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Reinhardt ÉL. Transmissão da COVID-19: um breve reexame das vias de transmissão por gotículas e aerossóis. REVISTA BRASILEIRA DE SAÚDE OCUPACIONAL 2022. [DOI: 10.1590/2317-6369000000221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Resumo O rápido desenrolar da pandemia de COVID-19 no ano de 2020 estimulou pesquisadores a rapidamente tentar entender o comportamento do vírus e da doença e a propor soluções de modo a tentar contê-la o quanto antes. Uma das questões fundamentais a serem respondidas é se o vírus também pode ser transmitido por aerossóis, posto que a forma de transmissão determina a velocidade e as condições em que a doença consegue se espalhar pela população. A busca por essa resposta reacendeu uma discussão de décadas sobre a relevância dessa via de transmissão, bem como sobre os diferentes conceitos e medidas de controle e prevenção atualmente usados para bloquear a transmissão de doenças infecciosas no âmbito da atenção à saúde humana. Este ensaio tem o objetivo de contribuir para esse debate e, mais especificamente, subsidiar programas para a proteção de trabalhadores e pacientes em serviços de saúde referentes à COVID-19 e a outras doenças infecciosas.
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Affiliation(s)
- Érica Lui Reinhardt
- Fundação Jorge Duprat Figueiredo de Segurança e Medicina do Trabalho, Brasil
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Mather MW, Jardine L, Talks B, Gardner L, Haniffa M. Complexity of immune responses in COVID-19. Semin Immunol 2021; 55:101545. [PMID: 34865933 PMCID: PMC8626289 DOI: 10.1016/j.smim.2021.101545] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 12/15/2022]
Abstract
The global COVID-19 pandemic has caused substantial morbidity and mortality to humanity. Remarkable progress has been made in understanding both the innate and adaptive mechanisms involved in the host response to the causative SARS-CoV-2 virus, but much remains to be discovered. Robust upper airway defenses are critical in restricting SARS-CoV-2 replication and propagation. Further, the nasal abundance of viral uptake receptor, ACE2, and the host epithelial transcriptional landscape, are associated with differential disease outcomes across different patient cohorts. The adaptive host response to systemic COVID-19 is heterogeneous and complex. Blunted responses to interferon and robust cytokine generation are hallmarks of the disease, particularly at the advanced stages. Excessive immune cell influx into tissues can lead to substantial collateral damage to the host akin to sepsis. This review offers a contemporary summary of these mechanisms of disease and highlights potential avenues for diagnostic and therapeutic development. These include improved disease stratification, targeting effectors of immune-mediated tissue damage, and blunting of immune cell-mediated tissue damage.
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Affiliation(s)
- Michael William Mather
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK; Department of Otolaryngology, Freeman Hospital, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, NE7 7DN, UK
| | - Laura Jardine
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK; Haematology Department, Freeman Hospital, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, NE7 7DN, UK
| | - Ben Talks
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK; Department of Otolaryngology, Freeman Hospital, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, NE7 7DN, UK
| | - Louis Gardner
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK; Department of Dermatology and NIHR Newcastle Biomedical Research Centre, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE2 4LP, UK
| | - Muzlifah Haniffa
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK; Department of Dermatology and NIHR Newcastle Biomedical Research Centre, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE2 4LP, UK; Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
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Rivera-Sepúlveda A, García-Rivera E, Castro M, Soto F. Risk Factors Associated With Bronchiolitis in Puerto Rican Children. Pediatr Emerg Care 2021; 37:e1593-e1599. [PMID: 32530834 PMCID: PMC7728621 DOI: 10.1097/pec.0000000000002130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The objective of this study was to identify frequency, severity, and risk factors associated with bronchiolitis in Puerto Rican children. METHODS A cross-sectional was study performed at 4 emergency departments of Puerto Rico's metropolitan area, between June 2014 and May 2015. We included children younger than 24 months, with a clinical diagnosis of bronchiolitis, who were born and living in Puerto Rico at the time of recruitment. A physician-administered questionnaire inquiring about the patient's medical, family, and social history and a bronchiolitis severity assessment were performed. Daily weather conditions were monitored, and aeroallergens were collected with an air sample and precision weather station within the metropolitan area to evaluate environmental factors. RESULTS We included 600 patients for 12 months. More than 50% of the recruited patients had a previous episode of bronchiolitis, of which 40% had been hospitalized. Older age (odds ratio [OR], 18.3; 95% confidence interval [CI], 9.2-36.5), male sex (OR, 1.6; 95% CI, 1.1-2.4), history of asthma (OR, 8.9; 95% CI, 3.6-22), allergic rhinitis (OR, 3.6; 95% CI, 1.8-7.4), and smoke exposure by a caretaker (OR, 2.3; 95% CI, 1.2-4.4) were predictors of bronchiolitis episodes. Bronchiolitis episodes were associated with higher severity score (P = 0.040), increased number of atopic factors (P < 0.001), and higher number of hospitalizations (P < 0.001). CONCLUSIONS This study identifies Puerto Rican children who may present a severe clinical course of disease without traditional risk factors. Atopy-related factors are associated with frequency and severity of bronchiolitis. Puerto Rican children present risk factors related to atopy earlier in life, some of which may be modified to prevent the subsequent development of asthma.
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Affiliation(s)
| | | | - Mario Castro
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St Louis, MO
| | - Fernando Soto
- Department of Emergency Medicine, School of Medicine, Medical Sciences Campus, University of Puerto Rico, San Juan, Puerto Rico
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Büchner F, Hoffman M, Dobermann UH, Edel B, Lehmann T, Kipp F. Do closed waste containers lead to less air contamination than opened? A clinical case study at Jena University Hospital, Germany. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 136:11-17. [PMID: 34634566 DOI: 10.1016/j.wasman.2021.09.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 09/13/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
Nosocomial infections are a growing challenge at hospitals. This clinical study aimed to investigate the influence of waste container construction ((open (O), closed (C), and hands-free opening (HF)) on microbial air contamination in a hospital setting. The results are intended to help develop guidelines for waste containers for the collection of non-infectious waste at hospitals and medical facilities. The clinical experiment was conducted at the University Hospital Jena, Germany. Air Impactor samples were performed and microbiologically evaluated for bacteria and fungi both quantitatively and qualitatively. The results were statistically determined using generalized estimating equations. Quantitatively, the lowest bacterial counts in ambient air were found around closed waste containers (114.74 CFU/m3) in comparison to HF (129.28 CFU/m3) and O (126.28 CFU/m3). For fungi, the surrounding air of C (2.08 CFU/m3) and HF (1.97 CFU/m3) waste containers showed a lower impact of fungal air contamination than for O (2.32 CFU/m3). Overall, it was shown that C are more preferable to HF and O waste containers from the point of view of microbial air contamination at hospitals.
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Affiliation(s)
- Franziskus Büchner
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany.
| | - Marc Hoffman
- Integrative Health and Security Management Center, Staff Section Environmental Protection, Jena University Hospital, Bachstraße 18, D-07743 Jena, Germany
| | - Ute-Helke Dobermann
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany
| | - Birgit Edel
- Institute of Medical Microbiology, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany
| | - Thomas Lehmann
- Institute of Medical Statistics, Computer and Data Sciences, Jena University Hospital, Bachstraße 18, D-07743 Jena, Germany
| | - Frank Kipp
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany
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Quraishi N, Ray M, Srivastava R, Ray J, Quraishi MS. A multicentre retrospective cohort study on COVID-19-related physical interventions and adult hospital admissions for ENT infections. Eur Arch Otorhinolaryngol 2021; 279:2671-2678. [PMID: 34807284 PMCID: PMC8607061 DOI: 10.1007/s00405-021-07180-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/06/2021] [Indexed: 02/06/2023]
Abstract
Purpose To report changes in adult hospital admission rates for acute ENT infections following the introduction of COVID-19-related physical interventions such as hand washing, use of face masks and social distancing of 2-m in the United Kingdom. Methods Retrospective cohort study comparing adult admissions with acute tonsillitis, peritonsillar abscess, epiglottitis, glandular fever, peri-orbital cellulitis, acute otitis media, acute mastoiditis, retropharyngeal abscess and parapharyngeal abscess in the 1-year period after the introduction of COVID-related physical interventions (2020–2021) with a 1-year period before this (2019–2020) in three UK secondary care ENT departments. Results In total, there were significantly fewer admissions for ENT infections (n = 1073, 57.56%, p < 0.001; RR 2.36, 95% CI [2.17, 2.56]) in the 2020–2021 period than in the 2019–2020 period. There were significant reductions in admissions for tonsillitis (64.4%; p < 0.001), peritonsillar abscess (60.68%; p < 0.001), epiglottitis (66.67%; p < 0.001), glandular fever (38.79%; p = 0.001), acute otitis media (26.85%; p = 0.01) and retropharyngeal and/or parapharyngeal abscesses (45.45%; p = 0.04). Conclusion Our study demonstrates a sizeable reduction in adult admissions for ENT infections since the introduction of COVID-19-related physical interventions. There is evidence to support the use of physical interventions in the prevention of viral transmission of respiratory disease. Preventing ENT infections requiring admission through simple physical interventions could be of great benefit to the quality of life of patients and economical benefit to healthcare systems.
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Affiliation(s)
| | | | | | - Jaydip Ray
- Sheffield Teaching Hospitals, Sheffield, UK
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Baldan M, Manente S, Izzo FC. The role of bio-pollutants in the indoor air quality of old museum buildings: artworks biodeterioration as preview of human diseases. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:787. [PMID: 34757536 DOI: 10.1007/s10661-021-09568-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 10/26/2021] [Indexed: 06/13/2023]
Abstract
Indoor air quality in buildings is strongly affected by chemical, physical, and biological agents. Long exposure to inadequate indoor air quality can be very dangerous for the building occupants and can lead to chronic diseases associated with the sick building syndrome (SBS). In this paper, the large presence of biological pollutants in the indoor rooms of an old building and its strict relationship with the outdoor/indoor air conditions were investigated studying Coronini Cronberg Palace Foundation, a historic house museum of the sixteenth century in Gorizia (Italy), where biological contamination affecting the artworks can soon become potentially harmful also for operators and visitors. Detailed aerobiological and microbiological analyses on organic natural materials, combined with a microclimate monitoring, were conducted to evaluate the influence of temperature and relative humidity levels within the Palace in the conspicuous growth and diffusion of microorganisms. Fungal and bacterial colonies damaging materials, mainly affected by the sudden fluctuations of hygrothermal values, were found to widely exceed Italian and international recommended levels for good air quality for both artworks and human beings. Understand their impact on human health would be strictly necessary to reduce biological risks for museum staff and cultural heritage users, but consequently to improve indoor air quality.
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Affiliation(s)
- Maela Baldan
- Environmental Sciences, Informatics and Statistics (DAIS), Ca' Foscari University of Venice, Scientific Campus, Via Torino 155, Venice-Mestre, 30170, Italy
| | - Sabrina Manente
- Molecular Sciences and Nanosystems Dept. (DSMN), Ca' Foscari University of Venice, Scientific Campus, via Torino 155, Venice-Mestre, 30170, Italy.
| | - Francesca Caterina Izzo
- Environmental Sciences, Informatics and Statistics (DAIS), Ca' Foscari University of Venice, Scientific Campus, Via Torino 155, Venice-Mestre, 30170, Italy
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Ahmadi Y, Bhardwaj N, Kim KH, Kumar S. Recent advances in photocatalytic removal of airborne pathogens in air. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148477. [PMID: 34198079 DOI: 10.1016/j.scitotenv.2021.148477] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/31/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
The abatement of airborne pathogens such as bacteria, viruses, and fungi has become an important goal of air-quality management. Efficient and effective treatment techniques such as photocatalysis are essential for disinfection of airborne microorganisms. This review focuses on recent advances in the formulation and development of photocatalytic disinfection, design of efficient photocatalysts, choice of photocatalytic reactor, removal and/or disinfection mechanisms, and the role of reactive ion species. Data from recent studies are analyzed to accurately assess the efficacy of such disinfection approaches. This review also highlights the application of innovative materials in individual and combined abatement systems against airborne bacterial, viral, and fungal pathogens. We discuss the efficiency and benefits presented by such systems, address the challenges, and provide a perspective for future research.
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Affiliation(s)
- Younes Ahmadi
- Department of Analytical Chemistry, Kabul University, Kabul 1001, Afghanistan
| | - Neha Bhardwaj
- Department of Biotechnology, University Institute of Engineering Technology (UIET), Panjab University, Chandigarh, India
| | - Ki-Hyun Kim
- Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea.
| | - Sandeep Kumar
- Department of Bio and Nano Technology, Guru Jambheshwar University of Science and Technology, Hisar, Haryana 125001, India.
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Yonenaga K, Itai S, Hoshi K. Implications for clinical dental practice during the coronavirus disease pandemic: A scoping review. J Prosthodont Res 2021; 66:6-11. [PMID: 34707074 DOI: 10.2186/jpr.jpr_d_21_00064] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE It is over a year since the first case of coronavirus disease (COVID-19) was confirmed in China. This paper reviews and summarizes the characteristics of COVID-19, as understood of December 2020, from a dental perspective. STUDY SELECTION The PubMed and Scopus online databases were searched using a combination of free words and Medical Subject Headings terms: "dentist" OR "oral care" AND "COVID-19" OR "SARS-CoV-2." RESULTS Older people and those with underlying medical conditions have an increased risk of serious illness due to COVID-19. The virus enters the body by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. It is common for people with COVID-19 to have mild or no symptoms. Moreover, the disease is not contagious in most infected people; it is only highly contagious in some infected people, thereby forming clusters. Due to the large number of virus particles that are shed prior to the onset of symptoms of the disease, retrospective surveys are important. Appropriate personal protective equipment against corona vortices is also important in clinical practice. Although polymerase chain reaction tests are useful for confirming infection in suspected individuals, their reliability is questionable. In addition, concerns regarding long-term sequelae have been reported. CONCLUSIONS There are few high-quality reports on the implications of COVID-19 in dental practice. However, reports suggest that insufficient oral hygiene may be a risk factor for infection. Reports that ACE2 receptors are abundant in the oral cavity also suggest the importance of oral care.
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Affiliation(s)
- Kazumichi Yonenaga
- Department of Eat-Loss Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Oral-maxillofacial Surgery, Dentistry and Orthodontics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shunsuke Itai
- Department of Eat-Loss Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Oral-maxillofacial Surgery, Dentistry and Orthodontics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kazuto Hoshi
- Department of Oral-maxillofacial Surgery, Dentistry and Orthodontics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Microdebrider is less aerosol-generating than CO 2 laser and cold instruments in microlaryngoscopy. Eur Arch Otorhinolaryngol 2021; 279:825-834. [PMID: 34623498 PMCID: PMC8498765 DOI: 10.1007/s00405-021-07105-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/20/2021] [Indexed: 11/15/2022]
Abstract
Objective COVID-19 spreads through aerosols produced in coughing, talking, exhalation, and also in some surgical procedures. Use of CO2 laser in laryngeal surgery has been observed to generate aerosols, however, other techniques, such cold dissection and microdebrider, have not been sufficiently investigated. We aimed to assess whether aerosol generation occurs during laryngeal operations and the effect of different instruments on aerosol production. Methods We measured particle concentration generated during surgeries with an Optical Particle Sizer. Cough data collected from volunteers and aerosol concentration of an empty operating room served as references. Aerosol concentrations when using different techniques and equipment were compared with references as well as with each other. Results Thirteen laryngological surgeries were evaluated. The highest total aerosol concentrations were observed when using CO2 laser and these were significantly higher than the concentrations when using microdebrider or cold dissection (p < 0.0001, p < 0.0001) or in the background or during coughing (p < 0.0001, p < 0.0001). In contrast, neither microdebrider nor cold dissection produced significant concentrations of aerosol compared with coughing (p = 0.146, p = 0.753). In comparing all three techniques, microdebrider produced the least aerosol particles. Conclusions Microdebrider and cold dissection can be regarded as aerosol-generating relative to background reference concentrations, but they should not be considered as high-risk aerosol-generating procedures, as the concentrations are low and do not exceed those of coughing. A step-down algorithm from CO2 laser to cold instruments and microdebrider is recommended to lower the risk of airborne infections among medical staff.
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Matta I, Laganà AS, Ghabi E, Bitar L, Ayed A, Petousis S, Vitale SG, Sleiman Z. COVID-19 transmission in surgical smoke during laparoscopy and open surgery: a systematic review. MINIM INVASIV THER 2021; 31:690-697. [PMID: 34612141 DOI: 10.1080/13645706.2021.1982728] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM To evaluate the risk of SARS-CoV-2 transmission in surgical smoke and aerosols during laparoscopy and open surgery. MATERIAL AND METHODS A systematic review (PROSPERO ID: CRD42021268366) was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were selected based on the title and abstract as well as the type of publication. Primary objectives of the study were to assess potential risk of contamination as well as comparing laparoscopic and open procedures in terms of danger of SARS-COV-2 transmission. RESULTS Fifty-three articles were identified and included in the review. No case of SARS-CoV-2 transmission to operating room personnel during open or minimally invasive surgery was identified at the time the review was conducted. Furthermore, no significant difference was observed between smoke and aerosols generated from open surgery and those generated from minimally invasive surgery. CONCLUSION COVID-19 transmission in surgical smoke and aerosols has yet to be observed. However, given the potential risk of viral transmission, caution should be exercised when performing surgery to ensure the safety of the operating room personnel. When clinically indicated and when protective measures can be implemented, minimally invasive surgery should be performed instead of open surgery to ensure optimal patient outcomes.
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Affiliation(s)
- Imad Matta
- Division of Urology, University of Balamand, Beirut, Lebanon
| | - Antonio Simone Laganà
- Department of Obstetrics and Gynecology, "Filippo Del Ponte" Hospital, University of Insubria, Varese, Italy
| | - Elie Ghabi
- Division of Urology, University of Balamand, Beirut, Lebanon
| | - Lynn Bitar
- Saint Joseph University, Beirut, Lebanon
| | - Amal Ayed
- Department of Obstetrics and Gynecology, Farwanya Hospital, MOH, Farwanya, Kuwait
| | - Stamatios Petousis
- 2nd Department of Obstetrics and Gynecology, Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, Ippokratio General Hospital, Thessaloniki, Greece
| | - Salvatore Giovanni Vitale
- Obstetrics and Gynecology Unit, Department of General Surgery and Medical Surgical Specialties, University of Catania, Catania, Italy
| | - Zaki Sleiman
- Department of Obstetrics and Gynecology, Lebanese American University, Beirut, Lebanon
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Toyokawa T, Shimada T, Hayamizu T, Sekizuka T, Zukeyama Y, Yasuda M, Nakamura Y, Okano S, Kudaka J, Kakita T, Kuroda M, Nakasone T. Transmission of SARS-CoV-2 during a 2-h domestic flight to Okinawa, Japan, March 2020. Influenza Other Respir Viruses 2021; 16:63-71. [PMID: 34605181 PMCID: PMC8652895 DOI: 10.1111/irv.12913] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 01/02/2023] Open
Abstract
Background Coronavirus disease (COVID‐19), caused by severe acute respiratory syndrome coronavirus (SARS‐CoV‐2), has rapidly spread globally. Potentially infected individuals travel on commercial aircraft. Thus, this study aimed to investigate and test the association between the use of face masks, physical distance, and COVID‐19 among passengers and flight attendants exposed to a COVID‐19 passenger in a domestic flight. Methods This observational study investigated passengers and flight attendants exposed to COVID‐19 on March 23, 2020, on board a flight to Naha City, Japan. Secondary attack rates were calculated. Whole‐genome sequencing of SARS‐CoV‐2 was used to identify the infectious linkage between confirmed cases in this clustering. The association between confirmed COVID‐19 and proximity of passengers' seats to the index case and/or the use of face masks was estimated using logistic regression. Results Fourteen confirmed and six probable cases were identified among passengers and flight attendants. The secondary attack rate was 9.7%. Twelve of 14 SARS‐CoV‐2 genome sequences in confirmed cases were identical to that of the index case or showed only one nucleotide mutation. Risk factors for infection included not using a face mask (adjusted odds ratio [aOR]: 7.29, 95% confidence interval [95% CI]: 1.86‐28.6), partial face mask use (aOR: 3.0, 95% CI: 0.83‐10.8), and being seated within two rows from the index patient (aOR: 7.47, 95% CI: 2.06‐27.2). Conclusion SARS‐CoV‐2 was transmitted on the airplane. Nonuse of face masks was identified as an independent risk factor for contracting COVID‐19 on the airplane.
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Affiliation(s)
- Takao Toyokawa
- COVID-19 Response Team, Naha City Public Health Center, Naha-shi, Okinawa, Japan
| | - Tomoe Shimada
- Infectious Disease Surveillance Center, National Institute of Infectious Diseases (NIID), Shinjuku-ku, Tokyo, Japan
| | - Takahiro Hayamizu
- COVID-19 Response Team, Naha City Public Health Center, Naha-shi, Okinawa, Japan
| | - Tsuyoshi Sekizuka
- Pathogen Genomics Center, National Institute of Infectious Diseases (NIID), Shinjuku-ku, Tokyo, Japan
| | - Yuji Zukeyama
- COVID-19 Response Team, Naha City Public Health Center, Naha-shi, Okinawa, Japan
| | - Miyako Yasuda
- COVID-19 Response Team, Naha City Public Health Center, Naha-shi, Okinawa, Japan
| | - Yuko Nakamura
- COVID-19 Response Team, Naha City Public Health Center, Naha-shi, Okinawa, Japan
| | - Sho Okano
- Regional Health Division, Department of Public Health and Medical Care, Okinawa Prefectural Government, Naha-shi, Okinawa, Japan
| | - Jun Kudaka
- Regional Health Division, Department of Public Health and Medical Care, Okinawa Prefectural Government, Naha-shi, Okinawa, Japan
| | - Tetsuya Kakita
- Okinawa Prefectural Institute of Health and Environment, Uruma-shi, Okinawa, Japan
| | - Makoto Kuroda
- Pathogen Genomics Center, National Institute of Infectious Diseases (NIID), Shinjuku-ku, Tokyo, Japan
| | - Tadashi Nakasone
- COVID-19 Response Team, Naha City Public Health Center, Naha-shi, Okinawa, Japan
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Dabiri D, Conti SR, Sadoughi Pour N, Chong A, Dadjoo S, Dabiri D, Wiese C, Badal J, Hoogland MA, Conti HR, Taylor TR, Choueiri G, Amili O. A Multi-Disciplinary Review on the Aerobiology of COVID-19 in Dental Settings. FRONTIERS IN DENTAL MEDICINE 2021; 2. [PMID: 35574425 PMCID: PMC9098049 DOI: 10.3389/fdmed.2021.726395] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The COVID-19 pandemic pushed dental health officials around the world to reassess and adjust their existing healthcare practices. As studies on controlled COVID-19 transmission remain challenging, this review focuses on particles that can carry the virus and relevant approaches to mitigate the risk of pathogen transmission in dental offices. This review gives an overview of particles generated in clinical settings and how size influences their distribution, concentration, and generation route. A wide array of pertinent particle characterization and counting methods are reviewed, along with their working range, reliability, and limitations. This is followed by a focus on the effectiveness of personal protective equipment (PPE) and face shields in protecting patients and dentists from aerosols. Direct studies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are still limited, but the literature supports the use of masks as an important and effective non-pharmaceutical preventive measure that could reduce the risk of contracting a respiratory infection by up to 20%. In addition to discussing about PPE used by most dental care professionals, this review describes other ways by which dental offices can protect patients and dental office personnel, which includes modification of the existing room design, dental equipment, and heating, ventilation, and air conditioning (HVAC) system. More affordable modifications include positioning a high-efficiency particulate air (HEPA) unit within proximity of the patient’s chair or using ultraviolet germicidal irradiation in conjunction with ventilation. Additionally, portable fans could be used to direct airflow in one direction, first through the staff working areas and then through the patient treatment areas, which could decrease the number of airborne particles in dental offices. This review concludes that there is a need for greater awareness amongst dental practitioners about the relationship between particle dynamics and clinical dentistry, and additional research is needed to fill the broad gaps of knowledge in this field.
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Affiliation(s)
- Darya Dabiri
- Department of Dentistry, Division of Pediatric Dentistry, University of Toledo, Toledo, OH, United States
- Correspondence: Darya Dabiri,
| | - Samuel Richard Conti
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - Niloufar Sadoughi Pour
- Department of Mechanical, Industrial and Manufacturing Engineering (MIME), University of Toledo, Toledo, OH, United States
| | - Andrew Chong
- Department of Cariology, Restorative Sciences & Endodontics, University of Michigan, Ann Arbor, MI, United States
| | - Shaahin Dadjoo
- Department of Orthodontics and Dentofacial Orthopedics, The Eastman Institute for Oral Health, University of Rochester, Rochester, NY, United States
| | - Donya Dabiri
- Department of Dentistry, Division of Pediatric Dentistry, University of Toledo, Toledo, OH, United States
| | - Carol Wiese
- Department of Dentistry, Division of Pediatric Dentistry, University of Toledo, Toledo, OH, United States
| | - Joyce Badal
- Department of Medicine, University of Toledo, Toledo, OH, United States
| | | | - Heather Raquel Conti
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - Travis Roger Taylor
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, United States
| | - George Choueiri
- Department of Mechanical, Industrial and Manufacturing Engineering (MIME), University of Toledo, Toledo, OH, United States
| | - Omid Amili
- Department of Mechanical, Industrial and Manufacturing Engineering (MIME), University of Toledo, Toledo, OH, United States
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Matuka DO, Duba T, Ngcobo Z, Made F, Muleba L, Nthoke T, Singh TS. Occupational Risk of Airborne Mycobacterium tuberculosis Exposure: A Situational Analysis in a Three-Tier Public Healthcare System in South Africa. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph181910130. [PMID: 34639431 PMCID: PMC8508202 DOI: 10.3390/ijerph181910130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/15/2021] [Accepted: 09/18/2021] [Indexed: 11/23/2022]
Abstract
This study aimed to detect airborne Mycobacterium tuberculosis (MTB) at nine public health facilities in three provinces of South Africa and determine possible risk factors that may contribute to airborne transmission. Personal samples (n = 264) and stationary samples (n = 327) were collected from perceived high-risk areas in district, primary health clinics (PHCs) and TB facilities. Quantitative real-time (RT) polymerase chain reaction (PCR) was used for TB analysis. Walkabout observations and work practices through the infection prevention and control (IPC) questionnaire were documented. Statistical analysis was carried out using Stata version 15.2 software. Airborne MTB was detected in 2.2% of samples (13/572), and 97.8% were negative. District hospitals and Western Cape province had the most TB-positive samples and identified risk areas included medical wards, casualty, and TB wards. MTB-positive samples were not detected in PHCs and during the summer season. All facilities reported training healthcare workers (HCWs) on TB IPC. The risk factors for airborne MTB included province, type of facility, area or section, season, lack of UVGI, and ineffective ventilation. Environmental monitoring, PCR, IPC questionnaire, and walkabout observations can estimate the risk of TB transmission in various settings. These findings can be used to inform management and staff to improve the TB IPC programmes.
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Affiliation(s)
- Dikeledi O. Matuka
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Thabang Duba
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Zethembiso Ngcobo
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Felix Made
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Lufuno Muleba
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Tebogo Nthoke
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Tanusha S. Singh
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
- Department of Clinical Microbiology and Infectious Disease, School of Pathology, University of the Witwatersrand, Johannesburg 2000, South Africa
- Department of Environmental Health, School of Health Sciences, University of Johannesburg, Johannesburg 2028, South Africa
- Correspondence:
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Sobolik JS, Sajewski ET, Jaykus LA, Cooper DK, Lopman BA, Kraay ANM, Ryan PB, Guest JL, Webb-Girard A, Leon JS. Low risk of SARS-CoV-2 transmission via fomite, even in cold-chain. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2021:2021.08.23.21262477. [PMID: 34462753 PMCID: PMC8404890 DOI: 10.1101/2021.08.23.21262477] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Countries continue to debate the need for decontamination of cold-chain food packaging to reduce possible SARS-CoV-2 fomite transmission among workers. While laboratory-based studies demonstrate persistence of SARS-CoV-2 on surfaces, the likelihood of fomite-mediated transmission under real-life conditions is uncertain. METHODS Using a quantitative risk assessment model, we simulated in a frozen food packaging facility 1) SARS-CoV-2 fomite-mediated infection risks following worker exposure to contaminated plastic packaging; and 2) reductions in these risks attributed to masking, handwashing, and vaccination. FINDINGS In a representative facility with no specific interventions, SARS-CoV-2 infection risk to a susceptible worker from contact with contaminated packaging was 2·8 × 10 -3 per 1h-period (95%CI: 6·9 × 10 -6 , 2·4 × 10 -2 ). Implementation of standard infection control measures, handwashing and masks (9·4 × 10 -6 risk per 1h-period, 95%CI: 2·3 × 10 -8 , 8·1 × 10 -5 ), substantially reduced risk (99·7%). Vaccination of the susceptible worker (two doses Pfizer/Moderna, vaccine effectiveness: 86-99%) combined with handwashing and masking reduced risk to less than 1·0 × 10 -6 . Simulating increased infectiousness/transmissibility of new variants (2-, 10-fold viral shedding) among a fully vaccinated workforce, handwashing and masks continued to mitigate risk (2·0 × 10 -6 -1·1 × 10 -5 risk per 1h-period). Decontamination of packaging in addition to these interventions reduced infection risks to below the 1·0 × 10 -6 risk threshold. INTERPRETATION Fomite-mediated SARS-CoV-2 infection risks were very low under cold-chain conditions. Handwashing and masking provide significant protection to workers, especially when paired with vaccination. FUNDING U.S. Department of Agriculture.
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Affiliation(s)
- Julia S. Sobolik
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
| | | | - Lee-Ann Jaykus
- Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, USA, 27695
| | - D. Kane Cooper
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
| | - Ben A. Lopman
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
| | - Alicia NM. Kraay
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
| | - P. Barry Ryan
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
| | - Jodie L. Guest
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
| | - Amy Webb-Girard
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
| | - Juan S. Leon
- Rollins School of Public Health, Emory University, Atlanta, GA, USA, 30322
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Radney JG, Weaver JL, Vicenzi EP, Staymates ME, Zangmeister CD. Filter Inserts Impact Cloth Mask Performance against Nano- to Micro-Sized Particles. ACS NANO 2021; 15:12860-12868. [PMID: 34251793 DOI: 10.1021/acsnano.1c05182] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The United States Centers for Disease Control and Prevention and World Health Organization recognize that wearing cloth face coverings can slow the transmission of respiratory diseases via source control. Adding a partial layer of material with a high filtration efficiency (FE, e.g., polypropylene sheets that meet the HEPA standard) as an insert can potentially provide additional personal protection; however, data on the necessary areal coverage are sparse. The relationship between insert area ratio (IAR) relative to fabric area, FE, differential pressure (ΔP, a surrogate for breathability), and quality factor (QF, a ratio including FE and ΔP) utilizing two fabrics (rayon and 100% cotton lightweight flannel) and three insert materials (HEPA vacuum bag, sterilization wrap and paper coffee filter) was investigated. The effect of inserts on particle flows mimicking human exhalation is semiquantitatively and qualitatively examined using flow visualization techniques. The following was found: (1) The relationship between FE, ΔP, and QF is complex, and a trade-off exists between personal protection from filtration during inhalation and source control from leakage during exhalation; (2) FE and ΔP of the composite covering increase with IAR, and the rate is dependent upon insert type; (3) improvements (decrements) in the QF of the composite assemblage require inserts with a higher (lower) QF than the fabric and larger differences yield greater gains (losses); (4) the increased ΔP from an insert results in increased leakage during exhalation; (5) to minimize leaks, ΔP must be as low as possible; and (6) small relative areas not covered by an insert (i.e., IAR slightly smaller than 1) strongly deteriorate the benefits of an insert similar to small leaks in a covering.
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Affiliation(s)
- James G Radney
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jamie L Weaver
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Museum Conservation Institute, Smithsonian Institution, Suitland, Maryland 20746, United States
| | - Edward P Vicenzi
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Museum Conservation Institute, Smithsonian Institution, Suitland, Maryland 20746, United States
| | - Matthew E Staymates
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Christopher D Zangmeister
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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Moritz S, Gottschick C, Horn J, Popp M, Langer S, Klee B, Purschke O, Gekle M, Ihling A, Zimmermann FDL, Mikolajczyk R. The risk of indoor sports and culture events for the transmission of COVID-19. Nat Commun 2021; 12:5096. [PMID: 34413294 DOI: 10.1101/2020.10.28.20221580] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 08/03/2021] [Indexed: 05/22/2023] Open
Abstract
Nearly all mass gathering events worldwide were banned at the beginning of the COVID-19 pandemic, as they were suspected of presenting a considerable risk for the transmission of SARS-CoV-2. We investigated the risk of transmitting SARS-CoV-2 by droplets and aerosols during an experimental indoor mass gathering event under three different hygiene practices, and used the data in a simulation study to estimate the resulting burden of disease under conditions of controlled epidemics. Our results show that the mean number of measured direct contacts per visitor was nine persons and this can be reduced substantially by appropriate hygiene practices. A comparison of two versions of ventilation with different air exchange rates and different airflows found that the system which performed worst allowed a ten-fold increase in the number of individuals exposed to infectious aerosols. The overall burden of infections resulting from indoor mass gatherings depends largely on the quality of the ventilation system and the hygiene practices. Presuming an effective ventilation system, indoor mass gathering events with suitable hygiene practices have a very small, if any, effect on epidemic spread.
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Affiliation(s)
- Stefan Moritz
- Section of Clinical Infectious Diseases, University Hospital Halle (Saale), Halle, Germany.
| | - Cornelia Gottschick
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Johannes Horn
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Mario Popp
- Section of Clinical Infectious Diseases, University Hospital Halle (Saale), Halle, Germany
| | - Susan Langer
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Bianca Klee
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Oliver Purschke
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Michael Gekle
- Julius Bernstein-Institute of Physiology, Faculty of Medicine, Martin Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Angelika Ihling
- Section of Clinical Infectious Diseases, University Hospital Halle (Saale), Halle, Germany
| | | | - Rafael Mikolajczyk
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
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Moritz S, Gottschick C, Horn J, Popp M, Langer S, Klee B, Purschke O, Gekle M, Ihling A, Zimmermann FDL, Mikolajczyk R. The risk of indoor sports and culture events for the transmission of COVID-19. Nat Commun 2021; 12:5096. [PMID: 34413294 PMCID: PMC8376924 DOI: 10.1038/s41467-021-25317-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 08/03/2021] [Indexed: 01/04/2023] Open
Abstract
Nearly all mass gathering events worldwide were banned at the beginning of the COVID-19 pandemic, as they were suspected of presenting a considerable risk for the transmission of SARS-CoV-2. We investigated the risk of transmitting SARS-CoV-2 by droplets and aerosols during an experimental indoor mass gathering event under three different hygiene practices, and used the data in a simulation study to estimate the resulting burden of disease under conditions of controlled epidemics. Our results show that the mean number of measured direct contacts per visitor was nine persons and this can be reduced substantially by appropriate hygiene practices. A comparison of two versions of ventilation with different air exchange rates and different airflows found that the system which performed worst allowed a ten-fold increase in the number of individuals exposed to infectious aerosols. The overall burden of infections resulting from indoor mass gatherings depends largely on the quality of the ventilation system and the hygiene practices. Presuming an effective ventilation system, indoor mass gathering events with suitable hygiene practices have a very small, if any, effect on epidemic spread.
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Affiliation(s)
- Stefan Moritz
- Section of Clinical Infectious Diseases, University Hospital Halle (Saale), Halle, Germany.
| | - Cornelia Gottschick
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Johannes Horn
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Mario Popp
- Section of Clinical Infectious Diseases, University Hospital Halle (Saale), Halle, Germany
| | - Susan Langer
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Bianca Klee
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Oliver Purschke
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Michael Gekle
- Julius Bernstein-Institute of Physiology, Faculty of Medicine, Martin Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Angelika Ihling
- Section of Clinical Infectious Diseases, University Hospital Halle (Saale), Halle, Germany
| | | | - Rafael Mikolajczyk
- Institute for Medical Epidemiology, Biometry and Informatics, PZG, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
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68
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Plettenberg C, Geipel K, Stenin I, Klenzner T, Wagenmann M, Schipper J, Scheckenbach K. [Droplet exposure during tracheotomy : Case analysis and consequences with respect to COVID-19 patients]. HNO 2021; 69:650-657. [PMID: 33852060 PMCID: PMC8044664 DOI: 10.1007/s00106-021-01050-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2021] [Indexed: 01/25/2023]
Abstract
BACKGROUND The COVID(coronavirus disease)-19 pandemic is characterized by high infectivity, droplet transmission, and high viral load in the upper respiratory tract. Severe disease courses are associated with interstitial pneumonia and ventilated patients, in whom tracheotomy (TT)-a droplet- and aerosol-producing medical intervention-is regularly necessary. TT as a potential infection risk for medical staff is scarcely found in the literature. Therefore, the aim of this study was to quantify droplet exposure of the surgical team during TT, to better define the requirements for personal protective equipment (PPE). MATERIALS AND METHODS Surgical TT was performed in four non-infectious patients, during which the surgeon and his assistant both wore a surgical nasal mask with a transparent visor. After the procedure, the type, distribution, and number of droplets on the visor were determined macroscopically and microscopically. RESULTS An average of 29 droplets were found on the middle third of the visor, 4 on the right third, and 13 on the left third, with an average droplet size of 571 µm (± 381 µm). The smallest droplets were 55 µm, the largest 1431 µm. An increase in the number of droplets was found with increased ventilation during the procedure. Blood droplets were more common than secretion droplets. CONCLUSION Contamination of the visor with droplets was demonstrated. Especially in the case of TT in highly infectious patients, e.g., COVID-19 patients, the use of hooded headgear in combination with breathing apparatus with air purification and power supply is recommended to ensure best protection from infection for the surgeon and the surgical assistant.
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Affiliation(s)
- C Plettenberg
- Hals-Nasen-Ohrenklinik, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland.
| | - K Geipel
- Hals-Nasen-Ohrenklinik, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - I Stenin
- Hals-Nasen-Ohrenklinik, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - T Klenzner
- Hals-Nasen-Ohrenklinik, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - M Wagenmann
- Hals-Nasen-Ohrenklinik, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - J Schipper
- Hals-Nasen-Ohrenklinik, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - K Scheckenbach
- Hals-Nasen-Ohrenklinik, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
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Martín-Quintero I, Cervera-Sabater A, Tapias-Perero V, Nieto-Sánchez I, de la Cruz-Pérez J. Air particulate concentration during orthodontic procedures: a pilot study. BMC Oral Health 2021; 21:361. [PMID: 34289851 PMCID: PMC8293529 DOI: 10.1186/s12903-021-01725-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/08/2021] [Indexed: 11/10/2022] Open
Abstract
Background This study evaluates the particle dispersion involved in dental procedures carried out during orthodontic treatments. Variants such as temperature and relative humidity in the dental cabinet were considered. Methods Using a particle counter, a pilot study was conducted, in which 98 consecutive recordings were made during appointments of patients undergoing orthodontic treatments. Temperature, relative humidity and particles present at the beginning (AR) and during the appointment (BR) were recorded. A control record (CR) of temperature, relative humidity and particles present was made before the start of the clinical activity. In addition to conventional statistics, differential descriptive procedures were used to analyse results, and the influence of relative humidity on particle concentration was analysed by statistical modelling with regression equations. Results The number of particles present, regardless of their size, was much higher in AR than in CR (p < .001). The same was true for relative humidity and ambient temperature. The relationship between relative humidity and particle number was determined to be exponential. Limitations of the study The limitations are associated with sample size, environmental conditions of the room and lack of discrimination among the procedures performed. Conclusions This pilot study shows that from the moment a patient enters a dental office, a large number of additional particles are generated. During treatment, the number of particles of 0.3 microns—which have a high capacity to penetrate the respiratory tract-increases. Moreover, a relationship between relative humidity and particle formation is observed. Further studies are needed.
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Affiliation(s)
- Inmaculada Martín-Quintero
- Department of Orthodontics, Universidad Alfonso X El Sabio, Madrid, Spain. .,Centro Odontológico de Innovación y Especialidades Avanzadas, Calle de Albarracín, 35, 28037, Madrid, Spain.
| | | | | | - Iván Nieto-Sánchez
- Department of Orthodontics, Universidad Alfonso X El Sabio, Madrid, Spain
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The Role of HVAC Design and Windows on the Indoor Airflow Pattern and ACH. SUSTAINABILITY 2021. [DOI: 10.3390/su13147931] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The purpose of heating, ventilation, and air conditioning (HVAC) systems are to create optimum thermal comfort and appropriate indoor air quality (IAQ) for occupants. Air ventilation systems can significantly affect the health risk in indoor environments, especially those by contaminated aerosols. Therefore, the main goal of the study is to analyze the indoor airflow patterns in the heating, ventilation, and air conditioning (HVAC) systems and the impact of outlets/windows. The other goal of this study is to simulate the trajectory of the aerosols from a human sneeze, investigate the impact of opening windows on the number of air changes per hour (ACH) and exhibit the role of dead zones with poor ventilation. The final goal is to show the application of computational fluid dynamics (CFD) simulation in improving the HVAC design, such as outlet locations or airflow rate, in addition to the placement of occupants. In this regard, an extensive literature review has been combined with the CFD method to analyze the indoor airflow patterns, ACH, and the role of windows. The airflow pattern analysis shows the critical impact of inflow/outflow and windows. The results show that the CFD model simulation could exhibit optimal placement and safer locations for the occupants to decrease the health risk. The results of the discrete phase simulation determined that the actual ACH could be different from the theoretical ACH as the short circuit and dead zones affect the ACH.
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Mariam, Magar A, Joshi M, Rajagopal PS, Khan A, Rao MM, Sapra BK. CFD Simulation of the Airborne Transmission of COVID-19 Vectors Emitted during Respiratory Mechanisms: Revisiting the Concept of Safe Distance. ACS OMEGA 2021; 6:16876-16889. [PMID: 34250347 PMCID: PMC8247784 DOI: 10.1021/acsomega.1c01489] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/08/2021] [Indexed: 08/31/2023]
Abstract
The airborne transmission of the COVID-19 virus has been suggested as a major mode of transmission in recent studies. In this context, we studied the spatial transmission of COVID-19 vectors in an indoor setting representative of a typical office room. Computational fluid dynamics (CFD) simulations were performed to study the airborne dispersion of particles ejected due to different respiratory mechanisms, i.e., coughing, sneezing, normal talking, and loud talking. Number concentration profiles at a distance of 2 m in front of the emitter at the ventilation rates of 4, 6, and 8 air changes per hour (ACH) were estimated for different combinations of inlet-outlet positions and emitter-receptor configurations. Apart from respiratory events, viz., coughing and sneezing characterized by higher velocity and concentration of ejected particles, normal as well as loud talking was seen to be carrying particles to the receptor for some airflow patterns in the room. This study indicates that the ″rule of thumb based safe distance approach″ cannot be a general mitigation strategy for infection control. Under some scenarios, events with a lower release rate of droplets such as talking (i.e., asymptomatic transmission) can lead to a high concentration of particles persisting for long times. For better removal, the study suggests ″air curtains″ as an appropriate approach, simultaneously highlighting the pitfalls in the ″higher ventilation rate for better removal″ strategy. The inferences for talking-induced particle transmissions are crucial considering that large populations of COVID-19-infected persons are projected to be asymptomatic transmitters.
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Affiliation(s)
- Mariam
- Radiological
Physics and Advisory Division, Bhabha Atomic
Research Centre, Mumbai 400085, India
| | - Ashish Magar
- CFDVR
Institute, Dharamshala, Himachal Pradesh 176219, India
| | - Manish Joshi
- Radiological
Physics and Advisory Division, Bhabha Atomic
Research Centre, Mumbai 400085, India
| | | | - Arshad Khan
- Radiological
Physics and Advisory Division, Bhabha Atomic
Research Centre, Mumbai 400085, India
| | | | - Balvinder K. Sapra
- Radiological
Physics and Advisory Division, Bhabha Atomic
Research Centre, Mumbai 400085, India
- Homi
Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
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Rezaei M, Netz RR. Airborne virus transmission via respiratory droplets: Effects of droplet evaporation and sedimentation. Curr Opin Colloid Interface Sci 2021; 55:101471. [PMID: 34093064 PMCID: PMC8164513 DOI: 10.1016/j.cocis.2021.101471] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Airborne transmission is considered as an important route for the spread of infectious diseases, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and is primarily determined by the droplet sedimentation time, that is, the time droplets spend in air before reaching the ground. Evaporation increases the sedimentation time by reducing the droplet mass. In fact, small droplets can, depending on their solute content, almost completely evaporate during their descent to the ground and remain airborne as so-called droplet nuclei for a long time. Considering that viruses possibly remain infectious in aerosols for hours, droplet nuclei formation can substantially increase the infectious viral air load. Accordingly, the physical-chemical factors that control droplet evaporation and sedimentation times and play important roles in determining the infection risk from airborne respiratory droplets are reviewed in this article.
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Affiliation(s)
- Majid Rezaei
- Fachbereich Physik, Freie Universität Berlin, Berlin, 14195, Germany
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, Berlin, 14195, Germany
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Zhou L, Ayeh SK, Chidambaram V, Karakousis PC. Modes of transmission of SARS-CoV-2 and evidence for preventive behavioral interventions. BMC Infect Dis 2021; 21:496. [PMID: 34049515 PMCID: PMC8160404 DOI: 10.1186/s12879-021-06222-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 05/21/2021] [Indexed: 01/12/2023] Open
Abstract
COVID-19 is a novel disease caused by SARS-CoV-2. During the global vaccination rollout, it is vital to thoroughly understand the modes of transmission of the virus in order to prevent further spread of variants and ultimately to end the pandemic. The current literature suggests that SARS-CoV-2 is transmitted among the human population primarily through respiratory droplets and, to a lesser extent, via aerosols. Transmission appears to be affected by temperature, humidity, precipitation, air currents, pH, and radiation in the ambient environment. Finally, the use of masks or facial coverings, social distancing, and hand washing are effective public health strategies in reducing the risk of exposure and transmission. Additional research is needed to further characterize the relative benefits of specific nonpharmaceutical interventions.
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Affiliation(s)
- Lucas Zhou
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Samuel K Ayeh
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Vignesh Chidambaram
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Petros C Karakousis
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Koch Cancer Research Building, 1550 Orleans St., Room 110, Baltimore, MD, 21287, USA.
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74
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Huang Q, Marzouk T, Cirligeanu R, Malmstrom H, Eliav E, Ren YF. Ventilation Assessment by Carbon Dioxide Levels in Dental Treatment Rooms. J Dent Res 2021; 100:810-816. [PMID: 33973494 PMCID: PMC8120146 DOI: 10.1177/00220345211014441] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
It is important for dental care professionals to reliably assess carbon dioxide (CO2) levels and ventilation rates in their offices in the era of frequent infectious disease pandemics. This study was to evaluate CO2 levels in dental operatories and determine the accuracy of using CO2 levels to assess ventilation rate in dental clinics. Mechanical ventilation rate in air change per hour (ACHVENT) was measured with an air velocity sensor and airflow balancing hood. CO2 levels were measured in these rooms to analyze factors that contributed to CO2 accumulation. Ventilation rates were estimated using natural steady-state CO2 levels during dental treatments and experimental CO2 concentration decays by dry ice or mixing baking soda and vinegar. We compared the differences and assessed the correlations between ACHVENT and ventilation rates estimated by the steady-state CO2 model with low (0.3 L/min, ACHSS30) or high (0.46 L/min, ACHSS46) CO2 generation rates, by CO2 decay constants using dry ice (ACHDI) or baking soda (ACHBV), and by time needed to remove 63% of excess CO2 generated by dry ice (ACHDI63%) or baking soda (ACHBV63%). We found that ACHVENT varied from 3.9 to 35.0 in dental operatories. CO2 accumulation occurred in rooms with low ventilation (ACHVENT ≤6) and overcrowding but not in those with higher ventilation. ACHSS30 and ACHSS46 correlated well with ACHVENT (r = 0.83, P = 0.003), but ACHSS30 was more accurate for rooms with low ACHVENT. Ventilation rates could be reliably estimated using CO2 released from dry ice or baking soda. ACHVENT was highly correlated with ACHDI (r = 0.99), ACHBV (r = 0.98), ACHDI63% (r = 0.98), and ACHBV63% (r = 0.98). There were no statistically significant differences between ACHVENT and ACHDI63% or ACHBV63%. We conclude that ventilation rates could be conveniently and accurately assessed by observing the changes in CO2 levels after a simple mixing of household baking soda and vinegar in dental settings.
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Affiliation(s)
- Q Huang
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | - T Marzouk
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | - R Cirligeanu
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | - H Malmstrom
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | - E Eliav
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
| | - Y-F Ren
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, NY, USA
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75
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Tham KW, Parshetti GK, Anand P, Cheong DKW, Sekhar C. Performance characteristics of a fan filter unit (FFU) in mitigating particulate matter levels in a naturally ventilated classroom during haze conditions. INDOOR AIR 2021; 31:795-806. [PMID: 33215777 DOI: 10.1111/ina.12771] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 11/09/2020] [Indexed: 06/11/2023]
Abstract
The performance of a low-cost fan filter unit (FFU) in mitigating hazardous particulate matter (PM) levels in a naturally ventilated school classroom is presented. The FFU can be considered as a simplified mechanical ventilation and air-conditioning system without heating and cooling functions. The FFU improves indoor air quality through introduction of cleaned outdoor air to flush out internally generated heat and moisture and reducing infiltration by maintaining indoor pressurization. Indoor particle number concentrations were reduced between 85% and 95%. The particle removal performance (PRFFFU ) of the FFU is determined and incorporated into the augmented façade penetration factor (Paug ). A case-specific recursive dynamic mass balance model is used to characterize the infiltration factor (FINF ), deposition rate (K), and the penetration efficiency (Paug ) from continuously monitored indoor and outdoor mass concentration levels. Computed "Paug " (0.07, 0.09, and 0.13) and "FINF " (0.06, 0.08, and 0.11), respectively, for PM10, PM2.5, and PM1 suggest that exposure to PM was significantly reduced indoors. The effectiveness of the FFU for reduced "FINF " and "Paug " may be attributed to its superior filtration, dilution, and exfiltration mechanisms. In comparison with alternative PM mitigation solutions, the FFU is effective, affordable, and sustainable.
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Affiliation(s)
- Kwok Wai Tham
- Department of Building, Centre for Integrated Building Energy and Sustainability in the Tropics (CiBEST), School of Design and Environment, National University of Singapore, Singapore City, Singapore
| | - Ganesh Kashinath Parshetti
- Department of Building, Centre for Integrated Building Energy and Sustainability in the Tropics (CiBEST), School of Design and Environment, National University of Singapore, Singapore City, Singapore
| | - Prashant Anand
- Department of Building, Centre for Integrated Building Energy and Sustainability in the Tropics (CiBEST), School of Design and Environment, National University of Singapore, Singapore City, Singapore
| | - David Kok Wai Cheong
- Department of Building, Centre for Integrated Building Energy and Sustainability in the Tropics (CiBEST), School of Design and Environment, National University of Singapore, Singapore City, Singapore
| | - Chandra Sekhar
- Department of Building, Centre for Integrated Building Energy and Sustainability in the Tropics (CiBEST), School of Design and Environment, National University of Singapore, Singapore City, Singapore
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76
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Javidpour L, BoŽič A, Naji A, Podgornik R. Electrostatic interactions between the SARS-CoV-2 virus and a charged electret fibre. SOFT MATTER 2021; 17:4296-4303. [PMID: 33908595 DOI: 10.1039/d1sm00232e] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
While almost any kind of face mask offers some protection against particles and pathogens of different sizes, the most efficient ones make use of a layered structure where one or more layers are electrically charged. These electret layers are essential for the efficient filtration of difficult-to-capture small particles, yet the exact nature of electrostatic capture with respect to the charge on both the particles and the electret fibres as well as the effect of the immediate environment remain unclear. Here, we explore in detail the electrostatic interactions between the surface of a single charged electret fibre and a model of the SARS-CoV-2 virus. Using Poisson-Boltzmann electrostatics coupled to a detailed spike protein charge regulation model, we show how pH and salt concentration drastically change both the scale and the sign of the interaction. Furthermore, the configuration of the few spike proteins closest to the electret fibre turns out to be as important for the strength of the interaction as their total number on the virus envelope, a direct consequence of spike protein charge regulation. The results of our work elucidate the details of virus electrostatics and contribute to the general understanding of efficient virus filtration mechanisms.
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Affiliation(s)
- Leili Javidpour
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
| | - AnŽe BoŽič
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Ali Naji
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran and School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. and Wenzhou Institute of the University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China
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77
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Dawre S, Maru S. Human respiratory viral infections: Current status and future prospects of nanotechnology-based approaches for prophylaxis and treatment. Life Sci 2021; 278:119561. [PMID: 33915132 PMCID: PMC8074533 DOI: 10.1016/j.lfs.2021.119561] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/09/2021] [Accepted: 04/18/2021] [Indexed: 12/23/2022]
Abstract
Respiratory viral infections are major cause of highly mortal pandemics. They are impacting socioeconomic development and healthcare system globally. These emerging deadly respiratory viruses develop newer survival strategies to live inside host cells and tricking the immune system of host. Currently, medical facilities, therapies and research -development teams of every country kneel down before novel corona virus (SARS-CoV-2) which claimed ~2,828,629 lives till date. Thus, there is urgent requirement of novel treatment strategies to combat against these emerging respiratory viral infections. Nanocarriers come under the umbrella of nanotechnology and offer numerous benefits compared to traditional dosage forms. Further, unique physicochemical properties (size, shape and surface charge) of nanocarriers provide additional advantage for targeted delivery. This review discusses in detail about the respiratory viruses, their transmission mode and cell invasion pathways, survival strategies, available therapies, and nanocarriers for the delivery of therapeutics. Further, the role of nanocarriers in the development of treatment therapy against SARS-CoV-2 is also overviewed.
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Affiliation(s)
- Shilpa Dawre
- Department of Pharmaceutics, School of Pharmacy &, Technology Management, SVKM's NMIMS, Babulde Banks of Tapi River, Mumbai-Agra Road, Shirpur, Maharashtra 425405, India.
| | - Saurabh Maru
- School of Pharmacy and Technology Management, SVKM's NMIMS, Babulde Banks of Tapi River, Mumbai-Agra Road, Shirpur, Maharashtra 425405, India.
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78
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Davies CG, Reilly K, Altermann E, Hendrickson HL. PLAN-M; Mycobacteriophage Endolysins Fused to Biodegradable Nanobeads Mitigate Mycobacterial Growth in Liquid and on Surfaces. Front Microbiol 2021; 12:562748. [PMID: 33981289 DOI: 10.3389/fmicb.2021.562748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
The Mycobacteria are a genus of Actinobacteria that include human pathogens such as Mycobacterium tuberculosis (TB). Active TB disease can spread by airborne transmission to healthcare workers and to their community. The HHMI SEA-PHAGES program has contributed to discovering bacteriophages that are able to infect M. smegmatis MC2 155, a close relative of M. tuberculosis. This collection of diverse Mycobacteriophages is an excellent resource for trialling bacteriophage-sourced enzymes in novel applications. Herein we measured the ability Mycobacteriophage endolysins to lyse their host strain when functionally fused to biodegradable polyhydroxyalkanoate (PHA) nanobeads. PHA nanobeads facilitate both the expression and the application of enzymes to surfaces and have been demonstrated to stabilize a wide array of proteins for practical applications whilst eliminating the challenges of traditional protein purification. We selected two Lysin A and six Lysin B homologs to be functionally fused to the polyhydroxyalkanoate synthase C (PhaC). Expression of these constructs resulted in functional lysins displayed on the surface of PHA nanobeads. The lysins thus directionally displayed on nanobeads lysed up to 79% of the M. smegmatis MC2 155 population using 80 mg/mL of nanobeads in pure culture. In order to determine whether the nanobeads would be effective as a protective layer in PPE we adapted a fabric-based test and observed a maximum of 1 log loss of the cell population after 5 h of exposure on a textile (91% cell lysis). Lysin B enzymes performed better than the Lysin A enzymes as a protective barrier on textiles surface assays. These results suggest that bacterial endolysins are efficient in their action when displayed on PHA nanobeads and can cause significant population mortality in as little as 45 min. Our results provide the proof-of-principle that Mycobacteriophage endolysins can be used on functionalized nanobeads where they can protect surfaces such as personal protective equipment (PPE) that routinely come into contact with aerosolised bacteria.
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Affiliation(s)
- Courtney G Davies
- Massey Phage Whānau, School of Natural and Computational Sciences, Massey University, Auckland, New Zealand
| | | | - Eric Altermann
- AgResearch Ltd., Palmerston North, New Zealand.,Riddet Institute, Massey University, Palmerston North, New Zealand
| | - Heather L Hendrickson
- Massey Phage Whānau, School of Natural and Computational Sciences, Massey University, Auckland, New Zealand.,Infectious Disease Research Centre, Massey University, Palmerston North, New Zealand
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79
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Ball L, Alberti S, Belfortini C, Almondo C, Robba C, Battaglini D, Cravero C, Pelosi P, Caratto V, Ferretti M. Effects of distancing and pattern of breathing on the filtering capability of commercial and custom-made facial masks: An in-vitro study. PLoS One 2021; 16:e0250432. [PMID: 33886642 PMCID: PMC8062003 DOI: 10.1371/journal.pone.0250432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/06/2021] [Indexed: 11/29/2022] Open
Abstract
Background Since the beginning of the COVID-19 pandemics, masking policies have been advocated. While masks are known to prevent transmission towards other individuals, it is unclear if different types of facial masks can protect the user from inhalation. The present study compares in-vitro different commercial and custom-made facial masks at different distances and breathing patterns. Methods Masks were placed on a head mannequin connected to a lung simulator, using a collecting filter placed after the mannequin airway. Certified, commercial and custom-made masks were tested at three different distances between the emitter and the mannequin: 40 cm, 80 cm and 120 cm. Two patterns of breathing were used, simulating normal and polypneic respiration. A solution of methylene blue was nebulized with a jet nebulizer and different mask-distance-breathing pattern combinations were tested. The primary endpoint was the inhaled fraction, defined as the amount of methylene blue detected with spectrophotometry expressed as percent of the amount detected in a reference condition of zero distance and no mask. Findings We observed a significant effect of distance (p < 0.001), pattern of breathing (p = 0.040) and type of mask (p < 0.001) on inhaled fraction. All masks resulted in lower inhaled fraction compared to breathing without mask (p < 0.001 in all comparisons), ranging from 41.1% ± 0.3% obtained with a cotton mask at 40 cm distance with polypneic pattern to <1% for certified FFP3 and the combination of FFP2 + surgical mask at all distances and both breathing pattern conditions. Discussion Distance, type of device and breathing pattern resulted in highly variable inhaled fraction. While the use of all types of masks resulted relevantly less inhalation compared to distancing alone, only high-grade certified devices (FFP3 and the combination of FFP2 + surgical mask) ensured negligible inhaled fraction in all conditions.
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Affiliation(s)
- Lorenzo Ball
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genova, Italy
| | - Stefano Alberti
- Department of Chemistry and Industrial Chemistry, University of Genoa, Genova, Italy
- * E-mail:
| | - Claudio Belfortini
- Department of Chemistry and Industrial Chemistry, University of Genoa, Genova, Italy
| | - Chiara Almondo
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genova, Italy
| | - Chiara Robba
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genova, Italy
| | - Denise Battaglini
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genova, Italy
| | - Carlo Cravero
- Department of Mechanical, Energetic, Management and Transports Engineering, University of Genoa, Genova, Italy
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genova, Italy
| | - Valentina Caratto
- Department of Chemistry and Industrial Chemistry, University of Genoa, Genova, Italy
| | - Maurizio Ferretti
- Department of Chemistry and Industrial Chemistry, University of Genoa, Genova, Italy
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80
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Tackling Airborne Virus Threats in the Food Industry: A Proactive Approach. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18084335. [PMID: 33921880 PMCID: PMC8073175 DOI: 10.3390/ijerph18084335] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/08/2021] [Accepted: 04/08/2021] [Indexed: 01/03/2023]
Abstract
The current SARS-COVID-19 crisis has demonstrated the dangers that airborne virus (AV) pandemics pose to the health of all workers (particularly in the meat processing industry), the economic health of the food industry, and food security. The impact that the current pandemic has had on the food industry points to the need for a proactive rather than reactive approach towards preventing future AV outbreaks. Such a proactive approach should be based on empirical assessments of current AV food safety practices and the development of more robust practices tailored to the culture and needs of the food industry. Moreover, a proactive approach is necessary in order to better prepare the food industry for future AV outbreaks, protect the health of workers, reduce disparities in AV occupational health risks, and enhance the safety of the food supply chain. The aim of this review is to make the case for a new food safety research paradigm that incorporates the intensive study of airborne viruses under conditions that simulate food industry work environments.
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81
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Armaly Z, Kinaneh S, Skorecki K. Renal Manifestations of Covid-19: Physiology and Pathophysiology. J Clin Med 2021; 10:1216. [PMID: 33804075 PMCID: PMC8000200 DOI: 10.3390/jcm10061216] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 02/07/2023] Open
Abstract
Corona virus disease 2019 (COVID-19) imposes a serious public health pandemic affecting the whole world, as it is spreading exponentially. Besides its high infectivity, SARS-CoV-2 causes multiple serious derangements, where the most prominent is severe acute respiratory syndrome as well as multiple organ dysfunction including heart and kidney injury. While the deleterious impact of SARS-CoV-2 on pulmonary and cardiac systems have attracted remarkable attention, the adverse effects of this virus on the renal system is still underestimated. Kidney susceptibility to SARS-CoV-2 infection is determined by the presence of angiotensin-converting enzyme 2 (ACE2) receptor which is used as port of the viral entry into targeted cells, tissue tropism, pathogenicity and subsequent viral replication. The SARS-CoV-2 cellular entry receptor, ACE2, is widely expressed in proximal epithelial cells, vascular endothelial and smooth muscle cells and podocytes, where it supports kidney integrity and function via the enzymatic production of Angiotensin 1-7 (Ang 1-7), which exerts vasodilatory, anti-inflammatory, antifibrotic and diuretic/natriuretic actions via activation of the Mas receptor axis. Loss of this activity constitutes the potential basis for the renal damage that occurs in COVID-19 patients. Indeed, several studies in a small sample of COVID-19 patients revealed relatively high incidence of acute kidney injury (AKI) among them. Although SARS-CoV-1 -induced AKI was attributed to multiorgan failure and cytokine release syndrome, as the virus was not detectable in the renal tissue of infected patients, SARS-CoV-2 antigens were detected in kidney tubules, suggesting that SARS-CoV-2 infects the human kidney directly, and eventually induces AKI characterized with high morbidity and mortality. The mechanisms underlying this phenomenon are largely unknown. However, the fact that ACE2 plays a crucial role against renal injury, the deprivation of the kidney of this advantageous enzyme, along with local viral replication, probably plays a central role. The current review focuses on the critical role of ACE2 in renal physiology, its involvement in the development of kidney injury during SARS-CoV-2 infection, renal manifestations and therapeutic options. The latter includes exogenous administration of Ang (1-7) as an appealing option, given the high incidence of AKI in this ACE2-depleted disorder, and the benefits of ACE2/Ang1-7 including vasodilation, diuresis, natriuresis, attenuation of inflammation, oxidative stress, cell proliferation, apoptosis and coagulation.
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Affiliation(s)
- Zaher Armaly
- Department of Nephrology, Nazareth Hospital, EMMS, Nazareth 16100, Israel;
- The Bar-Ilan University Azrieli Faculty of Medicine, Safed 1311502, Israel;
| | - Safa Kinaneh
- Department of Nephrology, Nazareth Hospital, EMMS, Nazareth 16100, Israel;
| | - Karl Skorecki
- The Bar-Ilan University Azrieli Faculty of Medicine, Safed 1311502, Israel;
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82
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Gallo O, Locatello LG, Mazzoni A, Novelli L, Annunziato F. The central role of the nasal microenvironment in the transmission, modulation, and clinical progression of SARS-CoV-2 infection. Mucosal Immunol 2021; 14:305-316. [PMID: 33244161 PMCID: PMC7690066 DOI: 10.1038/s41385-020-00359-2] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/30/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023]
Abstract
The novel coronavirus SARS-CoV-2 enters into the human body mainly through the ACE2 + TMPRSS2+ nasal epithelial cells. The initial host response to this pathogen occurs in a peculiar immune microenvironment that, starting from the Nasopharynx-Associated Lymphoid Tissue (NALT) system, is the product of a long evolutionary process that is aimed to first recognize exogenous airborne agents. In the present work, we want to critically review the latest molecular and cellular findings on the mucosal response to SARS-CoV-2 in the nasal cavity and in NALT, and to analyze its impact in the subsequent course of COVID-19. Finally, we want to explore the possibility that the regulation of the systemic inflammatory network against the virus can be modulated starting from the initial phases of the nasal and nasopharyngeal response and this may have several clinical and epidemiological implications starting from a mucosal vaccine development.
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Affiliation(s)
- Oreste Gallo
- Department of Otorhinolaryngology, Careggi University Hospital, Largo Brambilla, 3, 50134, Florence, Italy
| | - Luca Giovanni Locatello
- Department of Otorhinolaryngology, Careggi University Hospital, Largo Brambilla, 3, 50134, Florence, Italy
| | - Alessio Mazzoni
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Luca Novelli
- Department of Pathology, Careggi University Hospital, Largo Brambilla, 3, 50134, Florence, Italy
| | - Francesco Annunziato
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy,Flow Cytometry and Immunotherapy Diagnostic Center, Careggi University Hospital, Largo Brambilla, 3, 50134, Florence, Italy
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83
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Božič A, Kanduč M. Relative humidity in droplet and airborne transmission of disease. J Biol Phys 2021; 47:1-29. [PMID: 33564965 PMCID: PMC7872882 DOI: 10.1007/s10867-020-09562-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/22/2020] [Indexed: 02/06/2023] Open
Abstract
A large number of infectious diseases are transmitted by respiratory droplets. How long these droplets persist in the air, how far they can travel, and how long the pathogens they might carry survive are all decisive factors for the spread of droplet-borne diseases. The subject is extremely multifaceted and its aspects range across different disciplines, yet most of them have only seldom been considered in the physics community. In this review, we discuss the physical principles that govern the fate of respiratory droplets and any viruses trapped inside them, with a focus on the role of relative humidity. Importantly, low relative humidity-as encountered, for instance, indoors during winter and inside aircraft-facilitates evaporation and keeps even initially large droplets suspended in air as aerosol for extended periods of time. What is more, relative humidity affects the stability of viruses in aerosol through several physical mechanisms such as efflorescence and inactivation at the air-water interface, whose role in virus inactivation nonetheless remains poorly understood. Elucidating the role of relative humidity in the droplet spread of disease would permit us to design preventive measures that could aid in reducing the chance of transmission, particularly in indoor environment.
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Affiliation(s)
- Anže Božič
- Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Matej Kanduč
- Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana, Slovenia
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84
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Komperda J, Peyvan A, Li D, Kashir B, Yarin AL, Megaridis CM, Mirbod P, Paprotny I, Cooper LF, Rowan S, Stanford C, Mashayek F. Computer simulation of the SARS-CoV-2 contamination risk in a large dental clinic. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:033328. [PMID: 33897241 PMCID: PMC8060974 DOI: 10.1063/5.0043934] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/16/2021] [Indexed: 05/18/2023]
Abstract
COVID-19, caused by the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) virus, has been rapidly spreading worldwide since December 2019, causing a public health crisis. Recent studies showed SARS-CoV-2's ability to infect humans via airborne routes. These motivated the study of aerosol and airborne droplet transmission in a variety of settings. This study performs a large-scale numerical simulation of a real-world dentistry clinic that contains aerosol-generating procedures. The simulation tracks the dispersion of evaporating droplets emitted during ultrasonic dental scaling procedures. The simulation considers 25 patient treatment cubicles in an open plan dentistry clinic. The droplets are modeled as having a volatile (evaporating) and nonvolatile fraction composed of virions, saliva, and impurities from the irrigant water supply. The simulated clinic's boundary and flow conditions are validated against experimental measurements of the real clinic. The results evaluate the behavior of large droplets and aerosols. We investigate droplet residence time and travel distance for different droplet diameters, surface contamination due to droplet settling and deposition, airborne aerosol mass concentration, and the quantity of droplets that escape through ventilation. The simulation results raise concerns due to the aerosols' long residence times (averaging up to 7.31 min) and travel distances (averaging up to 24.45 m) that exceed social distancing guidelines. Finally, the results show that contamination extends beyond the immediate patient treatment areas, requiring additional surface disinfection in the clinic. The results presented in this research may be used to establish safer dental clinic operating procedures, especially if paired with future supplementary material concerning the aerosol viral load generated by ultrasonic scaling and the viral load thresholds required to infect humans.
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Affiliation(s)
- Jonathan Komperda
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Ahmad Peyvan
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Dongru Li
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Babak Kashir
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Alexander L. Yarin
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Constantine M. Megaridis
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Parisa Mirbod
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Igor Paprotny
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Lyndon F. Cooper
- College of Dentistry, University of Illinois at Chicago, Chicago, Illinois 60612, USA
| | - Susan Rowan
- College of Dentistry, University of Illinois at Chicago, Chicago, Illinois 60612, USA
| | - Clark Stanford
- College of Dentistry, University of Illinois at Chicago, Chicago, Illinois 60612, USA
| | - Farzad Mashayek
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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85
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Kampf G, Jatzwauk L. [Is Disinfection of Public Surfaces useful for the Prevention of SARS-CoV-2 Infections?]. DAS GESUNDHEITSWESEN 2021; 83:180-185. [PMID: 33540430 PMCID: PMC8043670 DOI: 10.1055/a-1335-4549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Measures to control SARS-CoV-2 often include the regular disinfection of public surfaces. The frequency of SARS-CoV-2 detection on surfaces in the surrounding of confirmed cases was evaluated in this systematic review. Overall, 26 studies showed 0 and 100% rates of contamination with SARS-CoV-2 RNA on surfaces in the surrounding of patients. Seven studies with at least 100 samples mostly showed detection rates between 1.4 and 19%. Two other studies did not detect infectious SARS-CoV-2 on any surface. Similar results were obtained from surfaces in the surrounding of confirmed SARS- and influenza-patients. A contamination of public surfaces with infectious virus is considerably less likely because there are much less potential viral spreaders around a surface, the contact time between a person and the surface is much shorter, and the asymptomatic carriers typically have no symptoms. In addition, a hand contact with a contaminated surface transfers only a small part of the viral load. A simple cleaning reduces the number of infectious viruses already by 2 log10-steps. That is why public surfaces should in general be cleaned because the wide use of biocidal agents for surface disinfection further increases the microbial selection pressure without an expectable health benefit.
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Affiliation(s)
- Günter Kampf
- Institut für Hygiene und Umweltmedizin, Universitätsmedizin Greifswald, Greifswald, Deutschland
| | - Lutz Jatzwauk
- Krankenhaushygiene, Universitätsklinikum Carl Gustav Carus, Dresden, Deutschland
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86
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Scantling-Birch Y, Newton R, Naveed H, Rajak S, Bhutta MF. Healthcare worker protection against epidemic viral respiratory disease. Postgrad Med J 2021; 98:131-137. [PMID: 33637641 DOI: 10.1136/postgradmedj-2020-139555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 01/20/2021] [Indexed: 01/08/2023]
Abstract
Lower respiratory infections are often caused or precipitated by viruses and are a leading cause of global morbidity and mortality. Mutations in these viral genomes can produce highly infectious strains that transmit across species and have the potential to initiate epidemic, or pandemic, human viral respiratory disease. Transmission between humans primarily occurs via the airborne route and is accelerated by our increasingly interconnected and globalised society. To this date, there have been four major human viral respiratory outbreaks in the 21st century. Healthcare workers (HCWs) are at particular risk during respiratory epidemics or pandemics. This is due to crowded working environments where social distancing, or wearing respiratory personal protective equipment for prolonged periods, might prove difficult, or performing medical procedures that increase exposure to virus-laden aerosols, or bodily fluids. This review aims to summarise the evidence and approaches to occupational risk and protection of HCWs during epidemic or pandemic respiratory viral disease.
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Affiliation(s)
| | - Richard Newton
- Department of Anaesthesia, Royal Sussex County Hospital, Brighton, UK
| | - Hasan Naveed
- Department of Ophthalmology, Royal Surrey County Hospital NHS Foundation Trust, Guildford, Surrey, UK.,Brighton and Sussex Medical School, University of Sussex, Falmer Campus, Brighton, UK
| | - Saul Rajak
- Brighton and Sussex Medical School, University of Sussex, Falmer Campus, Brighton, UK.,Department of Oculoplastics, Sussex Eye Hospital, Brighton, UK
| | - Mahmood F Bhutta
- Brighton and Sussex Medical School, University of Sussex, Falmer Campus, Brighton, UK.,Department of Ear, Nose & Throat, Royal Sussex County Hospital, Brighton, UK
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87
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Wong SSW, Venugopalan LP, Beaussart A, Karnam A, Mohammed MRS, Jayapal JM, Bretagne S, Bayry J, Prajna L, Kuppamuthu D, Latgé JP, Aimanianda V. Species-Specific Immunological Reactivities Depend on the Cell-Wall Organization of the Two Aspergillus, Aspergillus fumigatus and A. flavus. Front Cell Infect Microbiol 2021; 11:643312. [PMID: 33718288 PMCID: PMC7950546 DOI: 10.3389/fcimb.2021.643312] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/15/2021] [Indexed: 12/12/2022] Open
Abstract
Although belong to the same genus, Aspergillus fumigatus is primarily involved in invasive pulmonary infection, whereas Aspergillus flavus is a common cause of superficial infection. In this study, we compared conidia (the infective propagules) of these two Aspergillus species. In immunocompetent mice, intranasal inoculation with conidia of A. flavus resulted in significantly higher inflammatory responses in the lungs compared to mice inoculated with A. fumigatus conidia. In vitro assays revealed that the dormant conidia of A. flavus, unlike A. fumigatus dormant conidia, are immunostimulatory. The conidial surface of A. fumigatus was covered by a rodlet-layer, while that of A. flavus were presented with exposed polysaccharides. A. flavus harbored significantly higher number of proteins in its conidial cell wall compared to A. fumigatus conidia. Notably, β-1,3-glucan in the A. flavus conidial cell-wall showed significantly higher percentage of branching compared to that of A. fumigatus. The polysaccharides ensemble of A. flavus conidial cell wall stimulated the secretion of proinflammatory cytokines, and conidial cell wall associated proteins specifically stimulated IL-8 secretion from the host immune cells. Furthermore, the two species exhibited different sensitivities to antifungal drugs targeting cell wall polysaccharides, proposing the efficacy of species-specific treatment strategies. Overall, the species-specific organization of the conidial cell wall could be important in establishing infection by the two Aspergillus species.
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Affiliation(s)
- Sarah Sze Wah Wong
- Institut Pasteur, Unité des Aspergillus, Paris, France.,Institut Pasteur, Molecular Mycology Unit, CNRS, UMR-2000, Paris, France
| | | | | | - Anupama Karnam
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherché des Cordeliers, Sorbonne Université, Université de Paris, Paris, France
| | | | - Jeya Maheshwari Jayapal
- Department of Proteomics & Ocular Microbiology, Aravind Medical Research Foundation, Madurai, India
| | - Stéphane Bretagne
- Institut Pasteur, Molecular Mycology Unit, CNRS, UMR-2000, Paris, France
| | - Jagadeesh Bayry
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherché des Cordeliers, Sorbonne Université, Université de Paris, Paris, France
| | - Lalitha Prajna
- Department of Ocular Microbiology, Aravind Eye Hospital, Madurai, India
| | - Dharmalingam Kuppamuthu
- Department of Proteomics & Ocular Microbiology, Aravind Medical Research Foundation, Madurai, India
| | | | - Vishukumar Aimanianda
- Institut Pasteur, Unité des Aspergillus, Paris, France.,Institut Pasteur, Molecular Mycology Unit, CNRS, UMR-2000, Paris, France
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88
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Li H, Leong FY, Xu G, Kang CW, Lim KH, Tan BH, Loo CM. Airborne dispersion of droplets during coughing: a physical model of viral transmission. Sci Rep 2021; 11:4617. [PMID: 33633316 PMCID: PMC7907382 DOI: 10.1038/s41598-021-84245-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 02/08/2021] [Indexed: 01/31/2023] Open
Abstract
The Covid-19 pandemic has focused attention on airborne transmission of viruses. Using realistic air flow simulation, we model droplet dispersion from coughing and study the transmission risk related to SARS-CoV-2. Although this model defines most airborne droplets as 8-16 µm in diameter, we infer that larger droplets of 32-40 µm in diameter may potentially be more infectious due to higher viral content. Use of face masks is therefore recommended for both personal and social protection. We found social distancing effective at reducing transmission potential across all droplet sizes. However, the presence of a human body 1 m away modifies the aerodynamics so that downstream droplet dispersion is enhanced, which has implications on safe distancing in queues. At 1 m distance, we found that an average of 0.55 viral copies is inhaled for a cough at median loading, scalable up to 340 copies at peak loading. Droplet evaporation results in significant reduction in droplet counts, but airborne transmission remains possible even under low humidity conditions.
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Affiliation(s)
- Hongying Li
- A*STAR Institute of High Performance Computing, 1 Fusionopolis Way, Connexis, 138632, Singapore
| | - Fong Yew Leong
- A*STAR Institute of High Performance Computing, 1 Fusionopolis Way, Connexis, 138632, Singapore.
| | - George Xu
- A*STAR Institute of High Performance Computing, 1 Fusionopolis Way, Connexis, 138632, Singapore
| | - Chang Wei Kang
- A*STAR Institute of High Performance Computing, 1 Fusionopolis Way, Connexis, 138632, Singapore
| | - Keng Hui Lim
- A*STAR Institute of High Performance Computing, 1 Fusionopolis Way, Connexis, 138632, Singapore
| | - Ban Hock Tan
- Department of Infectious Diseases, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore
| | - Chian Min Loo
- Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore
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89
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Mohan SV, Hemalatha M, Kopperi H, Ranjith I, Kumar AK. SARS-CoV-2 in environmental perspective: Occurrence, persistence, surveillance, inactivation and challenges. CHEMICAL ENGINEERING JOURNAL (LAUSANNE, SWITZERLAND : 1996) 2021; 405:126893. [PMID: 32901196 PMCID: PMC7471803 DOI: 10.1016/j.cej.2020.126893] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 05/03/2023]
Abstract
The unprecedented global spread of the severe acute respiratory syndrome (SARS) caused by SARS-CoV-2 is depicting the distressing pandemic consequence on human health, economy as well as ecosystem services. So far novel coronavirus (CoV) outbreaks were associated with SARS-CoV-2 (2019), middle east respiratory syndrome coronavirus (MERS-CoV, 2012), and SARS-CoV-1 (2003) events. CoV relates to the enveloped family of Betacoronavirus (βCoV) with positive-sense single-stranded RNA (+ssRNA). Knowing well the persistence, transmission, and spread of SARS-CoV-2 through proximity, the faecal-oral route is now emerging as a major environmental concern to community transmission. The replication and persistence of CoV in the gastrointestinal (GI) tract and shedding through stools is indicating a potential transmission route to the environment settings. Despite of the evidence, based on fewer reports on SARS-CoV-2 occurrence and persistence in wastewater/sewage/water, the transmission of the infective virus to the community is yet to be established. In this realm, this communication attempted to review the possible influx route of the enteric enveloped viral transmission in the environmental settings with reference to its occurrence, persistence, detection, and inactivation based on the published literature so far. The possibilities of airborne transmission through enteric virus-laden aerosols, environmental factors that may influence the viral transmission, and disinfection methods (conventional and emerging) as well as the inactivation mechanism with reference to the enveloped virus were reviewed. The need for wastewater epidemiology (WBE) studies for surveillance as well as for early warning signal was elaborated. This communication will provide a basis to understand the SARS-CoV-2 as well as other viruses in the context of the environmental engineering perspective to design effective strategies to counter the enteric virus transmission and also serves as a working paper for researchers, policy makers and regulators.
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Key Words
- (h+), Photoholes
- +ssRNA, Positive Sense Single-Stranded RNA
- A-WWTS, Algal-WWTS
- ACE2, Angiotensin-converting enzyme 2
- AH, Absolute Humidity
- AOPs, Advanced Oxidation Processes
- ASP, Activate Sludge Process
- Aerosols
- BCoV, Bovine Enteric Coronavirus)
- BSL, Biosafety Level
- BVDV1, Bovine Viral Diarrhea Virus Type 1
- BVDV2, Bovine Viral Diarrhea Virus Type 2
- BoRv, Bovine Rotavirus Group A
- CCA, Carbon Covered Alumina
- CNT, Carbon Nanotubes
- COVID-19
- COVID-19, Coronavirus Disease 2019
- CRFK, Crandell Reese feline kidney cell line (CRFK)
- CVE, Coxsackievirus B5
- ClO2, Chlorine dioxide
- Cl−, Chlorine
- Cys, Cysteine
- DBP, Disinfection by-products
- DBT, L2 and Delayed Brain Tumor Cell Cultures
- DMEM, Dulbecco’s Modified Eagle Medium
- DNA, deoxyribose nucleic acid
- Disinfection
- E gene, Envelope protein gene
- EV, Echovirus 11
- Enteric virus
- Enveloped virus
- FC, Free Chlorine
- FFP3, Filtering Face Piece
- FIPV, Feline infectious peritonitis virus
- GI, Gastrointestinal tract
- H2O2, Hydrogen Peroxide
- H3N2, InfluenzaA
- H6N2, Avian influenza virus
- HAV, Hepatitis A virus (HAV)
- HAdV, Human Adenovirus
- HCoV, Human CoV
- HEV, Hepatitis E virus
- HKU1, Human CoV1
- ICC-PCR, Integrated Cell Culture with PCR
- JCV, JCV polyomavirus
- MALDI-TOF MS, Mass Spectrometry
- MBR, Membrane Bioreactor (MBR)
- MERS-CoV, Middle East Respiratory Syndrome Coronavirus
- MHV, Murine hepatitis virus
- MNV-1, Murine Norovirus
- MWCNTs, Multiwalled Carbon Nanotubes
- Met, Methionine
- N gene, Nucleocapsid protein gene
- NCoV, Novel coronavirus
- NGS, Next generation sequencing
- NTP, Non-Thermal Plasma
- O2, Singlet Oxygen
- O3, Ozone
- ORF, Open Reading Frame
- PAA, Para Acetic Acid
- PCR, Polymerase Chain Reaction
- PEC, Photoelectrocatalytical
- PEG, Polyethylene Glycol
- PFU, Plaque Forming Unit
- PMMoV, Pepper Mild Mottle Virus
- PMR, Photocatalytic Membrane Reactors
- PPE, Personal Protective Equipment
- PTAF, Photocatalytic Titanium Apatite Filter
- PV-1, Polivirus-1
- PV-3, Poliovirus 3
- PVDF, Polyvinylidene Fluoride
- Qβ, bacteriophages
- RH, Relative Humidity
- RNA, Ribose nucleic acid
- RONS, Reactive Oxygen and/or Nitrogen Species
- RT-PCR, Real Time Polymerase Chain Reaction
- RVA, Rotaviruses A
- SARS-CoV-1, Severe Acute Respiratory Syndrome Coronavirus 1
- SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2
- SBR, Sequential Batch Reactor
- SODIS, Solar water disinfection
- STP, Sewage Treatment Plant
- Sewage
- T90, First order reaction time required for completion of 90%
- T99.9, First order reaction time required for completion of 99.9%
- TGEV, Porcine Coronavirus Transmissible Gastroenteritis Virus
- TGEV, Transmissible Gastroenteritis
- Trp, Tryptophan
- Tyr, Tyrosine
- US-EPA, United States Environmental Protection Agency
- UV, Ultraviolet
- WBE, Wastewater-Based Epidemiology
- WWT, Wastewater Treatment
- WWTPs, Wastewater Treatment Plants
- dPCR, Digital PCR
- ds, Double Stranded
- dsDNA, Double Stranded DNA
- log10, logarithm with base 10
- qRT-PCR, quantitative RT-PCR
- ss, Single Stranded
- ssDNA, Single Stranded DNA
- ssRNA, Single Stranded RNA
- αCoV, Alphacoronavirus
- βCoV, Betacoronavirus
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Affiliation(s)
- S Venkata Mohan
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering (DEEE), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Indian Institute of Chemical Technology (CSIR-IICT) Campus, Hyderabad 500007, India
| | - Manupati Hemalatha
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering (DEEE), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Indian Institute of Chemical Technology (CSIR-IICT) Campus, Hyderabad 500007, India
| | - Harishankar Kopperi
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering (DEEE), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
| | - I Ranjith
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering (DEEE), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
| | - A Kiran Kumar
- Bioengineering and Environmental Sciences Lab, Department of Energy and Environmental Engineering (DEEE), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
- CSIR-Indian Institute of Chemical Technology (CSIR-IICT) Dispensary, Hyderabad 500007, India
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90
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Lou M, Liu S, Gu C, Hu H, Tang Z, Zhang Y, Xu C, Li F. The bioaerosols emitted from toilet and wastewater treatment plant: a literature review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:2509-2521. [PMID: 33098562 PMCID: PMC7585356 DOI: 10.1007/s11356-020-11297-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/18/2020] [Indexed: 05/05/2023]
Abstract
The aerosols harboring microorganisms and viruses released from the wastewater system into the air have greatly threatened the health and safety of human beings. The wastewater systems, including toilet and wastewater treatment plant (WWTP), are the major locations of epidemic infections due to the extensive sources of aerosols, as well as multifarious germs and microorganisms. Viruses and microorganisms may transport from both toilet and hospital into municipal pipes and subsequently into WWTP, which accounts for the main source of bioaerosols dispersed in the air of the wastewater system. This review aims to elaborate the generation, transmission, and diffusion processes of bioaerosols at toilet and WWTP. Moreover, the main factors affecting bioaerosol transmission and the corresponding prevention strategies for the airborne and inhaled bioaerosols are also discussed. Collectively, this review highlights the importance of managing bioaerosol occurrence in the wastewater system, which has aroused increasing concern from the public.
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Affiliation(s)
- Mengmeng Lou
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Shuai Liu
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Chunjie Gu
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Huimin Hu
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Zhengkun Tang
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Yaopeng Zhang
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Chenye Xu
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China.
- State Environmental Science and Engineering Centre for Pollution Treatment and Control in Textile Industry, Shanghai, 201620, China.
| | - Fang Li
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China.
- State Environmental Science and Engineering Centre for Pollution Treatment and Control in Textile Industry, Shanghai, 201620, China.
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91
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Di Girolamo P. Assessment of the potential role of atmospheric particulate pollution and airborne transmission in intensifying the first wave pandemic impact of SARS-CoV-2/COVID-19 in Northern Italy. BULLETIN OF ATMOSPHERIC SCIENCE AND TECHNOLOGY 2020; 1:515-550. [PMID: 38624634 PMCID: PMC7750914 DOI: 10.1007/s42865-020-00024-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/24/2020] [Indexed: 02/01/2023]
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which exploded in Wuhan (Hebei Region, China) in late 2019, has later spread around the world, causing pandemic effects on humans. During the first wave of the pandemic, Italy, and especially its Northern regions around the Po Valley, faced severe consequences in terms of infected individuals and casualties (more than 31,000 deaths and 255,000 infected people by mid-May 2020). While the spread and effective impact of the virus is primarily related to the lifestyles and social habits of the different human communities, environmental and meteorological factors also play a role. Among these, particulate pollution may directly impact the human respiratory system or act as virus carrier, thus behaving as potential amplifying factor in the pandemic spread of SARS-CoV-2. Enhanced levels of PM2.5 and PM10 particles in Northern Italy were observed over the 2-month period preceding the virus pandemic spread. Threshold levels for PM10 (< 50 μg/m3) were exceeded on 20-35 days over the period January-February 2020 in many areas in the Po Valley, where major effects in terms of infections and casualties occurred, with levels in excess of 80 μg/m3 occasionally observed in the 1-3 weeks preceding the contagious activation around February 25, 2020. Threshold values for PM2.5 indicated in WHO air quality guidelines (< 25 μg/m3) were exceeded on more than 40 days over the period January-February 2020 in large portions of the Po Valley, with levels up to 70 μg/m3 observed in the weeks preceding the contagious activation. In this paper, PM10 particle measurements are compared with epidemiologic parameters' data. Specifically, a statistical analysis is carried out to correlate the infection rate, or incidence of the pathology, the mortality rate, and the case fatality rate with PM concentrations. The study considers epidemiologic data for all 110 Italian provinces, as reported by the Italian Statistics Institute, over the period 20 February-31 March 2020. Corresponding PM10 concentrations covering the period 15-26 February 2020 were collected from the network of air quality monitoring stations run by different regional and provincial environment agencies. The case fatality rate is found to be highly correlated to the average PM10 concentration, with a correlation coefficient of 0.89 and a slope of the regression line of (6.7 ± 0.3) × 10-3 m3/μg, which implies a doubling (from 3 to 6%) of the mortality rate of infected patients for an average PM10 concentration increase from 22 to 27 μg/m3. Infection and mortality rates are also found to be correlated with PM10 concentrations, with correlation coefficients being 0.82 and 0.80, respectively, and the slopes of the regression lines indicating a doubling (from 1 to 2‰) of the infection rate and a tripling (from 0.1 to 0.3‰) of the mortality rate for an average PM10 concentration increase from 25 to 29 μg/m3. Considerations on the exhaled particles' sizes, their concentrations and residence times, the transported viral dose and the minimum infective dose, in combination with PM2.5 and PM10 pollution measurements and an analytical microphysical model, allowed assessing the potential role of airborne transmission through virus-laden PM particles, in addition to droplet and the traditional airborne transmission, in conveying SARS-CoV-2 in the human respiratory system. In specific circumstances which can be found in indoor environments, the number of small potentially infectious particles coalescing on PM2.5 and PM10 particles is estimated to exceed the number of infectious particles needed to activate COVID-19 infection in humans.
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Affiliation(s)
- Paolo Di Girolamo
- Scuola di Ingegneria, Università degli Studi della Basilicata, Viale dell’Ateneo Lucano, 10, 85100 Potenza, Italy
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92
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Zhang XS, Duchaine C. SARS-CoV-2 and Health Care Worker Protection in Low-Risk Settings: a Review of Modes of Transmission and a Novel Airborne Model Involving Inhalable Particles. Clin Microbiol Rev 2020; 34:e00184-20. [PMID: 33115724 PMCID: PMC7605309 DOI: 10.1128/cmr.00184-20] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Since the beginning of the COVID-19 pandemic, there has been intense debate over SARS-CoV-2's mode of transmission and appropriate personal protective equipment for health care workers in low-risk settings. The objective of this review is to identify and appraise the available evidence (clinical trials and laboratory studies on masks and respirators, epidemiological studies, and air sampling studies), clarify key concepts and necessary conditions for airborne transmission, and shed light on knowledge gaps in the field. We find that, except for aerosol-generating procedures, the overall data in support of airborne transmission-taken in its traditional definition (long-distance and respirable aerosols)-are weak, based predominantly on indirect and experimental rather than clinical or epidemiological evidence. Consequently, we propose a revised and broader definition of "airborne," going beyond the current droplet and aerosol dichotomy and involving short-range inhalable particles, supported by data targeting the nose as the main viral receptor site. This new model better explains clinical observations, especially in the context of close and prolonged contacts between health care workers and patients, and reconciles seemingly contradictory data in the SARS-CoV-2 literature. The model also carries important implications for personal protective equipment and environmental controls, such as ventilation, in health care settings. However, further studies, especially clinical trials, are needed to complete the picture.
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Affiliation(s)
- X Sophie Zhang
- Department of General Medicine, CIUSSS Centre-Sud-de-l'Île-de-Montréal, Montreal, Canada
- CHSLD Bruchési and CHSLD Jean De La Lande, Montreal, Canada
- GMF-U Faubourgs, Montreal, Canada
- Centre de Recherche et d'Aide aux Narcomanes, Montreal, Canada
| | - Caroline Duchaine
- Department of Biochemistry, Microbiology, and Bioinformatics, Université Laval, Quebec City, Canada
- Quebec Heart and Lung Institute-Université Laval (CRIUCPQ), Quebec City, Canada
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93
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Rasul RM, Tamilarasi Muniandy M, Zakaria Z, Shah K, Chee CF, Dabbagh A, Rahman NA, Wong TW. A review on chitosan and its development as pulmonary particulate anti-infective and anti-cancer drug carriers. Carbohydr Polym 2020; 250:116800. [PMID: 33049807 PMCID: PMC7434482 DOI: 10.1016/j.carbpol.2020.116800] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/17/2020] [Accepted: 07/19/2020] [Indexed: 12/24/2022]
Abstract
Chitosan, as a biodegradable and biocompatible polymer, is characterized by anti-microbial and anti-cancer properties. It lately has received a widespread interest for use as the pulmonary particulate backbone materials of drug carrier for the treatment of infectious disease and cancer. The success of chitosan as pulmonary particulate drug carrier is a critical interplay of their mucoadhesive, permeation enhancement and site/cell-specific attributes. In the case of nanocarriers, various microencapsulation and micro-nano blending systems have been devised to equip them with an appropriate aerodynamic character to enable efficient pulmonary aerosolization and inhalation. The late COVID-19 infection is met with acute respiratory distress syndrome and cancer. Chitosan and its derivatives are found useful in combating HCoV and cancer as a function of their molecular weight, substituent type and its degree of substitution. The interest in chitosan is expected to rise in the next decade from the perspectives of drug delivery in combination with its therapeutic performance.
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Affiliation(s)
- Ruhisy Mohd Rasul
- Non-Destructive Biomedical and Pharmaceutical Research Centre, iPROMISE, Universiti Teknologi MARA Selangor, 42300, Puncak Alam, Selangor, Malaysia; Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor, Malaysia
| | - M Tamilarasi Muniandy
- Non-Destructive Biomedical and Pharmaceutical Research Centre, iPROMISE, Universiti Teknologi MARA Selangor, 42300, Puncak Alam, Selangor, Malaysia; Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Zabliza Zakaria
- Non-Destructive Biomedical and Pharmaceutical Research Centre, iPROMISE, Universiti Teknologi MARA Selangor, 42300, Puncak Alam, Selangor, Malaysia; Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia
| | - Kifayatullah Shah
- Department of Pharmaceutics, Faculty of Pharmacy, Gomal University, Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan
| | - Chin Fei Chee
- Nanotechnology & Catalysis Research Centre, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ali Dabbagh
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University, Subang Jaya, Malaysia
| | - Noorsaadah Abd Rahman
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Tin Wui Wong
- Non-Destructive Biomedical and Pharmaceutical Research Centre, iPROMISE, Universiti Teknologi MARA Selangor, 42300, Puncak Alam, Selangor, Malaysia; Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia; Sino-Malaysia Molecular Oncology and Traditional Chinese Medicine Delivery Joint Research Centre, Medical College, Yangzhou University. China.
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94
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Guzman MI. An overview of the effect of bioaerosol size in coronavirus disease 2019 transmission. Int J Health Plann Manage 2020; 36:257-266. [PMID: 33295073 PMCID: PMC8049017 DOI: 10.1002/hpm.3095] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 11/13/2020] [Accepted: 11/25/2020] [Indexed: 01/01/2023] Open
Abstract
The fast spread of coronavirus disease 2019 (COVID‐19) constitutes a worldwide challenge to the public health, educational and trade systems, affecting the overall well‐being of human societies. The high transmission and mortality rates of this virus, and the unavailability of a vaccine or treatment, resulted in the decision of multiple governments to enact measures of social distancing. Such measures can reduce the exposure to bioaerosols, which can result in pathogen deposition in the respiratory tract of the host causing disease and an immunological response. Thus, it is important to consider the validity of the proposal for keeping a distance of at least 2 m from other persons to avoid the spread of COVID‐19. This work reviews the effect of aerodynamic diameter (size) of particles carrying RNA copies of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). A SARS‐CoV‐2 carrier person talking, sneezing or coughing at distance of 2 m can still provide a pathogenic bioaerosol load with submicron particles that remain viable in air for up to 3 h for exposure of healthy persons near and far from the source in a stagnant environment. The deposited bioaerosol creates contaminated surfaces, which if touched can act as a path to introduce the pathogen by mouth, nose or eyes and cause disease.
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Affiliation(s)
- Marcelo I Guzman
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
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95
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COVID-19: Understanding the Pandemic Emergence, Impact and Infection Prevalence Worldwide. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2020. [DOI: 10.22207/jpam.14.4.02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Coronavirus disease (COVID-19) has showed high transmission across the continents due to Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) with total infected cases of around ~ 44 million people. This communicable virus that initiated from the Wuhan city of China in the month of December 2020 has now spread to 189 different countries with 1.1 million fatalities worldwide (till 28 Oct, 2020). The World Health Organization (WHO) declared this outbreak as Public Health Emergency of International Concern in January, 2020. The infection spreads mainly due to contact with infected droplets or fomites, highlighting flu like symptoms initially, which may further progress into severe pneumonia and respiratory failure, often observed in elderly patients with prehistory of other diseases. The diagnosis is based on detection of viral antigen, human antibody and viral gene (RT-PCR). Further, various other diagnostic tools including X-ray, CT-scan are used for imaging purpose, recently artificial intelligence based imaging (contactless scanning) gained popularity. Generally testing of existing drugs (repurposing) and development of new molecules are the main strategies adopted by researchers. However, as per initial findings, various drugs, monoclonal antibody and plasma therapy were found to show effectiveness against COVID-19. Further, many vaccine candidates have entered or will soon enter phase III clinical testing. This disease has further challenged the global economy. Thus, this review uniquely compares the strategies adopted by developed and developing countries worldwide including protective measures like lockdown, continuous testing, utilizing latest tools (artificial intelligence) in curbing this infection spread.
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96
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Mony C, Vandenkoornhuyse P, Bohannan BJM, Peay K, Leibold MA. A Landscape of Opportunities for Microbial Ecology Research. Front Microbiol 2020; 11:561427. [PMID: 33329422 PMCID: PMC7718007 DOI: 10.3389/fmicb.2020.561427] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/30/2020] [Indexed: 11/13/2022] Open
Abstract
Microbes encompass tremendous biodiversity, provide support to all living forms, including humans, and play an important role in many ecosystem services. The rules that govern microorganism community assembly are increasingly revealed due to key advances in molecular and analytical methods but their understanding remain a key challenge in microbial ecology. The existence of biogeographic patterns within microbial communities has been established and explained in relation to landscape-scale processes, including selection, drift, dispersal and mutation. The effect of habitat patchiness on microorganisms' assembly rules remains though incompletely understood. Here, we review how landscape ecology principles can be adapted to explore new perspectives on the mechanisms that determine microbial community structure. To provide a general overview, we characterize microbial landscapes, the spatial and temporal scales of the mechanisms that drive microbial assembly and the feedback between microorganisms and landscape structure. We provide evidence for the effects of landscape heterogeneity, landscape fragmentation and landscape dynamics on microbial community structure, and show that predictions made for macro-organisms at least partly also apply to microorganisms. We explain why emerging metacommunity approaches in microbial ecology should include explicit characterization of landscape structure in their development and interpretation. We also explain how biotic interactions, such as competition, prey-predator or mutualist relations may influence the microbial landscape and may be involved in the above-mentioned feedback process. However, we argue that the application of landscape ecology to the microbial world cannot simply involve transposing existing theoretical frameworks. This is due to the particularity of these organisms, in terms of size, generation time, and for some of them, tight interaction with hosts. These characteristics imply dealing with unusual and dependent space and time scales of effect. Evolutionary processes have also a strong importance in microorganisms' response to their landscapes. Lastly, microorganisms' activity and distribution induce feedback effects on the landscape that have to be taken into account. The transposition of the landscape ecology framework to microorganisms provides many challenging research directions for microbial ecology.
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Affiliation(s)
- Cendrine Mony
- UMR CNRS ECOBIO, Université de Rennes, Rennes, France
| | | | | | - Kabir Peay
- Department of Biology, University of Stanford, Stanford, CA, United States
| | - Mathew A Leibold
- Department of Biology, University of Florida, Gainesville, FL, United States
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97
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Bueckert M, Gupta R, Gupta A, Garg M, Mazumder A. Infectivity of SARS-CoV-2 and Other Coronaviruses on Dry Surfaces: Potential for Indirect Transmission. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E5211. [PMID: 33218120 PMCID: PMC7698891 DOI: 10.3390/ma13225211] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/09/2020] [Accepted: 11/16/2020] [Indexed: 01/03/2023]
Abstract
The unwavering spread of COVID-19 has taken the world by storm. Preventive measures like social distancing and mask usage have been taken all around the globe but still, as of September 2020, the number of cases continues to rise in many countries. Evidently, these measures are insufficient. Although decreases in population density and surges in the public's usage of personal protective equipment can mitigate direct transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), indirect transmission of the virus is still probable. By summarizing the current state of knowledge on the stability of coronaviruses on dry materials, this review uncovers the high potential for SARS-CoV-2 transmission through contaminated surfaces (i.e., fomites) and prompts future research. Fully contextualized data on coronavirus persistence are presented. The methods and limitations to testing the stability of coronaviruses are explored, and the SARS-CoV-2 representativeness of different coronaviruses is analyzed. The factors which dictate the persistence of coronaviruses on surfaces (media, environmental conditions, and material-type) are investigated, and the review is concluded by encouraging material innovation to combat the current pandemic. To summarize, SARS-CoV-2 remains viable on the timescale of days on hard surfaces under ambient indoor conditions. Similarly, the virus is stable on human skin, signifying the necessity of hand hygiene amidst the current pandemic. There is an inverse relationship between SARS-CoV-2 surface persistence and temperature/humidity, and the virus is well suited to air-conditioned environments (room temperature, ~ 40% relative humidity). Sunlight may rapidly inactivate the virus, suggesting that indirect transmission predominantly occurs indoors. The development of antiviral materials and surface coatings would be an extremely effective method to mitigate the spread of COVID-19. To obtain applicable data on the persistence of coronaviruses and the efficiency of virucidal materials, future researchers should understand the common experimental limitations outlined in this review and plan their studies accordingly.
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Affiliation(s)
- Max Bueckert
- Department of Biochemistry & Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Rishi Gupta
- Department of Civil Engineering, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada;
| | - Aditi Gupta
- Mearns Centre for Learning—McPherson Library, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada;
| | - Mohit Garg
- Department of Civil Engineering, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada;
| | - Asit Mazumder
- Department of Biology, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada;
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98
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Arslan M, Xu B, Gamal El-Din M. Transmission of SARS-CoV-2 via fecal-oral and aerosols-borne routes: Environmental dynamics and implications for wastewater management in underprivileged societies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140709. [PMID: 32652357 PMCID: PMC7332911 DOI: 10.1016/j.scitotenv.2020.140709] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 05/18/2023]
Abstract
The advent of novel human coronavirus (SARS-CoV-2) and its potential transmission via fecal-oral and aerosols-borne routes are upcoming challenges to understand the fate of the virus in the environment. In this short communication, we specifically looked at the possibilities of these transmission routes based on the available literature directly related to the SARS-CoV-2 as well as on the closer phylogenetic relatives such as SARS-CoV-1. The available data suggest that, in addition to human-to-human contact, the virus may spread via fecal-oral and aerosols-borne routes. Existing knowledge states that coronaviruses have low stability in the environment due to the natural action of oxidants that disrupt the viral envelope. Previous recommended dosage of chlorination has been found to be not sufficient to inactivate SARS-CoV-2 in places where viral load is high such as hospitals and airports. Although there is no current evidence showing that coronaviruses can be transmitted through contaminated drinking water, there is a growing concern on the impact of the current pandemic wave on underprivileged societies because of their poor wastewater treatment infrastructures, overpopulation, and outbreak management strategies. More research is encouraged to trace the actual fate of SARS-CoV-2 in the environment and to develop/revise the disinfection strategies accordingly.
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Affiliation(s)
- Muhammad Arslan
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Bin Xu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Mohamed Gamal El-Din
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
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99
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Shahzamal M, Mans B, de Hoog F, Paini D, Jurdak R. Vaccination strategies on dynamic networks with indirect transmission links and limited contact information. PLoS One 2020; 15:e0241612. [PMID: 33180786 PMCID: PMC7660487 DOI: 10.1371/journal.pone.0241612] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 10/18/2020] [Indexed: 12/04/2022] Open
Abstract
Infectious diseases are still a major global burden for modern society causing 13 million deaths annually. One way to reduce the morbidity and mortality rates from infectious diseases is through pre-emptive or targeted vaccinations. Current theoretical vaccination strategies based on contact networks, however, rely on highly specific individual contact information which is difficult and costly to obtain, in order to identify influential spreading individuals. Current approaches also focus only on direct contacts between individuals for spreading, and disregard indirect transmission where a pathogen can spread between one infected individual and one susceptible individual who visit the same location within a short time-frame without meeting. This paper presents a novel vaccination strategy which relies on coarse-grained contact information, both direct and indirect, that can be easily and efficiently collected. Rather than tracking exact contact degrees of individuals, our strategy uses the types of places people visit to estimate a range of contact degrees for individuals, considering both direct and indirect contacts. We conduct extensive computer simulations to evaluate the performance of our strategy in comparison to state-of-the-art vaccination strategies. Results show that, when considering indirect links, our lower cost vaccination strategy achieves comparable performance to the contact-degree based approach and outperforms other existing strategies without requiring over-detailed information.
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Affiliation(s)
- Md Shahzamal
- Data61, CSIRO, Brisbane, Australia
- Macquarie University, Sydney, Australia
- * E-mail:
| | | | | | - Dean Paini
- Health and Biosecurity, CSIRO, Canberra, Australia
| | - Raja Jurdak
- Data61, CSIRO, Brisbane, Australia
- Queensland University of Technology, Brisbane, Australia
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100
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Otero Fernandez M, Thomas RJ, Oswin H, Haddrell AE, Reid JP. Transformative Approach To Investigate the Microphysical Factors Influencing Airborne Transmission of Pathogens. Appl Environ Microbiol 2020; 86:e01543-20. [PMID: 32978136 PMCID: PMC7657628 DOI: 10.1128/aem.01543-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/17/2020] [Indexed: 01/06/2023] Open
Abstract
Emerging outbreaks of airborne pathogenic infections worldwide, such as the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, have raised the need to understand parameters affecting the airborne survival of microbes in order to develop measures for effective infection control. We report a novel experimental strategy, TAMBAS (tandem approach for microphysical and biological assessment of airborne microorganism survival), to explore the synergistic interactions between the physicochemical and biological processes that impact airborne microbe survival in aerosol droplets. This innovative approach provides a unique and detailed understanding of the processes taking place from aerosol droplet generation through to equilibration and viability decay in the local environment, elucidating decay mechanisms not previously described. The impact of evaporation kinetics, solute hygroscopicity and concentration, particle morphology, and equilibrium particle size on airborne survival are reported, using Escherichia coli MRE162 as a benchmark system. For this system, we report that (i) particle crystallization does not directly impact microbe longevity, (ii) bacteria act as crystallization nuclei during droplet drying and equilibration, and (iii) the kinetics of size and compositional change appear to have a larger effect on microbe longevity than the equilibrium solute concentration.IMPORTANCE A transformative approach to identify the physicochemical processes that impact the biological decay rates of bacteria in aerosol droplets is described. It is shown that the evaporation process and changes in the phase and morphology of the aerosol particle during evaporation impact microorganism viability. The equilibrium droplet size was found to affect airborne bacterial viability. Furthermore, the presence of Escherichia coli MRE162 in a droplet does not affect aerosol growth/evaporation but influences the dynamic behavior of the aerosol by processing the culture medium prior to aerosolization, affecting the hygroscopicity of the culture medium; this highlights the importance of the inorganic and organic chemical composition within the aerosolized droplets that impact hygroscopicity. Bacteria also act as crystallization nuclei. The novel approach and data have implications for increased mechanistic understanding of aerosol survival and infectivity in bioaerosol studies spanning the medical, veterinary, farming, and agricultural fields, including the role of microorganisms in atmospheric processing and cloud formation.
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Affiliation(s)
| | - Richard J Thomas
- Defence Science Technology Laboratory (DSTL), Porton Down, Salisbury, United Kingdom
| | - Henry Oswin
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Allen E Haddrell
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Jonathan P Reid
- School of Chemistry, University of Bristol, Bristol, United Kingdom
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