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1.
Heliyon ; 10(15): e35092, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39170199

RESUMEN

COVID-19 has already claimed over 7 million lives and has infected over 775 million people globally [1]. SARS-CoV-2, the virus that causes Covid-19, spreads primarily through droplets from infected people's airways, rendering Heating, Ventilation, and Air Conditioning (HVAC) systems critical in controlling infection risk levels in the indoor environment. To understand the dynamics of exhaled droplets and aerosols and the percentage of particles that are inhaled, escaped, recirculated, or trapped on different surfaces for a variety of environmental settings, we have presented our findings from the Computational Fluid Dynamics (CFD) modeling to investigate the impact of changing HVAC parameters in this paper. When combined with the spatial and temporal distribution of droplets, this method can be used to assess the potential risk and strengthen resilience. This finding demonstrates the viability and usefulness of CFD for modeling the distribution and dynamics of droplets and aerosols in confined environments. Our study demonstrates that raising the Air Change per Hour (ACH) from 2 to 8 reduces the risk of particle inhalation by nearly 70 %. Additionally, limiting the amount of air recirculation or increasing the amount of fresh air helps to reduce the number of airborne particles in an indoor space. To reduce the potential for respiratory droplet-related transmission and to provide relevant recommendations to the appropriate authority, the same computational approach could be applied to a wide range of ventilated indoor environments such as public buses, restaurants, exhibitions, and theaters.

2.
J Breath Res ; 18(4)2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-38861972

RESUMEN

Diagnosing lung infections is often challenging because of the lack of a high-quality specimen from the diseased lung. Since persons with cystic fibrosis are subject to chronic lung infection, there is frequently a need for a lung specimen. In this small, proof of principle study, we determined that PneumoniaCheckTM, a non-invasive device that captures coughed droplets from the lung on a filter, might help meet this need. We obtained 10 PneumoniaCheckTMcoughed specimens and 2 sputum specimens from adult CF patients hospitalized with an exacerbation of their illness. We detected amylase (upper respiratory tract) with an enzymatic assay, surfactant A (lower respiratory tract) with an immunoassay, pathogenic bacteria by PCR, and markers of inflammation by a Luminex multiplex immunoassay. The amylase and surfactant A levels suggested that 9/10 coughed specimens were from lower respiratory tract with minimal upper respiratory contamination. The PCR assays detected pathogenic bacteria in 7 of 9 specimens and multiplex Luminex assay detected a variety of cytokines or chemokines. These data indicate that the PneumoniaCheckTMcoughed specimens can capture good quality lower respiratory tract specimens that have the potential to help in diagnosis, management and understanding of CF exacerbations and other lung disease.


Asunto(s)
Biomarcadores , Fibrosis Quística , Humanos , Fibrosis Quística/microbiología , Fibrosis Quística/diagnóstico , Biomarcadores/análisis , Adulto , Masculino , Femenino , Esputo/microbiología , Pulmón/microbiología , Adulto Joven
3.
Appl Environ Microbiol ; 90(2): e0201023, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38193683

RESUMEN

Expulsions of virus-laden aerosols or droplets from the oral and nasal cavities of an infected host are an important source of onward respiratory virus transmission. However, the presence of infectious influenza virus in the oral cavity during infection has not been widely considered, and thus, little work has explored the environmental persistence of influenza virus in oral cavity expulsions. Using the ferret model, we detected infectious virus in the nasal and oral cavities, suggesting that the virus can be expelled into the environment from both anatomical sites. We also assessed the stability of two influenza A viruses (H1N1 and H3N2) in droplets of human saliva or respiratory mucus over a range of relative humidities. We observed that influenza virus infectivity decays rapidly in saliva droplets at intermediate relative humidity, while viruses in airway surface liquid droplets retain infectivity. Virus inactivation was not associated with bulk protein content, salt content, or droplet drying time. Instead, we found that saliva droplets exhibited distinct inactivation kinetics during the wet and dry phases at intermediate relative humidity, and droplet residue morphology may lead to the elevated first-order inactivation rate observed during the dry phase. Additionally, distinct differences in crystalline structure and nanobead localization were observed between saliva and airway surface liquid droplets. Together, our work demonstrates that different respiratory fluids exhibit unique virus persistence profiles and suggests that influenza viruses expelled from the oral cavity may contribute to virus transmission in low- and high-humidity environments.IMPORTANCEDetermining how long viruses persist in the environment is important for mitigating transmission risk. Expelled infectious droplets and aerosols are composed of respiratory fluids, including saliva and complex mucus mixtures, but how well influenza viruses survive in such fluids is largely unknown. Here, we find that infectious influenza virus is present in the oral cavity of infected ferrets, suggesting that saliva-containing expulsions can play a role in onward transmission. Additionally, influenza virus in droplets composed of saliva degrades more rapidly than virus within respiratory mucus. Droplet composition impacts the crystalline structure and virus localization in dried droplets. These results suggest that viruses from distinct sites in the respiratory tract could have variable persistence in the environment, which will impact viral transmission fitness.


Asunto(s)
Subtipo H1N1 del Virus de la Influenza A , Animales , Humanos , Humedad , Subtipo H1N1 del Virus de la Influenza A/fisiología , Saliva , Subtipo H3N2 del Virus de la Influenza A/fisiología , Estaciones del Año , Hurones , Moco , Aerosoles
4.
Biophys Rev ; 15(5): 1359-1366, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37975001

RESUMEN

Influenza virus transmission is a crucial factor in understanding the spread of the virus within populations and developing effective control strategies. Studying the transmission patterns of influenza virus allows for better risk assessment and prediction of disease outbreaks. By monitoring the spread of the virus and identifying high-risk populations and geographic areas, it is possible to allocate resources more effectively, implement timely interventions, and provide targeted healthcare interventions to diminish the burden of influenza virus on vulnerable populations. Theoretical models of virus transmission are used to study and simulate of influenza virus spread within populations. These models aim to capture the complex dynamics of transmission, including factors such as population size, contact patterns, infectiousness, and susceptibility. Animal models serve as valuable tools for studying the dynamics of influenza virus transmission. This article presents a brief overview of existing research on the qualitative and quantitative study of influenza virus transmission in animal models. We discuss the methodologies employed, key insights gained from these studies, and their relevance.

5.
QRB Discov ; 4: e3, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37529032

RESUMEN

Respiratory disease and breathing abnormalities worsen with dehydration of the upper airways. We find that humidification of inhaled air occurs by evaporation of water over mucus lining the upper airways in such a way as to deliver an osmotic force on mucus, displacing it towards the epithelium. This displacement thins the periciliary layer of water beneath mucus while thickening topical water that is partially condensed from humid air on exhalation. With the rapid mouth breathing of dry air, this condensation layer, not previously reported while common to transpiring hydrogels in nature, can deliver an osmotic compressive force of up to around 100 cm H2O on underlying cilia, promoting adenosine triphosphate secretion and activating neural pathways. We derive expressions for the evolution of the thickness of the condensation layer, and its impact on cough frequency, inflammatory marker secretion, cilia beat frequency and respiratory droplet generation. We compare our predictions with human clinical data from multiple published sources and highlight the damaging impact of mouth breathing, dry, dirty air and high minute volume on upper airway function. We predict the hypertonic (or hypotonic) saline mass required to reduce (or amplify) dysfunction by restoration (or deterioration) of the structure of ciliated and condensation water layers in the upper airways and compare these predictions with published human clinical data. Preserving water balance in the upper airways appears critical in light of contemporary respiratory health challenges posed by the breathing of dirty and dry air.

6.
J Cutan Aesthet Surg ; 16(1): 55-59, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37383973

RESUMEN

The use of face mask is essential in COVID-19 era. During this period for cosmetic procedure on the face, the mask should be of small size and easily procured to maximize the exposure of the face especially in girls going to get married having hirsutism. For this purpose, the surgical mask is customized to get a small face mask.

7.
Adv Sci (Weinh) ; 10(19): e2205255, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37132608

RESUMEN

Short-range exposure to airborne virus-laden respiratory droplets is an effective transmission route of respiratory diseases, as exemplified by Coronavirus Disease 2019 (COVID-19). In order to assess the risks associated with this pathway in daily-life settings involving tens to hundreds of individuals, the chasm needs to be bridged between fluid dynamical simulations and population-scale epidemiological models. This is achieved by simulating droplet trajectories at the microscale in numerous ambient flows, coarse-graining their results into spatio-temporal maps of viral concentration around the emitter, and coupling these maps to field-data about pedestrian crowds in different scenarios (streets, train stations, markets, queues, and street cafés). At the individual scale, the results highlight the paramount importance of the velocity of the ambient air flow relative to the emitter's motion. This aerodynamic effect, which disperses infectious aerosols, prevails over all other environmental variables. At the crowd's scale, the method yields a ranking of the scenarios by the risks of new infections, dominated by the street cafés and then the outdoor market. While the effect of light winds on the qualitative ranking is fairly marginal, even the most modest air flows dramatically lower the quantitative rates of new infections.


Asunto(s)
COVID-19 , Trastornos Respiratorios , Enfermedades Respiratorias , Humanos , Aerosoles y Gotitas Respiratorias
8.
Build Simul ; 16(5): 781-794, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37101943

RESUMEN

Origin of differently sized respiratory droplets is fundamental for clarifying their viral loads and the sequential transmission mechanism of SARS-CoV-2 in indoor environments. Transient talking activities characterized by low (0.2 L/s), medium (0.9 L/s), and high (1.6 L/s) airflow rates of monosyllabic and successive syllabic vocalizations were investigated by computational fluid dynamics (CFD) simulations based on a real human airway model. SST k-ω model was chosen to predict the airflow field, and the discrete phase model (DPM) was used to calculate the trajectories of droplets within the respiratory tract. The results showed that flow field in the respiratory tract during speech is characterized by a significant laryngeal jet, and bronchi, larynx, and pharynx-larynx junction were main deposition sites for droplets released from the lower respiratory tract or around the vocal cords, and among which, over 90% of droplets over 5 µm released from vocal cords deposited at the larynx and pharynx-larynx junction. Generally, droplets' deposition fraction increased with their size, and the maximum size of droplets that were able to escape into external environment decreased with the airflow rate. This threshold size for droplets released from the vocal folds was 10-20 µm, while that for droplets released from the bronchi was 5-20 µm under various airflow rates. Besides, successive syllables pronounced at low airflow rates promoted the escape of small droplets, but do not significantly affect the droplet threshold diameter. This study indicates that droplets larger than 20 µm may entirely originate from the oral cavity, where viral loads are lower; it provides a reference for evaluating the relative importance of large-droplet spray and airborne transmission route of COVID-19 and other respiratory infections.

9.
J. Public Health Africa (Online) ; 14(12): 1-33, 2023. figures, tables
Artículo en Inglés | AIM (África) | ID: biblio-1530814

RESUMEN

Introduction: Namibia, as with many countries around the world is experiencing devastating impact of Covid-19 disease on the economy, psycho-social interactions, and well-being of the populace. These countries implemented several measures to limit the spread of the virus responsible for the severe acute respiratory syndrome (SARS-CoV-2). Namibia also put measures in place to curtail the spread and fatalities due to the virus. However, the nature and implementation strategies of Public Health regulations seriously have impact on preventing the spread and curtailing fatalities arising from the virus. Objective: This article presents a report on the effectiveness and impact of Public Health measures instituted by the Health Authority towards curtailing the scourge of covid-19 on the general populace. Method: Elements of the PRISMA protocol was utilised in the review which enabled the synthesis of data on focused area. Multifaceted databases on covid19 such as Scopus, ScienceDirect, Google Scholar, World Health Organisation and the Ministry of Health and Social Services of Namibia (MoHSS) among others was used. Result: A steady increase in covid-19 infection at an average rate of eleven (11) per day was noted in the country up till June 2021. Highest rate was linked to densely populated regions of Erongo and Khomas. Control measures for infection prevention and vaccination drive was ineffective majorly as a result of misinformation. 3


Asunto(s)
Humanos , Masculino , Femenino , Terapéutica , SARS-CoV-2 , COVID-19 , Pandemias
10.
J Public Health Afr ; 14(12): 2094, 2023 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-38269104

RESUMEN

Namibia, as with many countries around the world is experiencing devastating impact of Covid-19 disease on the economy, psycho-social interactions, and well-being of the populace. These countries implemented several measures to limit the spread of the virus responsible for the severe acute respiratory syndrome (SARS-CoV-2). Namibia also put measures in place to curtail the spread and fatalities due to the virus. However, the nature and implementation strategies of Public Health regulations seriously have impact on preventing the spread and curtailing fatalities arising from the virus. This article presents a report on the effectiveness and impact of Public Health measures instituted by the Health Authority towards curtailing the scourge of covid-19 on the general populace. Elements of the PRISMA protocol was utilised in the review which enabled the synthesis of data on focused area. Multifaceted databases on covid-19 such as Scopus, Science Direct, Google Scholar, World Health Organisation and the Ministry of Health and Social Services of Namibia (MoHSS) among others was used. A steady increase in covid-19 infection at an average rate of eleven (11) per day was noted in the country up till June 2021. Highest rate was linked to densely populated regions of Erongo and Khomas. Control measures for infection prevention and vaccination drive was ineffective majorly as a result of misinformation. A paradigm shift of enhanced interaction with local populace for effective information dissemination is required towards limiting the scourge of the virus and hence, saving of lives.

11.
China CDC Wkly ; 4(26): 565-569, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35919454

RESUMEN

What is already known about this topic?: Environmental factors such as temperature and humidity play important roles in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via droplets/aerosols. What is added by this report?: Higher relative humidity (61%-80%), longer spreading time (120 min), and greater dispersal distance (1 m) significantly reduced SARS-CoV-2 pseudovirus loads. There was an interaction effect between relative humidity and spreading time. What are the implications for public health practice?: The findings contribute to our understanding of the impact of environmental factors on the transmission of SARS-CoV-2 via airborne droplets/aerosols.

12.
Front Physiol ; 13: 923945, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35795643

RESUMEN

The recent COVID-19 pandemic has propelled the field of aerosol science to the forefront, particularly the central role of virus-laden respiratory droplets and aerosols. The pandemic has also highlighted the critical need, and value for, an information bridge between epidemiological models (that inform policymakers to develop public health responses) and within-host models (that inform the public and health care providers how individuals develop respiratory infections). Here, we review existing data and models of generation of respiratory droplets and aerosols, their exhalation and inhalation, and the fate of infectious droplet transport and deposition throughout the respiratory tract. We then articulate how aerosol transport modeling can serve as a bridge between and guide calibration of within-host and epidemiological models, forming a comprehensive tool to formulate and test hypotheses about respiratory tract exposure and infection within and between individuals.

13.
J Colloid Interface Sci ; 619: 229-245, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35397458

RESUMEN

HYPOTHESIS: The formation of virus-laden colloidal respiratory microdroplets - the sneeze or cough virulets and their evaporation driven miniaturization in the open air are found to have a significant impact on the community transmission of COVID-19 pandemic. SIMULATION DETAILS: We simulate the motions and trajectories of virulets by employing laminar fluid flow coupled with droplet tracing physics. A force field analysis has been included considering the gravity, drag, and inertial forces to unleash some of the finer features of virulet trajectories leading to the droplet and airborne transmissions of the virus. Furthermore, an analytical model corroborates temperature (T) and relative humidity (RH) controlled droplet miniaturization. RESULTS: The study elucidates that the tiny (1-50 µm) and intermediate (60-100 µm) size ranged virulets tend to form bioaerosol and facilitate an airborne transmission while the virulets of larger dimensions (300 to 500 µm) are more prone to gravity dominated droplet transmission. Subsequently, the mapping between the T and RH guided miniaturization of virulets with the COVID-19 cases for six different cities across the globe justifies the significant contribution of miniaturization-based bioaerosol formation for community transmission of the pandemic.


Asunto(s)
COVID-19 , Tos , Humanos , Pandemias , Fenómenos Físicos , Estornudo
14.
Infect Disord Drug Targets ; 22(4): e080222200919, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35135456

RESUMEN

Since the first news of a coronavirus-related pneumonia outbreak in December 2019, the virus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), which causes COVID-19, has spread worldwide, with more than 100 million people infected in over 210 countries and two million deaths. In the UK (B.1.1.7), South Africa (B.1.351), Brazil (P.1), and India (B.1.617), independent SARS-CoV-2 lineages have recently been established. The virus accesses these variants via the angiotensin- converting enzyme-2 (ACE2) receptor due to several mutations in the immune-dominant spike protein. SARS-CoV-2 has caused substantial morbidity and mortality, as well as significant strain on public health systems and the global economy, due to the severity and intensity at which it has spread. COVID-19 vaccines have shown to be highly successful in clinical trials and can be used to fight the pandemic. The COVID-19 pandemic's environmental trends change at breakneck speed, making predictions based on traditional epidemiological knowledge particularly speculative. Following the first outbreak, the second wave of COVID-19 swept across the globe, infecting various countries. The third wave of coronavirus infection has already been experienced in a few countries. Many of us have said, "When this is over," but what exactly does that mean? Since the virus's first-, second-, and third-order effects manifest over various time periods, the pandemic will not be considered 'over' until the 'third phase' of the COVID-19 pandemic has passed. It is the best time to take preventative steps and immunize ourselves with vaccines in order to prepare for the predicted third wave of COVID-19 in some countries. In order to effectively suppress and monitor the COVID-19 pandemic, early and timely measures with improved social distancing policies should be enforced. We must continue critical public health efforts to suppress transmission and reduce mortality while working toward the rollout of a safe and efficient vaccine, and we must have the patience to listen, learn, improve, innovate, and evolve.


Asunto(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiología , COVID-19/prevención & control , Vacunas contra la COVID-19 , Humanos , Pandemias/prevención & control , Salud Pública , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo
15.
Transbound Emerg Dis ; 69(2): 669-684, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33566453

RESUMEN

H9N2 influenza virus has been reported worldwide for several decades, and it has evolved into multiple genotypes among domestic poultry. However, the study involving ecology and evolution of low pathogenic avian influenza virus H9N2 in wild birds in China is limited. Here, we carried out surveillance of avian influenza virus H9N2 in wild birds along with the East Asian-Australian migratory flyway in China in 2017. To estimate the prevalence of H9N2 avian virus in wild birds, information on exposure of wild bird populations to H9N2 viruses using serology, in addition to virology, would greatly improve monitoring capabilities. In this study, we also present serological data of H9N2 among wild birds in China during 2013-2016. We report the identification of poultry-derived H9N2 isolates from asymptomatic infected multispecies wild birds such as Common kestrel (Falco tinnunculus), Northern goshawk (Accipiter gentilis), Little owl (Athene noctua) and Ring-necked Pheasant (Phasianus colchicus) in North China in June 2017. Phylogenetic analysis demonstrated that Tianjin H9N2 isolates belong to the G81 and carry internal genes highly homologous to human H10N8 and H7N9. The isolates could directly infect mice without adaptation but were restricted to replicate in the respiratory system. Glycan-binding preference analyses suggested that the H9N2 isolates have acquired a binding affinity for the human-like receptor. Notably, results from transmission experiment in guinea pigs and ferrets demonstrated the wild birds-derived H9N2 influenza virus exhibits efficient transmission phenotypes in mammalian models via respiratory droplets. Our results indicate that the H9N2 AIVs continued to circulate extensively in wild bird populations and migratory birds play an important role in the spread and genetic diversification of H9N2 AIVs. The pandemic potential of H9N2 viruses demonstrated by aerosol transmission in mammalian models via respiratory droplets highlights the importance of monitoring influenza viruses in these hosts.


Asunto(s)
Subtipo H7N9 del Virus de la Influenza A , Subtipo H9N2 del Virus de la Influenza A , Gripe Aviar , Enfermedades de los Roedores , Animales , Australia , Aves , China/epidemiología , Hurones , Cobayas , Humanos , Subtipo H7N9 del Virus de la Influenza A/genética , Subtipo H9N2 del Virus de la Influenza A/genética , Mamíferos , Ratones , Filogenia , Aves de Corral , Aerosoles y Gotitas Respiratorias
16.
Sensors (Basel) ; 21(21)2021 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-34770529

RESUMEN

Contamination inspection is an ongoing concern for food distributors, restaurant owners, caterers, and others who handle food. Food contamination must be prevented, and zero tolerance legal requirements and damage to the reputation of institutions or restaurants can be very costly. This paper introduces a new handheld fluorescence-based imaging system that can rapidly detect, disinfect, and document invisible organic residues and biofilms which may host pathogens. The contamination, sanitization inspection, and disinfection (CSI-D) system uses light at two fluorescence excitation wavelengths, ultraviolet C (UVC) at 275 nm and violet at 405 nm, for the detection of organic residues, including saliva and respiratory droplets. The 275 nm light is also utilized to disinfect pathogens commonly found within the contaminated residues. Efficacy testing of the neutralizing effects of the ultraviolet light was conducted for Aspergillus fumigatus, Streptococcus pneumoniae, and the influenza A virus (a fungus, a bacterium, and a virus, respectively, each commonly found in saliva and respiratory droplets). After the exposure to UVC light from the CSI-D, all three pathogens experienced deactivation (> 99.99%) in under ten seconds. Up to five-log reductions have also been shown within 10 s of UVC irradiation from the CSI-D system.


Asunto(s)
Desinfección , Rayos Ultravioleta , Biopelículas , Hongos , Imagen Óptica
17.
Best Pract Res Clin Anaesthesiol ; 35(3): 269-292, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34511219

RESUMEN

Coronaviruses belong to the family Coronaviridae order Nidovirales and are known causes of respiratory and intestinal disease in various mammalian and avian species. Species of coronaviruses known to infect humans are referred to as human coronaviruses (HCoVs). While traditionally, HCoVs have been a significant cause of the common cold, more recently, emergent viruses, including severe acute respiratory syndrome coronavirus (SARS-CoV-2) has caused a global pandemic. Here, we discuss coronavirus disease (COVID-19) biology, pathology, epidemiology, signs and symptoms, diagnosis, treatment, and recent clinical trials involving promising treatments.


Asunto(s)
Antivirales/administración & dosificación , COVID-19/epidemiología , COVID-19/terapia , SARS-CoV-2 , Adenosina Monofosfato/administración & dosificación , Adenosina Monofosfato/análogos & derivados , Corticoesteroides/administración & dosificación , Alanina/administración & dosificación , Alanina/análogos & derivados , Animales , COVID-19/diagnóstico , COVID-19/inmunología , Coronavirus/efectos de los fármacos , Coronavirus/inmunología , Tos/epidemiología , Tos/terapia , Diabetes Mellitus/epidemiología , Diabetes Mellitus/terapia , Fatiga/epidemiología , Fatiga/terapia , Fiebre , Cardiopatías/epidemiología , Cardiopatías/terapia , Humanos , Respiración con Presión Positiva/métodos , Pronóstico , Enfermedad Pulmonar Obstructiva Crónica/epidemiología , Enfermedad Pulmonar Obstructiva Crónica/terapia , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/inmunología , Resultado del Tratamiento
18.
ACS Nano ; 15(9): 14049-14060, 2021 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-34339604

RESUMEN

Evaporation-induced particle aggregation in drying droplets is of significant importance in the prevention of pathogen transfer due to the possibility of indirect fomite transmission of the infectious virus particles. In this study, particle aggregation was directionally controlled using contact line dynamics (pinned or slipping) and geometrical gradients on microstructured surfaces by the systematic investigation of the evaporation process on sessile droplets and sprayed microdroplets laden with virus-simulant nanoparticles. Using this mechanism, we designed robust particle capture surfaces by significantly inhibiting the contact transfer of particles from fomite surfaces. For the proof-of-concept, interconnected hexagonal and inverted pyramidal microwall were fabricated using ultraviolet-based nanoimprint lithography, which is considered to be a promising scalable manufacturing process. We demonstrated the potentials of an engineered microcavity surface to limit the contact transfer of particle aggregates deposited with the evaporation of microdroplets by 93% for hexagonal microwall and by 96% for inverted pyramidal microwall. The particle capture potential of the interconnected microstructures was also investigated using biological particles, including adenoviruses and lung-derived extracellular vesicles. The findings indicate that the proposed microstructured surfaces can reduce the indirect fomite transmission of highly infectious agents, including norovirus, rotavirus, or SARS-CoV-2, via respiratory droplets.


Asunto(s)
COVID-19 , Fómites , Humanos , SARS-CoV-2
19.
J Occup Environ Hyg ; 18(8): 394-408, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34161194

RESUMEN

SARS-CoV-2 and other microbes within aerosol particles can be partially shielded from UV radiation. The particles refract and absorb light, and thereby reduce the UV intensity at various locations within the particle. Previously, we demonstrated shielding in calculations of UV intensities within spherical approximations of SARS-CoV-2 virions within spherical particles approximating dried-to-equilibrium respiratory fluids. The purpose of this paper is to extend that work to survival fractions of virions (i.e., fractions of virions that can infect cells) within spherical particles approximating dried respiratory fluids, and to investigate the implications of these calculations for using UV light for disinfection. The particles may be on a surface or in air. Here, the survival fraction (S) of a set of individual virions illuminated with a UV fluence (F, in J/m2) is assumed described by S(kF) = exp(-kF), where k is the UV inactivation rate constant (m2/J). The average survival fraction (Sp) of the simulated virions in a group of particles is calculated using the energy absorbed by each virion in the particles. The results show that virions within particles of dried respiratory fluids can have larger Sp than do individual virions. For individual virions, and virions within 1-, 5-, and 9-µm particles illuminated (normal incidence) on a surface with 260-nm UV light, the Sp = 0.00005, 0.0155, 0.22, and 0.28, respectively, when kF = 10. The Sp decrease to <10-7, <10-7, 0.077, and 0.15, respectively, for kF = 100. Results also show that illuminating particles with UV beams from widely separated directions can strongly reduce the Sp. These results suggest that the size distributions and optical properties of the dried particles of virion-containing respiratory fluids are likely important to effectively designing and using UV germicidal irradiation systems for microbes in particles. The results suggest the use of reflective surfaces to increase the angles of illumination and decrease the Sp. The results suggest the need for measurements of the Sp of SARS-CoV-2 in particles having compositions and sizes relevant to the modes of disease transmission.


Asunto(s)
Secreciones Corporales/efectos de la radiación , Secreciones Corporales/virología , SARS-CoV-2/efectos de la radiación , Rayos Ultravioleta , Virión/efectos de la radiación , Aerosoles , Microbiología del Aire , COVID-19/virología , Simulación por Computador , Tos/virología , Desinfección/métodos , Humanos , Estornudo
20.
Indoor Air ; 31(6): 1860-1873, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34096643

RESUMEN

The SARS-CoV-2 pandemic has created a great demand for a better understanding of the spread of viruses in indoor environments. A novel measurement system consisting of one portable aerosol-emitting mannequin (emitter) and a number of portable aerosol-absorbing mannequins (recipients) was developed that can measure the spread of aerosols and droplets that potentially contain infectious viruses. The emission of the virus from a human is simulated by using tracer particles solved in water. The recipients inhale the aerosols and droplets and quantify the level of solved tracer particles in their artificial lungs simultaneously over time. The mobile system can be arranged in a large variety of spreading scenarios in indoor environments and allows for quantification of the infection probability due to airborne virus spreading. This study shows the accuracy of the new measurement system and its ability to compare aerosol reduction measures such as regular ventilation or the use of a room air purifier.


Asunto(s)
Aerosoles/análisis , Filtros de Aire , Contaminación del Aire Interior , Contaminación del Aire Interior/análisis , COVID-19 , Humanos , SARS-CoV-2
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