Stability of influenza A virus in droplets and aerosols is heightened by the presence of commensal respiratory bacteria

Journal of Virology, Год журнала: 2024, Номер 98(7)

Опубликована: Июнь 13, 2024

ABSTRACT Aerosol transmission remains a major challenge for control of respiratory viruses, particularly those causing recurrent epidemics, like influenza A virus (IAV). These viruses are rarely expelled alone, but instead embedded in consortium microorganisms that populate the tract. The impact microbial communities and inter-pathogen interactions upon stability transmitted is well-characterized enteric pathogens, under-studied niche. Here, we assessed whether presence five different species commensal bacteria could influence persistence IAV within phosphate-buffered saline artificial saliva droplets deposited on surfaces at typical indoor air humidity, airborne aerosol particles. In droplets, individual or mixed bacterial community resulted 10- to 100-fold more infectious remaining after 1 h, due bacterial-mediated flattening drying early efflorescence. Even when no efflorescence occurred high humidity bacteria-induced changes droplet morphology were abolished by aerosolization deposition well plate, remained protective. Staphylococcus aureus Streptococcus pneumoniae most stabilizing compared other commensals equivalent density, indicating composition an individual’s microbiota previously unconsidered factor influencing persistence. IMPORTANCE It known infections such as coronavirus disease 2019 release virus-containing aerosols larger infected host. survival time into environment can vary depending temperature, room UV exposure, composition, suspending fluid. However, few studies consider fact not alone tract—we constantly colonized plethora our noses, mouth, lower system. gut, be stabilized against inactivation environmental decay gut bacteria. Despite similarly complex tract, have investigated viral stabilization occur this address question investigating range systems representing droplets.

Язык: Английский

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Airborne Transmission of SARS-CoV-2: The Contrast between Indoors and Outdoors

Fluids, Год журнала: 2024, Номер 9(3), С. 54 - 54

Опубликована: Фев. 22, 2024

COVID-19 is an airborne disease, with the vast majority of infections occurring indoors. In comparison, little transmission occurs outdoors. Here, we investigate pathways that differentiate indoors from outdoors and conclude profound differences exist, which help to explain why SARS-CoV-2 much more prevalent Near- far-field are discussed along factors affect infection risk, aerosol concentration, air entrainment, thermal plumes, occupancy duration all identified as being influential. particular, present fundamental equations underpin Wells–Riley model show mathematical relationship between inhaled virus particles quanta infection. A simple also presented for assessing risk in spaces incomplete mixing. Transmission assessed terms concentration using 1D equations, followed by a description plume–ceiling interactions. With respect this, new experimental results Schlieren visualisation computational fluid dynamics (CFD) based on Eulerian–Lagrangian approach. Pathways discussed, key contribution exhalation plumes evaluated, presence near-field/far-field feedback loop postulated, absent

Язык: Английский

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Inactivation of virions in host particles in air using 222- and 254-nm UV: Dependence of shielding on particle size and UV wavelength

Aerosol Science and Technology, Год журнала: 2024, Номер 58(5), С. 512 - 535

Опубликована: Март 8, 2024

UV light at 222 nm inactivates SARS-CoV-2 virions intensities appearing to be benign skin and eyes. It can disinfect air without requiring protection of persons from as is needed longer wavelengths. The lower risk damage 222-nm results enhanced absorption this in the outermost parts eyes skin. Microbes partially shielded 250- 285-nm when host particles. Does higher increase shielding microbes within particles, if so, what extent? We use literature values approximate compositions optical properties four types fluids respiratory tract mouth. model spherical particles (homogeneous except for virions), calculate absorbed by virions, these survival fractions (Sp). find that relatively small generated quiet breathing (typically 1.5-µm or smaller). For larger increases host-particle diameter increases. Shielding greater 222- than 254-nm all pairs UV-fluence particle-diameters calculated. eye-safety thresholds allow fluences shorter inactivation times. Because size increases, because significant airborne disease-transmitting have >1.5-µm, it appears sizes must considered designing verifying systems such

Язык: Английский

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Relationship between indoor and outdoor temperature and humidity in a residential building in Central Europe

Discover Environment, Год журнала: 2024, Номер 2(1)

Опубликована: Июнь 9, 2024

Abstract Relative humidity and temperature in indoor spaces are two important environmental factors that not only determine the behaviour well-being of building occupants but also influence airborne transmission respiratory diseases closed spaces. While recent studies have examined how well conditions relate to outdoor ambient weather, most on weather-related health effects still use a single central site monitor such as weather station since values more convenient measure. However, correlation between is always straightforward. Our case study explores relationships residential apartment temperate climate Central Europe. Measurements performed over period one year allow for detailed comparison analysis correlations both daily averages profiles variables. The results this add further evidence observations day-to-day variation relative well-represented by measurements. It adds growing body data variables should thus prove useful aiming examining these occupants.

Язык: Английский

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Understanding Observed Trends in Moist Heatwaves in Urban Areas of South Asia and Middle East and North Africa (MENA) Regions

Lecture notes in civil engineering, Год журнала: 2025, Номер unknown, С. 357 - 371

Опубликована: Янв. 1, 2025

Язык: Английский

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Top and Side Leakage Effects on Thermoregulation and Moisture Retention with Facemask Wearing

Journal of Respiration, Год журнала: 2025, Номер 5(2), С. 5 - 5

Опубликована: Апрель 3, 2025

Background/Objectives: Mask-wearing-induced discomfort often leads to unconscious loosening of the mask relieve discomfort, thereby compromising protective efficacy. This study investigated how leakage flows affect mask-associated thermoregulation and vapor trapping inform better designs. An integrated ambience–mask–face–airway model with various mask-wearing misfits was developed. Methods: The transient warming/cooling effects, thermal buoyancy force, tissue heat generation, phase change, fluid/heat/mass transfer through a porous medium were considered in this model, which validated using Schlieren imaging, camera, velocity/temperature measurements. Leakages from top side analyzed comparison no-leak scenario under cyclic respiration conditions. Results: A significant inverse relationship observed between facial temperature/humidity. equivalent impact forces exhalation flow inertia both experimentally numerically, indicating delicate balance natural convection forced convection, is sensitive critical thermo-humidity regulation. For given gap, fraction not constant within one breathing cycle but constantly increased during exhalation. Persistently higher temperatures found nose region throughout sealed mitigated inhalation when gaps present. Vapor condensation occurred all cases. Conclusions: temporal variation profiles location highlighting feasibility leveraging temperature relative humidity test fit quantify fraction.

Язык: Английский

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Identifying outbreak risk factors through case-controls comparisons

Communications Medicine, Год журнала: 2025, Номер 5(1)

Опубликована: Май 30, 2025

Язык: Английский

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A study on passenger flow model and simulation in aspect of COVID-19 spreading on public transport bus stops

Journal of Public Transportation, Год журнала: 2023, Номер 25, С. 100063 - 100063

Опубликована: Янв. 1, 2023

Public transport during COVID-19 has been crucial in ensuring the safety and health of both passengers staff while maintaining essential public services. Currently is gradually resuming its operations, pandemic's influence expected to persist for a long time. The vast majority studies this aspect concern likelihood spreading virus inside means travel. Nevertheless, there exists substantial body articles addressing manner which passenger movement within systems impacted by concerns altered satisfaction levels following propagation pandemic. This paper presents model that accurately represents how move through different parts system, such as bus or train station stops. takes into account factors like it board exit vehicle, they stops, their movements are affected crowding delays. To reduce risk transmission on focused stops areas, research formulated flow using simulation programs PTV Vissim FlexSim with assumptions minimum distance concept area cross sections. These were used simulate exchange scenarios, data collected from real data. aimed develop could infection. By understanding interact we can implement effective measures minimize spread other infectious diseases.

Язык: Английский

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Airborne Transmission of SARS-CoV-2: The Contrast between Indoors and Outdoors

Опубликована: Янв. 11, 2024

Covid-19 is an airborne disease, with the vast majority of infections occurring indoors. By comparison, little transmission occurs outdoors. Here, we investigate pathways that differentiate indoors from outdoors, and conclude profound differences exist, which help to explain why SARS-CoV-2 much more prevalent Near far-field are discussed along factors affect infection risk, aerosol concentration, air entrainment, thermal plumes, occupancy duration all identified as being influential. In particular, present fundamental equations underpin Wells-Riley model, show mathematical relationship between inhaled virus particles quanta infection. A simple model also presented for assessing risk in spaces incomplete mixing. Transmission assessed terms concentration using 1D equations, followed by a description plume-ceiling interactions. With respect this, new experimental results Schlieren-visualisation Computational Fluid Dynamics (CFD) based on Eulerian-Lagrangian approach. Pathways discussed, key contribution exhalation plumes evaluated, presence near-field/far-field feedback loop postulated, absent

Язык: Английский

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Effects of Strain Differences, Humidity Changes, and Saliva Contamination on the Inactivation of SARS-CoV-2 by Ion Irradiation

Viruses, Год журнала: 2024, Номер 16(4), С. 520 - 520

Опубликована: Март 28, 2024

One of the methods to inactivate viruses is denature viral proteins using released ions. However, there have been no reports detailing effects changes in humidity or contamination with body fluids on inactivation viruses. This study investigated and saliva efficacy SARS-CoV-2 ions multiple strains. Virus solutions different infectious titers were dropped onto a circular nitrocellulose membrane irradiated from 10 cm above membrane. After irradiation for 60, 90, 120 min, measured. The effect virus under conditions was also examined containing 90% mixtures collected people. A decrease infectivity observed over time all strains, but ion further accelerated infectivity. Ion can at 80% humidity, did not appear until 90 min after irradiation. presence protected drying maintained infectiousness longer period compared saliva. In particular, Omicron strain retained its titer than other demonstrated consistent reduction number when control across varying levels periods. underscores notable effectiveness irradiation, even as modest 50%, thereby emphasizing crucial role mitigating rapid dissemination SARS-CoV-2.

Язык: Английский

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