niu
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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203
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MacIntyre CR, Das A, Chen X, Silva CD, Doolan C. Evidence of Long-Distance Aerial Convection of Variola Virus and Implications for Disease Control. Viruses 2019; 12:E33. [PMID: 31892158 PMCID: PMC7019718 DOI: 10.3390/v12010033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/13/2019] [Accepted: 12/25/2019] [Indexed: 02/06/2023] Open
Abstract
Two distinct phenomena of airborne transmission of variola virus (smallpox) were described in the pre-eradication era-direct respiratory transmission, and a unique phenomenon of transmission over greater distances, referred to as "aerial convection". We conducted an analysis of data obtained from a systematic review following the PRISMA criteria, on the long-distance transmission of smallpox. Of 8179 studies screened, 22 studies of 17 outbreaks were identified-12 had conclusive evidence of aerial convection and five had partially conclusive evidence. Aerial convection was first documented in 1881 in England, when smallpox incidence had waned substantially following mass vaccination, making unusual transmissions noticeable. National policy at the time stipulated spatial separation of smallpox hospitals from other buildings and communities. The evidence supports the transmission of smallpox through aerial convection at distances ranging from 0.5 to 1 mile, and one instance of 15 km related to bioweapons testing. Other explanations are also possible, such as missed chains of transmission, fomites or secondary aerosolization from contaminated material such as bedding. The window of observation of aerial convection was within the 100 years prior to eradication. Aerial convection appears unique to the variola virus and is not considered in current hospital infection control protocols. Understanding potential aerial convection of variola should be an important consideration in planning for smallpox treatment facilities and protecting potential contacts and surrounding communities.
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Affiliation(s)
- Chandini Raina MacIntyre
- Biosecurity Program, The Kirby Institute, UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia; (C.R.M.); (A.D.)
- College of Health Solutions, Arizona State University, Phoenix, AZ 85004, USA
- College of Public Service and Community Solutions, Arizona State University, Phoenix, AZ 85004, USA
| | - Arpita Das
- Biosecurity Program, The Kirby Institute, UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia; (C.R.M.); (A.D.)
| | - Xin Chen
- Biosecurity Program, The Kirby Institute, UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia; (C.R.M.); (A.D.)
| | - Charitha De Silva
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052, Australia; (C.D.S.); (C.D.)
| | - Con Doolan
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052, Australia; (C.D.S.); (C.D.)
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204
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Stec J, Lenart-Boroń A. Assessment of microbiological aerosol concentration in selected healthcare facilities in southern Poland. Cent Eur J Public Health 2019; 27:239-244. [PMID: 31580561 DOI: 10.21101/cejph.a5681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/05/2019] [Indexed: 11/15/2022]
Abstract
OBJECTIVES This study was aimed to assess the concentration of microbial aerosol and species composition of airborne staphylococci in 10 healthcare facilities in southern Poland including primary healthcare units and hospital wards; and to assess whether the selected components of microbial aerosol pose a threat of severe infections to either patients or the personnel. METHODS The study was conducted at monthly intervals over a period of one year. Air samples were collected by MAS-100 sampler. The number of mesophilic bacteria, mould fungi, actinomycetes and staphylococci was determined on general and selective media. The species identification of staphylococci was conducted using API tests for strains that were pre-selected based on macroscopic and microscopic observations. RESULTS A total number of 1,584 samples were collected during the sampling period. The numbers of airborne microorganisms varied between the examined premises and between the seasons of the year. The observed differences were statistically significant with one exception for actinomycetes and their differences between the examined premises. The concentrations of mesophilic bacteria varied from 5 to 297 CFU/m3 of air, for Staphylococcus the values ranged from 1 to 96 CFU/m3, for fungi - from 1 to 100 CFU/m3, and the number of actinomycetes ranged from 7 to 321 CFU/m3. Ten species of coagulase-negative staphylococci (CoNS) were identified among 55 isolates with S. saprophyticus and S. warneri being the most frequently detected (n = 14 and 13, respectively). S. haemolyticus, which is one of the most common causal agents of nosocomial infections was observed in four facilities (n = 5). CONCLUSIONS The microbial concentrations varied both between the seasons of the year and between the examined facilities. The highest bioaerosol concentrations were observed in most crowded premises. The identified species of staphylococci, although not typically associated with human infections, are common causal agents of nosocomial infections and infections in immunocompromised people.
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Affiliation(s)
- Joanna Stec
- Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, Krakow, Poland
| | - Anna Lenart-Boroń
- Department of Microbiology, Faculty of Agriculture and Economics, University of Agriculture in Krakow, Krakow, Poland
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205
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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: 123] [Impact Index Per Article: 24.6] [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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206
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Aerosol Detection and Transmission of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV): What Is the Evidence, and What Are the Knowledge Gaps? Viruses 2019; 11:v11080712. [PMID: 31382628 PMCID: PMC6723176 DOI: 10.3390/v11080712] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 12/18/2022] Open
Abstract
In human and veterinary medicine, there have been multiple reports of pathogens being airborne under experimental and field conditions, highlighting the importance of this transmission route. These studies shed light on different aspects related to airborne transmission such as the capability of pathogens becoming airborne, the ability of pathogens to remain infectious while airborne, the role played by environmental conditions in pathogen dissemination, and pathogen strain as an interfering factor in airborne transmission. Data showing that airborne pathogens originating from an infectious individual or population can infect susceptible hosts are scarce, especially under field conditions. Furthermore, even though disease outbreak investigations have generated important information identifying potential ports of entry of pathogens into populations, these investigations do not necessarily yield clear answers on mechanisms by which pathogens have been introduced into populations. In swine, the aerosol transmission route gained popularity during the late 1990’s as suspicions of airborne transmission of porcine reproductive and respiratory syndrome virus (PRRSV) were growing. Several studies were conducted within the last 15 years contributing to the understanding of this transmission route; however, questions still remain. This paper reviews the current knowledge and identifies knowledge gaps related to PRRSV airborne transmission.
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207
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Abstract
When sawing bone for medical or medico-legal procedures, fine, airborne dust is produced (aerosols) that can pose a health hazard when inhaled. The aim of this study was to determine the influence of saw blade frequency and contact load, bone condition, test environment, and saw blade type, on the production of aerosol particles. A custom test setup was designed, manufactured and used in 8 bone sawing experiments, using a particle counter to determine the production of aerosol particles while varying the 5 chosen parameters. The number of counted particles was highest with higher saw blade frequencies, lower saw blade contact loads, in dry completely skeletonized bone compared to fresh bone, and using an electrical oscillating saw compared to hand-sawing. Under all conditions, the high amount of aerosol counted posed potential health risks. The ventilation system that we tested was adequate in removing the produced particles, but these high-tech systems are not always available in developing countries or emergency situations. The production of aerosols can be reduced by optimizing the sawing parameters. However, even the lowest number of aerosol particles counted during the current study was high enough to cause potential health risks to practitioners. Safety precautions should be taken, such as external ventilation, proper breathing gear, and adequate protocols, to truly minimize the risk in all bone sawing scenarios.
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Affiliation(s)
- Jip M. E. Pluim
- Department of Forensic Anthropology, Netherlands Forensic Institute, Laan van Ypenburg 6, 2497GB The Hague, Netherlands
- Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, F-0-200, Mekelweg 2, 2628CD Delft, The Netherlands
| | - Arjo J. Loeve
- Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, F-0-200, Mekelweg 2, 2628CD Delft, The Netherlands
- Co van Ledden-Hulsebosch Centrum, Science Park Building 904, 1098XH Amsterdam, The Netherlands
| | - Reza R. R. Gerretsen
- Department of Forensic Anthropology, Netherlands Forensic Institute, Laan van Ypenburg 6, 2497GB The Hague, Netherlands
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Stockwell RE, Ballard EL, O'Rourke P, Knibbs LD, Morawska L, Bell SC. Indoor hospital air and the impact of ventilation on bioaerosols: a systematic review. J Hosp Infect 2019; 103:175-184. [PMID: 31279762 DOI: 10.1016/j.jhin.2019.06.016] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/28/2019] [Indexed: 10/26/2022]
Abstract
Healthcare-acquired infections (HAIs) continue to persist in hospitals, despite the use of increasingly strict infection-control precautions. Opportunistic airborne transmission of potentially pathogenic bioaerosols may be one possible reason for this persistence. Therefore, this study aimed to systematically review the concentrations and compositions of indoor bioaerosols in different areas within hospitals and the effects of different ventilation systems. Electronic databases (Medline and Web of Science) were searched to identify articles of interest. The search was restricted to articles published from 2000 to 2017 in English. Aggregate data was used to examine the differences in mean colony forming units per cubic metre (cfu/m3) between different hospital areas and ventilation types. A total of 36 journal articles met the eligibility criteria. The mean total bioaerosol concentrations in the different areas of the hospitals were highest in the inpatient facilities (77 cfu/m3, 95% confidence interval (CI): 55-108) compared with the restricted (13cfu/m3, 95% CI: 10-15) and public areas (14 cfu/m3, 95% CI: 10-19). Hospital areas with natural ventilation had the highest total bioaerosol concentrations (201 cfu/m3, 95% CI: 135-300) compared with areas using conventional mechanical ventilation systems (20 cfu/m3, 95% CI: 16-24). Hospital areas using sophisticated mechanical ventilation systems (such as increased air changes per hour, directional flow and filtration systems) had the lowest total bioaerosol concentrations (9 cfu/m3, 95% CI: 7-13). Operating sophisticated mechanical ventilation systems in hospitals contributes to improved indoor air quality within hospitals, which assists in reducing the risk of airborne transmission of HAIs.
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Affiliation(s)
- R E Stockwell
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia; Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - E L Ballard
- Statistical Support Group, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - P O'Rourke
- Statistical Support Group, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - L D Knibbs
- School of Public Health, The University of Queensland, Herston, Queensland, Australia
| | - L Morawska
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - S C Bell
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia; Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia; Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, Queensland, Australia.
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209
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Qoreishi M, Abbasian M, Safdari F. Sterile Parts of Operating Gown during Lower Limb Joint Replacement Surgery. THE ARCHIVES OF BONE AND JOINT SURGERY 2019; 7:354-359. [PMID: 31448313 PMCID: PMC6686066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/10/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND The prevention of surgical site infection is one of the most concerning issues in operating rooms. Surgical gowns are worn as one of the intraoperative strategies for infection prevention. The present study investigated whether the gowns remained sterile during the surgical procedure. Furthermore, this study examined which parts of the surgical gown were more prone to contamination. METHODS The sterility of the gowns was investigated during eight total joint arthroplasties all of which were performed by four surgeons. The samples were taken from the arms and frontal part of the sterile gowns pre- and postoperatively. In the anterior surface of the gown, the sampling was initiated at a strip with 50 cm height from the ground followed by the strips with 15 cm distances from caudal to cephalad. Furthermore, the frontal part of the gown was divided into three parts in relation to the operating room table. Finally, the contamination rate was evaluated in each part. A semiquantitative method was used for the analysis of bacterial culture. RESULTS Before the operation, there were four samples tested positive for bacterial culture (1.06%). All of these samples were taken from the most proximal strip near the neckline. After the surgery, the rate of contamination in the strips on the frontal part of the gown was reported as 3.1% to 53%. Based on the operating table, the contamination rate was 35.9%, 8.9%, and 47.3% in the distal, middle, and proximal parts of the gown, respectively. The contamination rate at the elbow crease was 23%, and at 5 and 10 cm above the creases were 24% and 36%, respectively. CONCLUSION The high rate of gown contamination during the operation is concerning. However, part of the gown that was in contact with the operating room table remained clean most of the time. More safe strategies should be used for infection prevention in operating rooms.
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Affiliation(s)
- Mohamad Qoreishi
- Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Bone Joint and Related Tissues Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Research performed at Akhtar hospital, Tehran, Iran
| | - Mohammadreza Abbasian
- Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Bone Joint and Related Tissues Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Research performed at Akhtar hospital, Tehran, Iran
| | - Farshad Safdari
- Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Bone Joint and Related Tissues Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Research performed at Akhtar hospital, Tehran, Iran
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210
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Kane SR, Shah SR, Alfaro TM. Development of a rapid viability polymerase chain reaction method for detection of Yersinia pestis. J Microbiol Methods 2019; 162:21-27. [PMID: 31095987 DOI: 10.1016/j.mimet.2019.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/23/2019] [Accepted: 05/12/2019] [Indexed: 01/14/2023]
Abstract
Due to the occurrence of natural plague outbreaks and its historical usage as a biological weapon, Yersinia pestis is considered one of the high-priority biological threat agents. It can remain viable in certain environments including water for >100 days. Because of its slow-growth characteristic, it usually takes three or more days to detect and confirm the identity of viable Y. pestis cells by PCR, serological, or biochemical assays when using the traditional microbiological plate-culture-based analysis, and that too, assuming faster growing microbes present in a water sample do not mask the Y. pestis colonies and interfere with analysis. Therefore, a rapid-viability Polymerase Chain Reaction (RV-PCR) method was developed for detection of Y. pestis. The RV-PCR method combines 24 h-incubation broth culture in a 48-well plate, and pre- and post-incubation differential PCR analyses, thereby allowing for rapid and high-throughput sample analysis compared with the current plate culture method. One chromosomal and two plasmid gene target-based real-time PCR assays were down-selected, showing ca. 10 genome equivalent detection; the chromosomal assay was then used for RV-PCR method development. A 101-cell level (10-99 cells) sensitivity of detection was demonstrated even with complex sample backgrounds including known PCR inhibitors (ferrous sulfate and humic acid), as well as metal oxides and microbes present in Arizona Test Dust (ATD). The method sensitivity was maintained in the presence of dead Y. pestis cells up to 104 cells per sample. While affording high-throughput and rapid sample analysis, the 48-well plate format used in this method for sample enrichment significantly reduced labor requirements and generation of BioSafety Level-3 (BSL-3) laboratory waste as compared to the usual microbiological plate-culture-based methods. This method may serve as a model for other vegetative bacterial pathogens.
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Affiliation(s)
- Staci R Kane
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Sanjiv R Shah
- National Homeland Security Research Center, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, USA.
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Squire MM, Igusa T, Siddiqui S, Sessel GK, Squire EN. Cost-Effectiveness of Multifaceted Built Environment Interventions for Reducing Transmission of Pathogenic Bacteria in Healthcare Facilities. HERD-HEALTH ENVIRONMENTS RESEARCH & DESIGN JOURNAL 2019; 12:147-161. [PMID: 30991849 DOI: 10.1177/1937586719833360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The objective of this study is to determine the optimal allocation of budgets for pairs of alterations that reduce pathogenic bacterial transmission. Three alterations of the built environment are examined: handwashing stations (HW), relative humidity control (RH), and negatively pressured treatment rooms (NP). These interventions were evaluated to minimize total cost of healthcare-associated infections (HAIs), including medical and litigation costs. BACKGROUND HAIs are largely preventable but are difficult to control because of their multiple mechanisms of transmission. Moreover, the costs of HAIs and resulting mortality are increasing with the latest estimates at US$9.8 billion annually. METHOD Using 6 years of longitudinal multidrug-resistant infection data, we simulated the transmission of pathogenic bacteria and the infection control efforts of the three alterations using Chamchod and Ruan's model. We determined the optimal budget allocations among the alterations by representing them under Karush-Kuhn-Tucker conditions for this nonlinear optimization problem. RESULTS We examined 24 scenarios using three virulence levels across three facility sizes with varying budget levels. We found that in general, most of the budget is allocated to the NP or RH alterations in each intervention. At lower budgets, however, it was necessary to use the lower cost alterations, HW or RH. CONCLUSIONS Mathematical optimization offers healthcare enterprise executives and engineers a tool to assist with the design of safer healthcare facilities within a fiscally constrained environment. Herein, models were developed for the optimal allocation of funds between HW, RH, and negatively pressured treatment rooms (NP) to best reduce HAIs. Specific strategies vary by facility size and virulence.
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Affiliation(s)
- Marietta M Squire
- 1 Department of Civil Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Takeru Igusa
- 1 Department of Civil Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Sauleh Siddiqui
- 1 Department of Civil Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Gareth K Sessel
- 2 Outreach Engineering NPC (non-profit company), Johannesburg, South Africa
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212
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Hui DS, Chow BK, Lo T, Tsang OTY, Ko FW, Ng SS, Gin T, Chan MTV. Exhaled air dispersion during high-flow nasal cannula therapy versus CPAP via different masks. Eur Respir J 2019; 53:13993003.02339-2018. [PMID: 30705129 DOI: 10.1183/13993003.02339-2018] [Citation(s) in RCA: 213] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 01/16/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND High-flow nasal cannula (HFNC) is an emerging therapy for respiratory failure but the extent of exhaled air dispersion during treatment is unknown. We examined exhaled air dispersion during HFNC therapy versus continuous positive airway pressure (CPAP) on a human patient simulator (HPS) in an isolation room with 16 air changes·h-1. METHODS The HPS was programmed to represent different severity of lung injury. CPAP was delivered at 5-20 cmH2O via nasal pillows (Respironics Nuance Pro Gel or ResMed Swift FX) or an oronasal mask (ResMed Quattro Air). HFNC, humidified to 37°C, was delivered at 10-60 L·min-1 to the HPS. Exhaled airflow was marked with intrapulmonary smoke for visualisation and revealed by laser light-sheet. Normalised exhaled air concentration was estimated from the light scattered by the smoke particles. Significant exposure was defined when there was ≥20% normalised smoke concentration. RESULTS In the normal lung condition, mean±sd exhaled air dispersion, along the sagittal plane, increased from 186±34 to 264±27 mm and from 207±11 to 332±34 mm when CPAP was increased from 5 to 20 cmH2O via Respironics and ResMed nasal pillows, respectively. Leakage from the oronasal mask was negligible. Mean±sd exhaled air distances increased from 65±15 to 172±33 mm when HFNC was increased from 10 to 60 L·min-1. Air leakage to 620 mm occurred laterally when HFNC and the interface tube became loose. CONCLUSION Exhaled air dispersion during HFNC and CPAP via different interfaces is limited provided there is good mask interface fitting.
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Affiliation(s)
- David S Hui
- Dept of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.,Stanley Ho Center for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Benny K Chow
- Stanley Ho Center for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Thomas Lo
- Dept of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Owen T Y Tsang
- Dept of Medicine, Princess Margaret Hospital, Hong Kong, Hong Kong SAR, China
| | - Fanny W Ko
- Dept of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Susanna S Ng
- Dept of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Tony Gin
- Dept of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Matthew T V Chan
- Dept of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.,Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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213
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Huang CY, Chin WCB, Wen TH, Fu YH, Tsai YS. EpiRank: Modeling Bidirectional Disease Spread in Asymmetric Commuting Networks. Sci Rep 2019; 9:5415. [PMID: 30931968 PMCID: PMC6443646 DOI: 10.1038/s41598-019-41719-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 03/13/2019] [Indexed: 01/03/2023] Open
Abstract
Commuting network flows are generally asymmetrical, with commuting behaviors bi-directionally balanced between home and work locations, and with weekday commutes providing many opportunities for the spread of infectious diseases via direct and indirect physical contact. The authors use a Markov chain model and PageRank-like algorithm to construct a novel algorithm called EpiRank to measure infection risk in a spatially confined commuting network on Taiwan island. Data from the country's 2000 census were used to map epidemic risk distribution as a commuting network function. A daytime parameter was used to integrate forward and backward movement in order to analyze daily commuting patterns. EpiRank algorithm results were tested by comparing calculations with actual disease distributions for the 2009 H1N1 influenza outbreak and enterovirus cases between 2000 and 2008. Results suggest that the bidirectional movement model outperformed models that considered forward or backward direction only in terms of capturing spatial epidemic risk distribution. EpiRank also outperformed models based on network indexes such as PageRank and HITS. According to a sensitivity analysis of the daytime parameter, the backward movement effect is more important than the forward movement effect for understanding a commuting network's disease diffusion structure. Our evidence supports the use of EpiRank as an alternative network measure for analyzing disease diffusion in a commuting network.
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Affiliation(s)
- Chung-Yuan Huang
- Department of Computer Science and Information Engineering, School of Electrical and Computer Engineering, College of Engineering, Chang Gung University, Taoyuan City, 33302, Taiwan
| | - Wei-Chien-Benny Chin
- Department of Geography, National Taiwan University, Taipei City, 10617, Taiwan.
| | - Tzai-Hung Wen
- Department of Geography, National Taiwan University, Taipei City, 10617, Taiwan
| | - Yu-Hsiang Fu
- Department of Computer Science, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Yu-Shiuan Tsai
- Department of Computer Science and Engineering, National Taiwan Ocean University, Keelung City, 20224, Taiwan
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deKay K, Cahn J. Clinical Issues—March 2019. AORN J 2019; 109:380-389. [DOI: 10.1002/aorn.12627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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215
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Shajahan A, Culp CH, Williamson B. Effects of indoor environmental parameters related to building heating, ventilation, and air conditioning systems on patients' medical outcomes: A review of scientific research on hospital buildings. INDOOR AIR 2019; 29:161-176. [PMID: 30588679 PMCID: PMC7165615 DOI: 10.1111/ina.12531] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 12/10/2018] [Accepted: 12/21/2018] [Indexed: 05/04/2023]
Abstract
The indoor environment of a mechanically ventilated hospital building controls infection rates as well as influences patients' healing processes and overall medical outcomes. This review covers the scientific research that has assessed patients' medical outcomes concerning at least one indoor environmental parameter related to building heating, ventilation, and air conditioning (HVAC) systems, such as indoor air temperature, relative humidity, and indoor air ventilation parameters. Research related to the naturally ventilated hospital buildings was outside the scope of this review article. After 1998, a total of 899 papers were identified that fit the inclusion criteria of this study. Of these, 176 papers have been included in this review to understand the relationship between the health outcomes of a patient and the indoor environment of a mechanically ventilated hospital building. The purpose of this literature review was to summarize how indoor environmental parameters related to mechanical ventilation systems of a hospital building are impacting patients. This review suggests that there is a need for future interdisciplinary collaborative research to quantify the optimum range for HVAC parameters considering airborne exposures and patients' positive medical outcomes.
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Affiliation(s)
- Amreen Shajahan
- Energy Systems LaboratoryTexas A&M UniversityCollege StationTexas
- Department of ArchitectureTexas A&M UniversityCollege StationTexas
| | - Charles H. Culp
- Energy Systems LaboratoryTexas A&M UniversityCollege StationTexas
- Department of ArchitectureTexas A&M UniversityCollege StationTexas
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216
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Küsel RR, Craig IK, Stoltz AC. Modeling the Airborne Infection Risk of Tuberculosis for a Research Facility in eMalahleni, South Africa. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2019; 39:630-646. [PMID: 30229975 DOI: 10.1111/risa.13180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 06/30/2017] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
A detailed mathematical modeling framework for the risk of airborne infectious disease transmission in indoor spaces was developed to enable mathematical analysis of experiments conducted at the Airborne Infections Research (AIR) facility, eMalahleni, South Africa. A model was built using this framework to explore possible causes of why an experiment at the AIR facility did not produce expected results. The experiment was conducted at the AIR facility from August 31, 2015 to December 4, 2015, in which the efficacy of upper room germicidal ultraviolet (GUV) irradiation as an environmental control was tested. However, the experiment did not produce the expected outcome of having fewer infections in the test animal room than the control room. The simulation results indicate that dynamic effects, caused by switching the GUV lights, power outages, or introduction of new patients, did not result in the unexpected outcomes. However, a sensitivity analysis highlights that significant uncertainty exists with risk of transmission predictions based on current measurement practices, due to the reliance on large viable literature ranges for parameters.
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Affiliation(s)
- Ralf R Küsel
- Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria, South Africa
| | - Ian K Craig
- Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria, South Africa
| | - Anton C Stoltz
- Department of Internal Medicine, University of Pretoria, Pretoria, South Africa
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217
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Gola M, Settimo G, Capolongo S. Indoor Air Quality in Inpatient Environments: A Systematic Review on Factors that Influence Chemical Pollution in Inpatient Wards. JOURNAL OF HEALTHCARE ENGINEERING 2019; 2019:8358306. [PMID: 30937154 PMCID: PMC6415317 DOI: 10.1155/2019/8358306] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 11/28/2018] [Accepted: 12/06/2018] [Indexed: 01/14/2023]
Abstract
Introduction Indoor air quality is one the main issues in which governments are focusing. In healing spaces, several research studies are reporting a growing number of data analysis and research works in order to guarantee and prevent health of users and workers. Currently the main investigations are about biological and physical risks; otherwise chemical ones are less investigated. Several countries are carrying out indoor air quality monitoring in those professional workplaces in which chemicals are used but also in some typically indoor (generic) spaces for the building hygiene assessment. The indoor air is affected by several factors that currently are analyzed punctually, without a whole scenario of all the variable performances. The authors have done a systematic review on the current state of the art and knowledge related to chemical pollution in healing spaces and the emerging strategies, supported by scientific literature, for healthy inpatient rooms and their indoor air. Methodology The systematic review has been done through the analysis of papers from SCOPUS, DOAJ, and PubMed databases. The survey sample considered 483 scientific articles, between 1989 and 2017, and starting the systematic reading and analysis of the abstracts, only 187 scientific papers were selected, and only 96 were accessible. Discussion Since scientific literature reports very different outputs and results, the resulting work from the survey is divided into specific fields of interest related to construction and finishing materials, installations, components, ventilation systems, processes, etc. Starting from the systematic reading, the paper classifies the factors of indoor air in four macroareas: outdoor air and microclimatic factors (temperature, relative humidity, air velocity, air change, etc.); management activities (management and maintenance activities, ventilation systems, HVAC, cleaning and disinfectant activities, etc.); design factors (room dimensions, furniture, finishing materials, etc.); and human presence and medical activities (users' presence, their health status, and medical activities carried out in inpatient rooms). Conclusion The systematic review gives rise to a broad scenario on the existing knowledge regarding the indoor air pollution, design, and management strategies for healthy spaces and several emerging topics. Although the aim of the investigation is strictly related to chemical pollution, several considerations from the biological point of view have been listed. The systematic review, supported by the existing scientific literature, becomes a starting point for considering the importance of the topic and to stimulate the knowledge around this field of interest for improving studies, analysis, and simulations.
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Affiliation(s)
- Marco Gola
- Department of Architecture, Built Environment and Construction Engineering (dept. ABC), Politecnico di Milano, Via G. Ponzio 31, 20133 Milan, Italy
| | - Gaetano Settimo
- Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Stefano Capolongo
- Department of Architecture, Built Environment and Construction Engineering (dept. ABC), Politecnico di Milano, Via G. Ponzio 31, 20133 Milan, Italy
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218
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Ravina, Mohan H, Gill PS, Kumar A. Hemagglutinin gene based biosensor for early detection of swine flu (H1N1) infection in human. Int J Biol Macromol 2019; 130:720-726. [PMID: 30822474 DOI: 10.1016/j.ijbiomac.2019.02.149] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 01/07/2019] [Accepted: 02/25/2019] [Indexed: 12/14/2022]
Abstract
Hemagglutinin (HA) is a glycoprotein found on the surface of influenza A subtype virus H1N1 which play a major role in infection to the human by binding the virus to cells with sialic acid on the membrane of upper respiratory tract or erythrocytes. Based on sequence of HA gene an impedimetric biosensor was developed by immobilizing amino labeled single stranded DNA probe onto cysteine modified gold surface of the screen printed electrode for early and rapid detection of H1N1 (Swine flu) in human. The electrochemical impedance was recorded after hybridization of probe with single stranded cDNA (ss-cDNA) of H1N1 patient samples in presence of redox couple. All available methods for detection of H1N1 including RT-PCR are either expensive or time consuming. However, impedimetric biosensor is not only highly specific for H1N1 virus but also can detect as low as 0.004 ng (limit of detection) ss-cDNA in 6 µL only in 30 min. The sensitivity of the sensor was 3750 Ω cm-2 ng-1 of DNA. The biosensor was well characterized using surface cyclic voltammetry, validated with patient samples and compared with existing methods. The sensor can be used in hospitals, diagnostic centres as well as in remote areas for early and rapid diagnosis.
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Affiliation(s)
- Ravina
- Centre for Medical Biotechnology, Maharshi Dayanand University, Rohtak, Haryana 124001, India
| | - Hari Mohan
- Centre for Medical Biotechnology, Maharshi Dayanand University, Rohtak, Haryana 124001, India.
| | - Paramjeet Singh Gill
- Department of Microbiology, Pt. Bhagwat Dyal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana 124001, India
| | - Ashok Kumar
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India.
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219
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Bandaly V, Joubert A, Andres Y, Le Cann P. Adenovirus behavior in air handling unit fiberglass filters. AEROBIOLOGIA 2019; 35:357-366. [PMID: 32214630 PMCID: PMC7087798 DOI: 10.1007/s10453-019-09565-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 01/19/2019] [Indexed: 06/10/2023]
Abstract
Viral aerosols can lead to respiratory viral infections with high infectivity. About 90% of people's time is spent in closed environments. A few studies have pointed out that the ventilation systems in air handling units (AHUs) that treat and transmit a new synthetic clean and conditioned environment can also spread and transport viral particles in buildings. The aim of this work is to study the characterization of adenovirus, a DNA non-enveloped respiratory virus, on the F7 fiberglass filter used in AHUs. In this study, an experimental setup simulating an AHU was used. The SYBR® QPCR, Electrical Low-Pressure Impactor (ELPI™) and Scanning Mobility Particle Sizer (SMPS™) were used to detect, measure and characterize the aerosolized adenovirus solution. The characterization results showed that the nebulized adenovirus could be aerosolized in different forms associated or not with cell debris and proteins. The quantification and level of infectivity of adenovirus demonstrated that viruses passed through filters and remained infectious up- and downstream of the system during the 25 min of aerosolization. This study showed that AHUs should be considered an indoor source of viral contamination.
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Affiliation(s)
- Victor Bandaly
- GEPEA-CNRS, UMR 6144, IMT Atlantique, 44000 Nantes, France
- EHESP, 35000 Rennes, France
- IRSET-INSERM UMR 1085, 35000 Rennes, France
| | | | - Yves Andres
- GEPEA-CNRS, UMR 6144, IMT Atlantique, 44000 Nantes, France
| | - Pierre Le Cann
- EHESP, 35000 Rennes, France
- IRSET-INSERM UMR 1085, 35000 Rennes, France
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220
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Baldini A, Blevins K, Del Gaizo D, Enke O, Goswami K, Griffin W, Indelli PF, Jennison T, Kenanidis E, Manner P, Patel R, Puhto T, Sancheti P, Sharma R, Sharma R, Shetty R, Sorial R, Talati N, Tarity TD, Tetsworth K, Topalis C, Tsiridis E, W-Dahl A, Wilson M. General Assembly, Prevention, Operating Room - Personnel: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019; 34:S97-S104. [PMID: 30360975 PMCID: PMC7111314 DOI: 10.1016/j.arth.2018.09.059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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221
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Tellier R, Li Y, Cowling BJ, Tang JW. Recognition of aerosol transmission of infectious agents: a commentary. BMC Infect Dis 2019. [PMID: 30704406 DOI: 10.1186/s12879-019-3707y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Although short-range large-droplet transmission is possible for most respiratory infectious agents, deciding on whether the same agent is also airborne has a potentially huge impact on the types (and costs) of infection control interventions that are required.The concept and definition of aerosols is also discussed, as is the concept of large droplet transmission, and airborne transmission which is meant by most authors to be synonymous with aerosol transmission, although some use the term to mean either large droplet or aerosol transmission.However, these terms are often used confusingly when discussing specific infection control interventions for individual pathogens that are accepted to be mostly transmitted by the airborne (aerosol) route (e.g. tuberculosis, measles and chickenpox). It is therefore important to clarify such terminology, where a particular intervention, like the type of personal protective equipment (PPE) to be used, is deemed adequate to intervene for this potential mode of transmission, i.e. at an N95 rather than surgical mask level requirement.With this in mind, this review considers the commonly used term of 'aerosol transmission' in the context of some infectious agents that are well-recognized to be transmissible via the airborne route. It also discusses other agents, like influenza virus, where the potential for airborne transmission is much more dependent on various host, viral and environmental factors, and where its potential for aerosol transmission may be underestimated.
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Affiliation(s)
- Raymond Tellier
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Yuguo Li
- Department of Mechanical Engineering, University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region of China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region of China
| | - Julian W Tang
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK. .,Clinical Microbiology, University Hospitals of Leicester NHS Trust, Level 5 Sandringham Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK.
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222
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Tellier R, Li Y, Cowling BJ, Tang JW. Recognition of aerosol transmission of infectious agents: a commentary. BMC Infect Dis 2019; 19:101. [PMID: 30704406 PMCID: PMC6357359 DOI: 10.1186/s12879-019-3707-y] [Citation(s) in RCA: 425] [Impact Index Per Article: 85.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/10/2019] [Indexed: 12/25/2022] Open
Abstract
Although short-range large-droplet transmission is possible for most respiratory infectious agents, deciding on whether the same agent is also airborne has a potentially huge impact on the types (and costs) of infection control interventions that are required.The concept and definition of aerosols is also discussed, as is the concept of large droplet transmission, and airborne transmission which is meant by most authors to be synonymous with aerosol transmission, although some use the term to mean either large droplet or aerosol transmission.However, these terms are often used confusingly when discussing specific infection control interventions for individual pathogens that are accepted to be mostly transmitted by the airborne (aerosol) route (e.g. tuberculosis, measles and chickenpox). It is therefore important to clarify such terminology, where a particular intervention, like the type of personal protective equipment (PPE) to be used, is deemed adequate to intervene for this potential mode of transmission, i.e. at an N95 rather than surgical mask level requirement.With this in mind, this review considers the commonly used term of 'aerosol transmission' in the context of some infectious agents that are well-recognized to be transmissible via the airborne route. It also discusses other agents, like influenza virus, where the potential for airborne transmission is much more dependent on various host, viral and environmental factors, and where its potential for aerosol transmission may be underestimated.
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Affiliation(s)
- Raymond Tellier
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB Canada
| | - Yuguo Li
- Department of Mechanical Engineering, University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region of China
| | - Benjamin J. Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region of China
| | - Julian W. Tang
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
- Clinical Microbiology, University Hospitals of Leicester NHS Trust, Level 5 Sandringham Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
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223
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Villafruela JM, Olmedo I, Berlanga FA, Ruiz de Adana M. Assessment of displacement ventilation systems in airborne infection risk in hospital rooms. PLoS One 2019; 14:e0211390. [PMID: 30699182 PMCID: PMC6353581 DOI: 10.1371/journal.pone.0211390] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/11/2019] [Indexed: 01/07/2023] Open
Abstract
Efficient ventilation in hospital airborne isolation rooms is important vis-à-vis decreasing the risk of cross infection and reducing energy consumption. This paper analyses the suitability of using a displacement ventilation strategy in airborne infection isolation rooms, focusing on health care worker exposure to pathogens exhaled by infected patients. The analysis is mainly based on numerical simulation results obtained with the support of a 3-D transient numerical model validated using experimental data. A thermal breathing manikin lying on a bed represents the source patient and another thermal breathing manikin represents the exposed individual standing beside the bed and facing the patient. A radiant wall represents an external wall exposed to solar radiation. The air change efficiency index and contaminant removal effectiveness indices and inhalation by the health care worker of contaminants exhaled by the patient are considered in a typical airborne infection isolation room set up with three air renewal rates (6 h-1, 9 h-1 and 12 h-1), two exhaust opening positions and two health care worker positions. Results show that the radiant wall significantly affects the air flow pattern and contaminant dispersion. The lockup phenomenon occurs at the inhalation height of the standing manikin. Displacement ventilation renews the air of the airborne isolation room and eliminates the exhaled pollutants efficiently, but is at a disadvantage compared to other ventilation strategies when the risk of exposure is taken into account.
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Affiliation(s)
| | - Inés Olmedo
- Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, Córdoba, Spain
| | - Félix A. Berlanga
- Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, Córdoba, Spain
| | - Manuel Ruiz de Adana
- Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, Córdoba, Spain
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224
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Therkorn J, Drewry III D, Pilholski T, Shaw‐Saliba K, Bova G, Maragakis LL, Garibaldi B, Sauer L. Impact of air-handling system exhaust failure on dissemination pattern of simulant pathogen particles in a clinical biocontainment unit. INDOOR AIR 2019; 29:143-155. [PMID: 30192402 PMCID: PMC7165743 DOI: 10.1111/ina.12506] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 08/17/2018] [Accepted: 09/03/2018] [Indexed: 05/31/2023]
Abstract
Biocontainment units (BCUs) are facilities used to care for patients with highly infectious diseases. However, there is limited guidance on BCU protocols and design. This study presents the first investigation of how HVAC (heating, ventilation, air-conditioning) operating conditions influence the dissemination of fluorescent tracer particles released in a BCU. Test conditions included normal HVAC operation and exhaust failure resulting in loss of negative pressure. A suspension of optical brightener powder and water was nebulized to produce fluorescent particles simulating droplet nuclei (0.5-5 μm). Airborne particle number concentrations were monitored by Instantaneous Biological Analyzers and Collectors (FLIR Systems). During normal HVAC operation, fluorescent tracer particles were contained in the isolation room (average concentration = 1 × 104 ± 3 × 103 /Lair ). Under exhaust failure, the automated HVAC system maximizes airflow into areas adjacent to isolation rooms to attempt to maintain negative pressure differential. However, 6% of the fluorescent particles were transported through cracks around doors/door handles out of the isolation room via airflow alone and not by movement of personnel or doors. Overall, this study provides a systematic method for evaluating capabilities to contain aerosolized particles during various HVAC scenarios. Recommendations are provided to improve situation-specific BCU safety.
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Affiliation(s)
- Jennifer Therkorn
- Applied Biological SciencesJohns Hopkins Applied Physics LaboratoryLaurelMaryland
| | - David Drewry III
- Applied Biological SciencesJohns Hopkins Applied Physics LaboratoryLaurelMaryland
| | - Thomas Pilholski
- Applied Biological SciencesJohns Hopkins Applied Physics LaboratoryLaurelMaryland
| | - Kathryn Shaw‐Saliba
- Johns Hopkins University School of MedicineBaltimoreMaryland
- Johns Hopkins Bloomberg School of Public HealthBaltimoreMaryland
| | | | - Lisa L. Maragakis
- Johns Hopkins University School of MedicineBaltimoreMaryland
- Johns Hopkins Bloomberg School of Public HealthBaltimoreMaryland
- Johns Hopkins Health SystemBaltimoreMaryland
| | - Brian Garibaldi
- Johns Hopkins University School of MedicineBaltimoreMaryland
| | - Lauren Sauer
- Johns Hopkins University School of MedicineBaltimoreMaryland
- Johns Hopkins Bloomberg School of Public HealthBaltimoreMaryland
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225
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Lanzerstorfer A, Hackl M, Schlömer M, Rest B, Deutsch-Grasl E, Lanzerstorfer C. The influence of air-dispersed essential oils from lemon (Citrus limon) and silver fir (Abies alba) on airborne bacteria and fungi in hospital rooms. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2019; 54:256-260. [PMID: 30795725 DOI: 10.1080/10934529.2018.1546498] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Airborne bacteria and fungi are an ongoing problem in hospitals. Because of the antimicrobial activities of essential oils (EOs) dispersion of EOs into the air may help to reduce this contamination. The aim of this study was to evaluate the efficacy of the dispersion of selected EOs in reducing the microbial contamination in two hospital wards. The study was carried out at two wards of a 1,227-bed acute-care hospital in Austria. The concentration of airborne bacteria and fungi was measured in patient rooms before and after dispersion of a mixture of Citrus limon EO and Abies alba EO. Before dispersion of the EOs in both wards the mean concentration of bacteria was in a typical range (123 colony forming units (CFU) m-3 and 104 CFU m-3) while the mean concentration of fungi differed substantially (155 CFU m-3 and 28 CFU m-3). After dispersion of the EOs, a reduction in both bacterial and fungal contamination was observed. In the first two hours the mean concentration of airborne bacteria and fungi was reduced by approximately 40% and 30%-60% respectively. The selected EO mixture is effective in reducing the microbial contamination of the indoor air.
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Affiliation(s)
| | - Melanie Hackl
- b School of Engineering/Environmental Sciences , University of Applied Sciences Upper Austria , Wels , Austria
| | - Matthias Schlömer
- b School of Engineering/Environmental Sciences , University of Applied Sciences Upper Austria , Wels , Austria
| | - Brigitte Rest
- c Aromapflege Gesundheitsschule Evelyn Deutsch , Lechaschau , Austria
| | - Evelyn Deutsch-Grasl
- c Aromapflege Gesundheitsschule Evelyn Deutsch , Lechaschau , Austria
- d Aromapflege GmbH , Lechaschau , Austria
| | - Christof Lanzerstorfer
- b School of Engineering/Environmental Sciences , University of Applied Sciences Upper Austria , Wels , Austria
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226
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Kennedy M, Ramsheh MY, Williams CML, Auty J, Haldar K, Abdulwhhab M, Brightling CE, Barer MR. Face mask sampling reveals antimicrobial resistance genes in exhaled aerosols from patients with chronic obstructive pulmonary disease and healthy volunteers. BMJ Open Respir Res 2018; 5:e000321. [PMID: 30271606 PMCID: PMC6157532 DOI: 10.1136/bmjresp-2018-000321] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/13/2018] [Indexed: 11/30/2022] Open
Abstract
Introduction The degree to which bacteria in the human respiratory tract are aerosolised by individuals is not established. Building on our experience sampling bacteria exhaled by individuals with pulmonary tuberculosis using face masks, we hypothesised that patients with conditions frequently treated with antimicrobials, such as chronic obstructive pulmonary disease (COPD), might exhale significant numbers of bacteria carrying antimicrobial resistance (AMR) genes and that this may constitute a previously undefined risk for the transmission of AMR. Methods Fifteen-minute mask samples were taken from 13 patients with COPD (five paired with contemporaneous sputum samples) and 10 healthy controls. DNA was extracted from cell pellets derived from gelatine filters mounted within the mask. Quantitative PCR analyses directed to the AMR encoding genes: blaTEM (β-lactamase), ErmB (target methylation), mefA (macrolide efflux pump) and tetM (tetracycline ribosomal protection protein) and six additional targets were investigated. Positive signals above control samples were obtained for all the listed genes; however, background signals from the gelatine precluded analysis of the additional targets. Results 9 patients with COPD (69%), aerosolised cells containing, in order of prevalence, mefA, tetM, ErmB and blaTEM, while three healthy controls (30%) gave weak positive signals including all targets except blaTEM. Maximum estimated copy numbers of AMR genes aerosolised per minute were mefA: 3010, tetM: 486, ErmB: 92 and blaTEM: 24. The profile of positive signals found in sputum was not concordant with that in aerosol in multiple instances. Discussion We identified aerosolised AMR genes in patients repeatedly exposed to antimicrobials and in healthy volunteers at lower frequencies and levels. The discrepancies between paired samples add weight to the view that sputum content does not define aerosol content. Mask sampling is a simple approach yielding samples from all subjects and information distinct from sputum analysis. Our results raise the possibility that patient-generated aerosols may be a significant means of AMR dissemination that should be assessed further and that consideration be given to related control measures.
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Affiliation(s)
- Matthew Kennedy
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK.,Department of Clinical Microbiology, University Hospitals of Leicester, Leicester, UK
| | - Mohammadali Y Ramsheh
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Caroline M L Williams
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Joss Auty
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Koirobi Haldar
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Mohamad Abdulwhhab
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Christopher E Brightling
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK.,Department of Clinical Microbiology, University Hospitals of Leicester, Leicester, UK
| | - Michael R Barer
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK.,Department of Clinical Microbiology, University Hospitals of Leicester, Leicester, UK
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227
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Sadrizadeh S, Pantelic J, Sherman M, Clark J, Abouali O. Airborne particle dispersion to an operating room environment during sliding and hinged door opening. J Infect Public Health 2018. [DOI: 10.1016/j.jiph.2018.02.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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228
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Epidemiology, Biology, and Impact of Clonal Pseudomonas aeruginosa Infections in Cystic Fibrosis. Clin Microbiol Rev 2018; 31:31/4/e00019-18. [PMID: 30158299 DOI: 10.1128/cmr.00019-18] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chronic lower airway infection with Pseudomonas aeruginosa is a major contributor to morbidity and mortality in individuals suffering from the genetic disease cystic fibrosis (CF). Whereas it was long presumed that each patient independently acquired unique strains of P. aeruginosa present in their living environment, multiple studies have since demonstrated that shared strains of P. aeruginosa exist among individuals with CF. Many of these shared strains, often referred to as clonal or epidemic strains, can be transmitted from one CF individual to another, potentially reaching epidemic status. Numerous epidemic P. aeruginosa strains have been described from different parts of the world and are often associated with an antibiotic-resistant phenotype. Importantly, infection with these strains often portends a worse prognosis than for infection with nonclonal strains, including an increased pulmonary exacerbation rate, exaggerated lung function decline, and progression to end-stage lung disease. This review describes the global epidemiology of clonal P. aeruginosa strains in CF and summarizes the current literature regarding the underlying biology and clinical impact of globally important CF clones. Mechanisms associated with patient-to-patient transmission are discussed, and best-evidence practices to prevent infections are highlighted. Preventing new infections with epidemic P. aeruginosa strains is of paramount importance in mitigating CF disease progression.
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Ai ZT, Melikov AK. Airborne spread of expiratory droplet nuclei between the occupants of indoor environments: A review. INDOOR AIR 2018; 28:500-524. [PMID: 29683213 DOI: 10.1111/ina.12465] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 04/13/2018] [Indexed: 05/04/2023]
Abstract
This article reviews past studies of airborne transmission between occupants in indoor environments, focusing on the spread of expiratory droplet nuclei from mouth/nose to mouth/nose for non-specific diseases. Special attention is paid to summarizing what is known about the influential factors, the inappropriate simplifications of the thermofluid boundary conditions of thermal manikins, the challenges facing the available experimental techniques, and the limitations of available evaluation methods. Secondary issues are highlighted, and some new ways to improve our understanding of airborne transmission indoors are provided. The characteristics of airborne spread of expiratory droplet nuclei between occupants, which are influenced correlatively by both environmental and personal factors, were widely revealed under steady-state conditions. Owing to the different boundary conditions used, some inconsistent findings on specific influential factors have been published. The available instrumentation was too slow to provide accurate concentration profiles for time-dependent evaluations of events with obvious time characteristics, while computational fluid dynamics (CFD) studies were mainly performed in the framework of inherently steady Reynolds-averaged Navier-Stokes modeling. Future research needs in 3 areas are identified: the importance of the direction of indoor airflow patterns, the dynamics of airborne transmission, and the application of CFD simulations.
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Affiliation(s)
- Z T Ai
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Copenhagen, Denmark
| | - A K Melikov
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Copenhagen, Denmark
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230
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Mu D, Gao N, Zhu T. CFD investigation on the effects of wind and thermal wall-flow on pollutant transmission in a high-rise building. BUILDING AND ENVIRONMENT 2018; 137:185-197. [PMID: 32287985 PMCID: PMC7127015 DOI: 10.1016/j.buildenv.2018.03.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/28/2018] [Accepted: 03/28/2018] [Indexed: 05/04/2023]
Abstract
The solar radiation can heat the building outer surface, and then cause the upward natural convection flows adjacent to the wall. This phenomenon is especially obvious on a windless sunny day. The near wall thermal plume can drive gaseous pollutants released from lower floors to upper floors. Combined with the effect of ambient approaching wind, the transmission routes will be very complicated. The paper aims to investigate the airflow patterns and pollutant transmission within a building under the effects of wind and thermal forces. A hypothetical twenty-storey slab-shape high-rise building in Shanghai with single-sided natural ventilation is set as the research object in the present study. The intensity of solar radiation on a typical day during transition season is theoretically analysed. The temperature difference between the heated building envelope and the ambient air is calculated by a simplified heat balance model. Finally, the tracer gas method is employed in the numerical simulation to analyse the influence of the wind and wall thermal plume flow on the inter-flat pollutant transmission characteristics. The results show that, the temperature difference between sunward and shady side wall is about 10 K at noon on the designate day. When the source is set as a point with steady intensity and the buoyancy is stronger than or approximately equivalent to the wind, the reentry ratio of the flat immediately above the source can be around 25%.
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Affiliation(s)
| | - Naiping Gao
- School of Mechanical Engineering, Tongji University, Shanghai, China
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231
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Calderwood AH, Day LW, Muthusamy VR, Collins J, Hambrick RD, Brock AS, Guda NM, Buscaglia JM, Petersen BT, Buttar NS, Khanna LG, Kushnir VM, Repaka A, Villa NA, Eisen GM. ASGE guideline for infection control during GI endoscopy. Gastrointest Endosc 2018; 87:1167-1179. [PMID: 29573782 DOI: 10.1016/j.gie.2017.12.009] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 12/15/2017] [Indexed: 02/08/2023]
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232
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Bing-Yuan, Zhang YH, Leung NH, Cowling BJ, Yang ZF. Role of viral bioaerosols in nosocomial infections and measures for prevention and control. JOURNAL OF AEROSOL SCIENCE 2018; 117:200-211. [PMID: 32226118 PMCID: PMC7094610 DOI: 10.1016/j.jaerosci.2017.11.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 11/21/2017] [Accepted: 11/23/2017] [Indexed: 09/21/2023]
Abstract
The presence of patients with diverse pathologies in hospitals results in an environment that can be rich in various microorganisms including respiratory and enteric viruses, leading to outbreaks in hospitals or spillover infections to the community. All hospital patients are at risk of nosocomial viral infections, but vulnerable groups such as older adults, children and immuno-compromised/-suppressed patients are at particular risk of severe outcomes including prolonged hospitalization or death. These pathogens could transmit through direct or indirect physical contact, droplets or aerosols, with increasing evidence suggesting the importance of aerosol transmission in nosocomial infections of respiratory and enteric viruses. Factors affecting the propensity to transmit and the severity of disease transmitted via the aerosol route include the biological characteristics affecting infectivity of the viruses and susceptibility of the host, the physical properties of aerosol particles, and the environmental stresses that alter these properties such as temperature and humidity. Non-specific systematic and individual-based interventions designed to mitigate the aerosol route are available although empirical evidence of their effectiveness in controlling transmission of respiratory and enteric viruses in healthcare settings are sparse. The relative importance of aerosol transmission in healthcare setting is still an on-going debate, with particular challenge being the recovery of infectious viral bioaerosols from real-life settings and the difficulty in delineating transmission events that may also be a result of other modes of transmission. For the prevention and control of nosocomial infections via the aerosol route, more research is needed on identifying settings, medical procedures or equipment that may be associated with an increased risk of aerosol transmission, including defining which procedures are aerosol-generating; and on the effectiveness of systematic interventions on aerosol transmission of respiratory and enteric viruses in healthcare settings.
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Affiliation(s)
- Bing-Yuan
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, No. 151, Yanjiangxi Road, Yuexiu District, Guangzhou, Guangdong 510120, China
- Department of Respiration, First People's Hospital of Yunnan Province, 157, Jinbi Road, Kunming, Yunnan 650032, China
| | - Yun-Hui Zhang
- Department of Respiration, First People's Hospital of Yunnan Province, 157, Jinbi Road, Kunming, Yunnan 650032, China
| | - Nancy H.L. Leung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Patrick Manson Building (North Wing), 7 Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Benjamin J. Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Patrick Manson Building (North Wing), 7 Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Zi-Feng Yang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, No. 151, Yanjiangxi Road, Yuexiu District, Guangzhou, Guangdong 510120, China
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233
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Transmission routes of respiratory viruses among humans. Curr Opin Virol 2018; 28:142-151. [PMID: 29452994 PMCID: PMC7102683 DOI: 10.1016/j.coviro.2018.01.001] [Citation(s) in RCA: 342] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 12/28/2017] [Accepted: 01/03/2018] [Indexed: 01/03/2023]
Abstract
Respiratory tract infections can be caused by a wide variety of viruses. Airborne transmission via droplets and aerosols enables some of these viruses to spread efficiently among humans, causing outbreaks that are difficult to control. Many outbreaks have been investigated retrospectively to study the possible routes of inter-human virus transmission. The results of these studies are often inconclusive and at the same time data from controlled experiments is sparse. Therefore, fundamental knowledge on transmission routes that could be used to improve intervention strategies is still missing. We here present an overview of the available data from experimental and observational studies on the transmission routes of respiratory viruses between humans, identify knowledge gaps, and discuss how the available knowledge is currently implemented in isolation guidelines in health care settings.
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234
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Bache S, Maclean M, Gettinby G, Anderson J, MacGregor S, Taggart I. Universal decontamination of hospital surfaces in an occupied inpatient room with a continuous 405 nm light source. J Hosp Infect 2018; 98:67-73. [DOI: 10.1016/j.jhin.2017.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/11/2017] [Indexed: 10/19/2022]
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235
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An Effective Surrogate Tracer Technique for S. aureus Bioaerosols in a Mechanically Ventilated Hospital Room Replica Using Dilute Aqueous Lithium Chloride. ATMOSPHERE 2017. [DOI: 10.3390/atmos8120238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Finding a non-pathogenic surrogate aerosol that represents the deposition of typical bioaerosols in healthcare settings is beneficial from the perspective of hospital facility testing, general infection control and outbreak analysis. This study considers aerosolization of dilute aqueous lithium chloride (LiCl) and sodium chloride (NaCl) solutions as surrogate tracers capable of representing Staphylococcus aureus bioaerosol deposition on surfaces in mechanically ventilated rooms. Tests were conducted in a biological test chamber set up as a replica hospital single patient room. Petri dishes on surfaces were used to collect the Li, Na and S. aureus aerosols separately after release. Biological samples were analyzed using cultivation techniques on solid media, and flame atomic absorption spectroscopy was used to measure Li and Na atom concentrations. Spatial deposition distribution of Li tracer correlated well with S. aureus aerosols (96% of pairs within a 95% confidence interval). In the patient hospital room replica, results show that the most contaminated areas were on surfaces 2 m away from the source. This indicates that the room’s airflow patterns play a significant role in bioaerosol transport. NaCl proved not to be sensitive to spatial deposition patterns. LiCl as a surrogate tracer for bioaerosol deposition was most reliable as it was robust to outliers, sensitive to spatial heterogeneity and found to require less replicates than the S. aureus counterpart to be in good spatial agreement with biological results.
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236
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Bandaly V, Joubert A, Le Cann P, Andres Y. The Fate of Mengovirus on Fiberglass Filter of Air Handling Units. FOOD AND ENVIRONMENTAL VIROLOGY 2017; 9:464-472. [PMID: 28660425 PMCID: PMC7090558 DOI: 10.1007/s12560-017-9310-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation, and air-conditioning systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, and fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces, or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber filter F7 used in AHU. In this study, a set-up close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the electrical low pressure impact and the scanner mobility particle size and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the filter and in the biosampler showed that mengovirus can pass through the filter and remain infectious upstream and downstream the system. Regarding the virus infectivity on the filter under a constant air flow, mengovirus was remained infectious during 10 h after aerosolization.
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Affiliation(s)
- Victor Bandaly
- GEPEA-CNRS, UMR 6144, IMT Atlantique, 44000, Nantes, France.
- EHESP, 35000, Rennes, France.
- IRSET-INSERM, UMR 1085, 35000, Rennes, France.
| | | | - Pierre Le Cann
- EHESP, 35000, Rennes, France
- IRSET-INSERM, UMR 1085, 35000, Rennes, France
| | - Yves Andres
- GEPEA-CNRS, UMR 6144, IMT Atlantique, 44000, Nantes, France
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237
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Saarinen P, Kalliomäki P, Koskela H, Tang JW. Large-eddy simulation of the containment failure in isolation rooms with a sliding door-An experimental and modelling study. BUILDING SIMULATION 2017; 11:585-596. [PMID: 32218903 PMCID: PMC7091416 DOI: 10.1007/s12273-017-0422-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/24/2017] [Accepted: 10/11/2017] [Indexed: 05/05/2023]
Abstract
In hospital isolation rooms, door operation can lead to containment failures and airborne pathogen dispersal into the surrounding spaces. Sliding doors can reduce the containment failure arising from the door motion induced airflows, as compared to the hinged doors that are typically used in healthcare facilities. Such airflow leakage can be measured quantitatively using tracer gas techniques, but detailed observation of the turbulent flow features is very difficult. However, a comprehensive understanding of these flows is important when designing doors to further reduce such containment failures. Experiments and Computational Fluid Dynamics (CFD) modelling, by using Large-Eddy Simulation (LES) flow solver, were used to study airflow patterns in a full-scale mock-up, consisting of a sliding door separating two identical rooms (i.e. one isolation room attached to an antechamber). A single sliding door open/ hold-open/ closing cycle was studied. Additional variables included human passage through the doorway and imposing a temperature difference between the two rooms. The general structures of computationally-simulated flow features were validated by comparing the results to smoke visualizations of identical full-scale experimental set-ups. It was found that without passage the air volume leakage across the doorway was first dominated by vortex shedding in the wake of the door, but during a prolonged hold-open period a possible temperature difference soon became the predominant driving force. Passage generates a short and powerful pulse of leakage flow rate even if the walker stops to wait for the door to open. ELECTRONIC SUPPLEMENTARY MATERIAL ESM supplementary material is available in the online version of this article at 10.1007/s12273-017-0422-8.
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Affiliation(s)
- Pekka Saarinen
- Finnish Institute of Occupational Health, Turku, Finland
- Turku University of Applied Sciences, Turku, Finland
| | - Petri Kalliomäki
- Finnish Institute of Occupational Health, Turku, Finland
- Turku University of Applied Sciences, Turku, Finland
| | - Hannu Koskela
- Finnish Institute of Occupational Health, Turku, Finland
- Turku University of Applied Sciences, Turku, Finland
| | - Julian W. Tang
- Leicester Royal Infirmary, University Hospitals Leicester, Leicester, UK
- Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
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238
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Abstract
As of January 2016, 1,633 laboratory-confirmed cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection and 587 MERS-related deaths have been reported by the World Health Organization globally. Middle East Respiratory Syndrome Coronavirus may occur sporadically in communities or may be transmitted within families or hospitals. The number of confirmed MERS-CoV cases among healthcare workers has been increasing. Middle East Respiratory Syndrome Coronavirus may also spread through aerosols generated during various dental treatments, resulting in transmission between patients and dentists. As MERS-CoV cases have also been reported among children, pediatric dentists are at risk of MERS-CoV infection. This review discusses MERS-CoV infection in children and healthcare workers, especially pediatric dentists, and considerations pertaining to pediatric dentistry. Although no cases of MERS-CoV transmission between a patient and a dentist have yet been reported, the risk of MERS-CoV transmission from an infected patient may be high due to the unique work environment of dentists (aerosol generation).
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Affiliation(s)
- Fares S Al-Sehaibany
- Division of Pediatric Dentistry, Department of Pediatric Dentistry and Orthodontics, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia. E-mail.
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239
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Pereira ML, Knibbs LD, He C, Grzybowski P, Johnson GR, Huffman JA, Bell SC, Wainwright CE, Matte DL, Dominski FH, Andrade A, Morawska L. Sources and dynamics of fluorescent particles in hospitals. INDOOR AIR 2017; 27:988-1000. [PMID: 28303606 DOI: 10.1111/ina.12380] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 03/12/2017] [Indexed: 06/06/2023]
Abstract
Fluorescent particles can be markers of bioaerosols and are therefore relevant to nosocomial infections. To date, little research has focused on fluorescent particles in occupied indoor environments, particularly hospitals. In this study, we aimed to determine the spatial and temporal variation of fluorescent particles in two large hospitals in Brisbane, Australia (one for adults and one for children). We used an Ultraviolet Aerodynamic Particle Sizer (UVAPS) to identify fluorescent particle sources, as well as their contribution to total particle concentrations. We found that the average concentrations of both fluorescent and non-fluorescent particles were higher in the adults' hospital (0.06×106 and 1.20×106 particles/m3 , respectively) than in the children's hospital (0.03×106 and 0.33×106 particles/m3 , respectively) (P<.01). However, the proportion of fluorescent particles was higher in the children's hospital. Based on the concentration results and using activity diaries, we were able to identify sources of particle production within the two hospitals. We demonstrated that particles can be easily generated by a variety of everyday activities, which are potential sources of exposure to pathogens. Future studies to further investigate their role in nosocomial infection are warranted.
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Affiliation(s)
- M L Pereira
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia
- Department of Refrigeration and Air Conditioning, Federal Institute of Education, Science and Technology of Santa Catarina, Santa Catarina, Brazil
| | - L D Knibbs
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia
- School of Public Health, The University of Queensland, Herston, Qld, Australia
| | - C He
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia
| | - P Grzybowski
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia
- Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland
| | - G R Johnson
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia
| | - J A Huffman
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, USA
| | - S C Bell
- Thoracic Medicine, Prince Charles Hospital, Chermside, Qld, Australia
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Herston, Qld, Australia
| | - C E Wainwright
- School of Medicine, University of Queensland, Herston, Qld, Australia
- Department of Respiratory and Sleep Medicine, Lady Cilento Children's Hospital, South Brisbane, Qld, Australia
| | - D L Matte
- Center of Health Sciences and Sport, Santa Catarina State University, Florianópolis, Brazil
| | - F H Dominski
- Center of Health Sciences and Sport, Santa Catarina State University, Florianópolis, Brazil
| | - A Andrade
- Center of Health Sciences and Sport, Santa Catarina State University, Florianópolis, Brazil
| | - L Morawska
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia
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240
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Weaver AM, Parveen S, Goswami D, Crabtree-Ide C, Rudra C, Yu J, Mu L, Fry AM, Sharmin I, Luby SP, Ram PK. Pilot Intervention Study of Household Ventilation and Fine Particulate Matter Concentrations in a Low-Income Urban Area, Dhaka, Bangladesh. Am J Trop Med Hyg 2017; 97:615-623. [PMID: 28722632 DOI: 10.4269/ajtmh.16-0326] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Fine particulate matter (PM2.5) is a risk factor for pneumonia; ventilation may be protective. We tested behavioral and structural ventilation interventions on indoor PM2.5 in Dhaka, Bangladesh. We recruited 59 good ventilation (window or door in ≥ 3 walls) and 29 poor ventilation (no window, one door) homes. We monitored baseline indoor and outdoor PM2.5 for 48 hours. We asked all participants to increase ventilation behavior, including opening windows and doors, and operating fans. Where permitted, we installed windows in nine poor ventilation homes, then repeated PM2.5 monitoring. We estimated effects using linear mixed-effects models and conducted qualitative interviews regarding motivators and barriers to ventilation. Compared with poor ventilation homes, good ventilation homes were larger, their residents wealthier and less likely to use biomass fuel. In multivariable linear mixed-effects models, ventilation structures and opening a door or window were inversely associated with the number of hours PM2.5 concentrations exceeded 100 and 250 μg/m3. Outdoor air pollution was positively associated with the number of hours PM2.5 concentrations exceeded 100 and 250 μg/m3. Few homes accepted window installation, due to landlord refusal and fear of theft. Motivators for ventilation behavior included cooling of the home and sunlight; barriers included rain, outdoor odors or noise, theft risk, mosquito entry, and, for fan use, perceptions of wasting electricity or unavailability of electricity. We concluded that ventilation may reduce indoor PM2.5 concentrations but, there are barriers to increasing ventilation and, in areas with high ambient PM2.5 concentrations, indoor concentrations may remain above recommended levels.
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Affiliation(s)
- Anne M Weaver
- Richard M. Fairbanks School of Public Health, Indiana University, Indianapolis, Indiana.,Department of Epidemiology and Environmental Health, University at Buffalo, Buffalo, New York
| | - Shahana Parveen
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Doli Goswami
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Christina Crabtree-Ide
- Department of Epidemiology and Environmental Health, University at Buffalo, Buffalo, New York
| | - Carole Rudra
- Department of Epidemiology and Environmental Health, University at Buffalo, Buffalo, New York
| | - Jihnhee Yu
- Department of Biostatistics, University at Buffalo, Buffalo, New York
| | - Lina Mu
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Alicia M Fry
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Iffat Sharmin
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Stephen P Luby
- Stanford University, Stanford, California.,International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Pavani K Ram
- Department of Epidemiology and Environmental Health, University at Buffalo, Buffalo, New York
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241
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Junter GA, Lebrun L. Cellulose-based virus-retentive filters: a review. RE/VIEWS IN ENVIRONMENTAL SCIENCE AND BIO/TECHNOLOGY 2017; 16:455-489. [PMID: 32214924 PMCID: PMC7088658 DOI: 10.1007/s11157-017-9434-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption-elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.
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Affiliation(s)
- Guy-Alain Junter
- Normandie Univ, UNIROUEN Normandie, INSA Rouen, CNRS, PBS, 76000 Rouen, France
| | - Laurent Lebrun
- Normandie Univ, UNIROUEN Normandie, INSA Rouen, CNRS, PBS, 76000 Rouen, France
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242
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DETECTION OF AEROSOLIZED BACTERIA IN EXPIRED AIR SAMPLES FROM ASIAN ELEPHANTS ( ELEPHAS MAXIMUS). J Zoo Wildl Med 2017; 48:431-439. [DOI: 10.1638/2016-0119r.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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243
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Shamsizadeh Z, Nikaeen M, Nasr Esfahani B, Mirhoseini SH, Hatamzadeh M, Hassanzadeh A. Detection of antibiotic resistant Acinetobacter baumannii in various hospital environments: potential sources for transmission of Acinetobacter infections. Environ Health Prev Med 2017; 22:44. [PMID: 29165152 PMCID: PMC5664838 DOI: 10.1186/s12199-017-0653-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 04/20/2017] [Indexed: 11/10/2022] Open
Abstract
Background Antibiotic resistant Acinetobacter baumannii has emerged as one of the most problematic hospital acquired pathogens around the world. This study was designed to investigate the presence of antibiotic resistant A. baumannii in various hospital environments. Methods Air, water and inanimate surface samples were taken in different wards of four hospitals and analyzed for the presence of A. baumannii. Confirmed A. baumannii isolates were analyzed for antimicrobial susceptibility and also screened for the presence of three most common OXA- type carbapenemase-encoding genes. Results A. baumannii was detected in 11% (7/64) of air samples with the highest recovery in intensive care units (ICUs). A. baumannii was also detected in 17% (7/42) and 2% (1/42) of surface and water samples, respectively. A total of 40 A. baumannii isolates were recovered and analysis of antimicrobial susceptibility showed the highest resistance towards ceftazidime (92.5%, 37/40). 85% (34/40) and 80% (32/40) of the isolates were also resistant to imipenem and gentamicin, respectively. Resistance genes analysis showed that 77.5% (31/40) strains contained OXA-23 and 5% (2/40) strains contained OXA-24, but OXA-58 was not detected in any of the strains. Conclusion Detection of antibiotic resistant A. baumannii in various samples revealed that hospital environments could act as a potential source for transmission of A. baumannii infections especially in ICUs. These results emphasize the importance of early detection and implementation of control measures to prevent the spread of A. baumannii in hospital environments.
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Affiliation(s)
- Zahra Shamsizadeh
- Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Hezar Jerib Avenue, Isfahan, Iran
| | - Mahnaz Nikaeen
- Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Hezar Jerib Avenue, Isfahan, Iran.
| | - Bahram Nasr Esfahani
- Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Seyed Hamed Mirhoseini
- Department of Environmental Health Engineering, School of Health, Arak University of Medical Sciences, Arak, Iran
| | - Maryam Hatamzadeh
- Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Hezar Jerib Avenue, Isfahan, Iran
| | - Akbar Hassanzadeh
- Department of Statistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
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244
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Mu D, Shu C, Gao N, Zhu T. Wind tunnel tests of inter-flat pollutant transmission characteristics in a rectangular multi-storey residential building, part B: Effect of source location. BUILDING AND ENVIRONMENT 2017; 114:281-292. [PMID: 32287970 PMCID: PMC7117001 DOI: 10.1016/j.buildenv.2016.12.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/22/2016] [Accepted: 12/23/2016] [Indexed: 05/19/2023]
Abstract
The pollutant behavior in and around a naturally ventilated building requires to be investigated quantitatively as the growing concern on air quality within the built environment. The objective of the present study is to further investigate the wind induced inter-flat pollutant transmission and cross contamination routes in typical buildings in Shanghai. In this paper, a set of experiments was carried out in a boundary layer wind tunnel using a 1:30 reduced scale model that represented the typical configuration of rectangular multi-storey residential buildings. Sulfur hexafluoride (SF6) was employed as a tracer gas in the wind tunnel tests. Two natural ventilation modes, single-sided ventilation and cross ventilation were considered. The conditions under prevailing wind direction with different source locations on the windward side were compared. The pressure coefficients on all of the building façades and tracer gas concentration distributions were monitored and analysed. The experimental results elucidated that contaminant released from windward units could spread vertically and horizontally to other units on the source façade and downstream units. The source location was a significant influence factor on the pollutant concentration in various units. In the single-sided ventilated building, the infected risks of leeward units were even higher than those in some windward units. In the cross ventilated building, the vertical transmission could be suppressed and the horizontal transmission was reinforced. The study is helpful for further understanding of the inter-flat airborne transmission within an isolated building.
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Affiliation(s)
| | | | - Naiping Gao
- School of Mechanical Engineering, Tongji University, Shanghai, China
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245
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Liu L, Li Y, Nielsen PV, Wei J, Jensen RL. Short-range airborne transmission of expiratory droplets between two people. INDOOR AIR 2017; 27:452-462. [PMID: 27287598 DOI: 10.1111/ina.12314] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 06/07/2016] [Indexed: 05/04/2023]
Abstract
The occurrence of close proximity infection for many respiratory diseases is often cited as evidence of large droplet and/or close contact transmission. We explored interpersonal exposure of exhaled droplets and droplet nuclei of two standing thermal manikins as affected by distance, humidity, ventilation, and breathing mode. Under the specific set of conditions studied, we found a substantial increase in airborne exposure to droplet nuclei exhaled by the source manikin when a susceptible manikin is within about 1.5 m of the source manikin, referred to as the proximity effect. The threshold distance of about 1.5 m distinguishes the two basic transmission processes of droplets and droplet nuclei, that is, short-range modes and the long-range airborne route. The short-range modes include both the conventional large droplet route and the newly defined short-range airborne transmission. We thus reveal that transmission occurring in close proximity to the source patient includes both droplet-borne (large droplet) and short-range airborne routes, in addition to the direct deposition of large droplets on other body surfaces. The mechanisms of the droplet-borne and short-range airborne routes are different; their effective control methods also differ. Neither the current droplet precautions nor dilution ventilation prevents short-range airborne transmission, so new control methods are needed.
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Affiliation(s)
- L Liu
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
- Department of Civil Engineering, Aalborg University, Aalborg SV, Denmark
| | - Y Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - P V Nielsen
- Department of Civil Engineering, Aalborg University, Aalborg SV, Denmark
| | - J Wei
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - R L Jensen
- Department of Civil Engineering, Aalborg University, Aalborg SV, Denmark
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246
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Assessing the social and environmental determinants of pertussis epidemics in Queensland, Australia: a Bayesian spatio-temporal analysis. Epidemiol Infect 2017; 145:1221-1230. [PMID: 28091337 DOI: 10.1017/s0950268816003289] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Pertussis epidemics have displayed substantial spatial heterogeneity in countries with high socioeconomic conditions and high vaccine coverage. This study aims to investigate the relationship between pertussis risk and socio-environmental factors on the spatio-temporal variation underlying pertussis infection. We obtained daily case numbers of pertussis notifications from Queensland Health, Australia by postal area, for the period January 2006 to December 2012. A Bayesian spatio-temporal model was used to quantify the relationship between monthly pertussis incidence and socio-environmental factors. The socio-environmental factors included monthly mean minimum temperature (MIT), monthly mean vapour pressure (VAP), Queensland school calendar pattern (SCP), and socioeconomic index for area (SEIFA). An increase in pertussis incidence was observed from 2006 to 2010 and a slight decrease from 2011 to 2012. Spatial analyses showed pertussis incidence across Queensland postal area to be low and more spatially homogeneous during 2006-2008; incidence was higher and more spatially heterogeneous after 2009. The results also showed that the average decrease in monthly pertussis incidence was 3·1% [95% credible interval (CrI) 1·3-4·8] for each 1 °C increase in monthly MIT, while average increase in monthly pertussis incidences were 6·2% (95% CrI 0·4-12·4) and 2% (95% CrI 1-3) for SCP periods and for each 10-unit increase in SEIFA, respectively. This study demonstrated that pertussis transmission is significantly associated with MIT, SEIFA, and SCP. Mapping derived from this work highlights the potential for future investigation and areas for focusing future control strategies.
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247
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Viral Infections, an Overview with a Focus on Prevention of Transmission. INTERNATIONAL ENCYCLOPEDIA OF PUBLIC HEALTH 2017. [PMCID: PMC7150291 DOI: 10.1016/b978-0-12-803678-5.00514-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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248
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Weaver AM, Khatun-E-Jannat K, Cercone E, Krytus K, Sohel BM, Ahmed M, Rahman M, Azziz-Baumgartner E, Yu J, Fry AM, Luby SP, Ram PK. Household-level risk factors for secondary influenza-like illness in a rural area of Bangladesh. Trop Med Int Health 2016; 22:187-195. [PMID: 27889937 PMCID: PMC7169715 DOI: 10.1111/tmi.12820] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Objective To describe household‐level risk factors for secondary influenza‐like illness (ILI), an important public health concern in the low‐income population of Bangladesh. Methods Secondary analysis of control participants in a randomised controlled trial evaluating the effect of handwashing to prevent household ILI transmission. We recruited index‐case patients with ILI – fever (<5 years); fever, cough or sore throat (≥5 years) – from health facilities, collected information on household factors and conducted syndromic surveillance among household contacts for 10 days after resolution of index‐case patients’ symptoms. We evaluated the associations between household factors at baseline and secondary ILI among household contacts using negative binomial regression, accounting for clustering by household. Results Our sample was 1491 household contacts of 184 index‐case patients. Seventy‐one percentage reported that smoking occurred in their home, 27% shared a latrine with one other household and 36% shared a latrine with >1 other household. A total of 114 household contacts (7.6%) had symptoms of ILI during follow‐up. Smoking in the home (RRadj 1.9, 95% CI: 1.2, 3.0) and sharing a latrine with one household (RRadj 2.1, 95% CI: 1.2, 3.6) or >1 household (RRadj 3.1, 95% CI: 1.8–5.2) were independently associated with increased risk of secondary ILI. Conclusion Tobacco use in homes could increase respiratory illness in Bangladesh. The mechanism between use of shared latrines and household ILI transmission is not clear. It is possible that respiratory pathogens could be transmitted through faecal contact or contaminated fomites in shared latrines.
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Affiliation(s)
- Anne M Weaver
- School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA.,Richard M. Fairbanks School of Public Health, Indiana University, Indianapolis, IN, USA
| | | | - Emily Cercone
- School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA
| | - Kimberly Krytus
- School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA
| | - Badrul Munir Sohel
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Makhdum Ahmed
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Mustafizur Rahman
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Jihnhee Yu
- School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA
| | - Alicia M Fry
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stephen P Luby
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.,Stanford University, Stanford, CA, USA
| | - Pavani K Ram
- School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA
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249
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Kalliomäki P, Saarinen P, Tang JW, Koskela H. Airflow patterns through single hinged and sliding doors in hospital isolation rooms - Effect of ventilation, flow differential and passage. BUILDING AND ENVIRONMENT 2016; 107:154-168. [PMID: 32287966 PMCID: PMC7115809 DOI: 10.1016/j.buildenv.2016.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/03/2016] [Accepted: 07/13/2016] [Indexed: 05/22/2023]
Abstract
Negative pressure isolation rooms are used to house patients with highly contagious diseases (e.g. with airborne diseases) and to contain emitted pathogens to reduce the risk for cross-infection in hospitals. Airflows induced by door opening motion and healthcare worker passage can, however, transport the potentially pathogen laden air across the doorway. In this study airflow patterns across the isolation room doorway induced by the operation of single hinged and sliding doors with simulated human passage were examined. Smoke visualizations demonstrated that the hinged door opening generated a greater flow across the doorway than the sliding door. Tracer gas measurements showed that the examined ventilation rates (6 and 12 air changes per hour) had only a small effect on the air volume exchange across the doorway with the hinged door. The results were more variable with the sliding door. Supply-exhaust flow rate differential reduced the door motion-induced air transfer significantly with both door types. The experiments showed that the passage induced substantial air volume transport through the doorway with both door types. However, overall, the sliding door performed better in all tested scenarios, because the door-opening motion itself generated relatively smaller air volume exchange across the doorway, and hence should be the preferred choice in the design of isolation rooms.
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Affiliation(s)
- Petri Kalliomäki
- Finnish Institute of Occupational Health, Lemminkäisenkatu 14 – 18 B, 20520 Turku, Finland
- Turku University of Applied Sciences, Lemminkäisenkatu 14 – 18 B, 20520 Turku, Finland
| | - Pekka Saarinen
- Finnish Institute of Occupational Health, Lemminkäisenkatu 14 – 18 B, 20520 Turku, Finland
- Turku University of Applied Sciences, Lemminkäisenkatu 14 – 18 B, 20520 Turku, Finland
| | - Julian W. Tang
- Clinical Microbiology, University Hospitals of Leicester, United Kingdom
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Hannu Koskela
- Finnish Institute of Occupational Health, Lemminkäisenkatu 14 – 18 B, 20520 Turku, Finland
- Turku University of Applied Sciences, Lemminkäisenkatu 14 – 18 B, 20520 Turku, Finland
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Mirhoseini SH, Nikaeen M, Khanahmad H, Hassanzadeh A. Occurrence of airborne vancomycin- and gentamicin-resistant bacteria in various hospital wards in Isfahan, Iran. Adv Biomed Res 2016; 5:143. [PMID: 27656612 PMCID: PMC5025915 DOI: 10.4103/2277-9175.187399] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 01/06/2016] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Airborne transmission of pathogenic resistant bacteria is well recognized as an important route for the acquisition of a wide range of nosocomial infections in hospitals. The aim of this study was to determine the prevalence of airborne vancomycin and gentamicin (VM and GM) resistant bacteria in different wards of four educational hospitals. MATERIALS AND METHODS A total of 64 air samples were collected from operating theater (OT), Intensive Care Unit (ICU), surgery ward, and internal medicine ward of four educational hospitals in Isfahan, Iran. Airborne culturable bacteria were collected using all glass impingers. Samples were analyzed for the detection of VM- and GM-resistant bacteria. RESULTS The average level of bacteria ranged from 99 to 1079 CFU/m(3). The highest level of airborne bacteria was observed in hospital 4 (628 CFU/m(3)) and the highest average concentration of GM- and VM-resistant airborne bacteria were found in hospital 3 (22 CFU/m(3)). The mean concentration of airborne bacteria was the lowest in OT wards and GM- and VM-resistant airborne bacteria were not detected in this ward of hospitals. The highest prevalence of antibiotic-resistant airborne bacteria was observed in ICU ward. There was a statistically significant difference for the prevalence of VM-resistant bacteria between hospital wards (P = 0.012). CONCLUSION Our finding showed that the relatively high prevalence of VM- and GM-resistant airborne bacteria in ICUs could be a great concern from the point of view of patients' health. These results confirm the necessity of application of effective control measures which significantly decrease the exposure of high-risk patients to potentially airborne nosocomial infections.
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Affiliation(s)
- Seyed Hamed Mirhoseini
- Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahnaz Nikaeen
- Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hossein Khanahmad
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Akbar Hassanzadeh
- Department of Statistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
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