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1.
J Hazard Mater ; 421: 126799, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34396958

RESUMO

Stack aerosols are generated within vertical building drainage stacks during the discharge of wastewater containing feces and exhaled mucus from toilets and washbasins. Fifteen stack aerosol-related outbreaks of coronavirus disease 2019 (COVID-19) in high-rise buildings have been observed in Hong Kong and Guangzhou. Currently, we investigated two such outbreaks of COVID-19 in Hong Kong, identified the probable role of chimney effect-induced airflow in a building drainage system in the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We injected tracer gas (SF6) into the drainage stacks via the water closet of the index case and monitored tracer gas concentrations in the bathrooms and along the facades of infected and non-infected flats and in roof vents. The air temperature, humidity, and pressure in vertical stacks were also monitored. The measured tracer gas distribution agreed with the observed distribution of the infected cases. Phylogenetic analysis of the SARS-CoV-2 genome sequences demonstrated clonal spread from a point source in cases along the same vertical column. The stack air pressure and temperature distributions suggested that stack aerosols can spread to indoors through pipe leaks which provide direct evidence for the long-range aerosol transmission of SARS-CoV-2 through drainage pipes via the chimney effect.


Assuntos
Aerossóis , Microbiologia do Ar , COVID-19 , Habitação , COVID-19/transmissão , Hong Kong , Humanos , Filogenia , SARS-CoV-2
2.
Environ Sci Process Impacts ; 23(11): 1681-1687, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34596193

RESUMO

Indoor flooding is a leading contributor to indoor dampness and the associated mold infestations in the coastal United States. Whether the prevalent mold genera that infest the coastal flood-prone buildings are different from those not flood-prone is unknown. In the current case study of 28 mold-infested buildings across the U.S. east coast, we surprisingly noted a trend of higher prevalence of indoor Aspergillus and Penicillium genera (denoted here as Asp-Pen) in buildings with previous flooding history. Hence, we sought to determine the possibility of a potential statistically significant association between indoor Asp-Pen prevalence and three building-related variables: (i) indoor flooding history, (ii) geographical location, and (iii) the building's use (residential versus non-residential). Culturable spores and hyphal fragments in indoor air were collected using the settle-plate method, and corresponding genera were confirmed using phylogenetic analysis of their ITS sequence (the fungal barcode). Analysis of variance (ANOVA) using Generalized linear model procedure (GLM) showed that Asp-Pen prevalence is significantly associated with indoor flooding as well as coastal proximity. To address the small sample size, a multivariate decision tree analysis was conducted, which ranked indoor flooding history as the strongest determinant of Asp-Pen prevalence, followed by geographical location and the building's use.


Assuntos
Poluição do Ar em Ambientes Fechados , Penicillium , Microbiologia do Ar , Poluição do Ar em Ambientes Fechados/análise , Aspergillus , Inundações , Fungos , Filogenia , Prevalência
3.
PLoS Comput Biol ; 17(10): e1009474, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34662342

RESUMO

The role of heating, ventilation, and air-conditioning (HVAC) systems in the transmission of SARS-CoV-2 is unclear. To address this gap, we simulated the release of SARS-CoV-2 in a multistory office building and three social gathering settings (bar/restaurant, nightclub, wedding venue) using a well-mixed, multi-zone building model similar to those used by Wells, Riley, and others. We varied key factors of HVAC systems, such as the Air Changes Per Hour rate (ACH), Fraction of Outside Air (FOA), and Minimum Efficiency Reporting Values (MERV) to examine their effect on viral transmission, and additionally simulated the protective effects of in-unit ultraviolet light decontamination (UVC) and separate in-room air filtration. In all building types, increasing the ACH reduced simulated infections, and the effects were seen even with low aerosol emission rates. However, the benefits of increasing the fraction of outside air and filter efficiency rating were greatest when the aerosol emission rate was high. UVC filtration improved the performance of typical HVAC systems. In-room filtration in an office setting similarly reduced overall infections but worked better when placed in every room. Overall, we found little evidence that HVAC systems facilitate SARS-CoV-2 transmission; most infections in the simulated office occurred near the emission source, with some infections in individuals temporarily visiting the release zone. HVAC systems only increased infections in one scenario involving a marginal increase in airflow in a poorly ventilated space, which slightly increased the likelihood of transmission outside the release zone. We found that improving air circulation rates, increasing filter MERV rating, increasing the fraction of outside air, and applying UVC radiation and in-room filtration may reduce SARS-CoV-2 transmission indoors. However, these mitigation measures are unlikely to provide a protective benefit unless SARS-CoV-2 aerosol emission rates are high (>1,000 Plaque-forming units (PFU) / min).


Assuntos
Ar Condicionado , COVID-19/transmissão , Calefação , SARS-CoV-2 , Ventilação , Aerossóis , Microbiologia do Ar , Movimentos do Ar , COVID-19/prevenção & controle , COVID-19/virologia , Biologia Computacional , Simulação por Computador , Humanos , Modelos Biológicos , Pandemias , SARS-CoV-2/efeitos da radiação , Interação Social , Raios Ultravioleta , Local de Trabalho
4.
Artigo em Inglês | MEDLINE | ID: mdl-34639680

RESUMO

Multiple studies have demonstrated the presence of microorganisms commonly associated with surgical site infections (SSIs), in the air within the operating theatre (OT). In some countries such Italy, the limit of microbial concentration in the air for OT with turbulent airflows is 35 CFU/m3 for an empty OT and 180 CFU/m3 during activity. This study aims to hypothesize new benchmarks for the airborne microbial load in turbulent airflow operating theatres in operational and at rest conditions using the percentile distribution of data through a 17-year environmental monitoring campaign in various Italian hospitals that implemented a continuous quality improvement policy. The quartile distribution analysis has shown how in operational and at rest conditions, 75% of the values were below 110 CFU/m3 and 18 CFU/m3, respectively, which can be considered a new benchmark for the monitored OTs. During the initial stages of the monitoring campaign, 28.14% of the concentration values in operational conditions and 29.29% of the values in at rest conditions did not conform to the Italian guidelines' reference values. In contrast, during the last 5 years, all values in both conditions conformed to the reference values and 98.94% of these values were below the new benchmarks. Continuous improvement has allowed contamination to be reduced to levels well below the current reference values.


Assuntos
Microbiologia do Ar , Ventilação , Benchmarking , Monitoramento Ambiental , Humanos , Salas Cirúrgicas , Infecção da Ferida Cirúrgica
5.
Sci Rep ; 11(1): 21284, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34711888

RESUMO

We quantified the presence of SARS-CoV-2 RNA in the air of different hospital settings and the autopsy room of the largest medical centre in Sao Paulo, Brazil. Real-time reverse-transcription PCR was used to determine the presence of the envelope protein of SARS-CoV-2 and the nucleocapsid protein genes. The E-gene was detected in 5 out of 6 samples at the ICU-COVID-19 ward and in 5 out of 7 samples at the ward-COVID-19. Similarly, in the non-dedicated facilities, the E-gene was detected in 5 out of 6 samples collected in the ICU and 4 out of 7 samples in the ward. In the necropsy room, 6 out of 7 samples were positive for the E-gene. When both wards were compared, the non-COVID ward presented a significantly higher concentration of the E-gene than in the COVID-19 ward (p = 0.003). There was no significant difference in E-gene concentration between the ICU-COVID-19 and the ICU (p = 0.548). Likewise, there was no significant difference among E-gene concentrations found in the autopsy room versus the ICUs and wards (dedicated or not) (p = 0.245). Our results show the widespread presence of aerosol contamination in different hospital units.


Assuntos
Microbiologia do Ar , COVID-19/virologia , Hospitais , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Aerossóis , Autopsia , Brasil/epidemiologia , COVID-19/epidemiologia , COVID-19/transmissão , Teste de Ácido Nucleico para COVID-19 , Genoma Viral , Unidades Hospitalares , Humanos , Unidades de Terapia Intensiva , Pandemias , Serviço Hospitalar de Patologia , RNA Viral/análise , RNA Viral/genética , Vírion/genética , Vírion/isolamento & purificação
6.
Waste Manag ; 136: 11-17, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34634566

RESUMO

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.


Assuntos
Microbiologia do Ar , Fungos , Bactérias , Alemanha , Hospitais Universitários , Humanos
7.
Sci Rep ; 11(1): 19910, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620887

RESUMO

Face masks are a primary preventive measure against airborne pathogens. Thus, they have become one of the keys to controlling the spread of the COVID-19 virus. Common examples, including N95 masks, surgical masks, and face coverings, are passive devices that minimize the spread of suspended pathogens by inserting an aerosol-filtering barrier between the user's nasal and oral cavities and the environment. However, the filtering process does not adapt to changing pathogen levels or other environmental factors, which reduces its effectiveness in real-world scenarios. This paper addresses the limitations of passive masks by proposing ADAPT, a smart IoT-enabled "active mask". This wearable device contains a real-time closed-loop control system that senses airborne particles of different sizes near the mask by using an on-board particulate matter (PM) sensor. It then intelligently mitigates the threat by using mist spray, generated by a piezoelectric actuator, to load nearby aerosol particles such that they rapidly fall to the ground. The system is controlled by an on-board micro-controller unit that collects sensor data, analyzes it, and activates the mist generator as necessary. A custom smartphone application enables the user to remotely control the device and also receive real-time alerts related to recharging, refilling, and/or decontamination of the mask before reuse. Experimental results on a working prototype confirm that aerosol clouds rapidly fall to the ground when the mask is activated, thus significantly reducing PM counts near the user. Also, usage of the mask significantly increases local relative humidity levels.


Assuntos
COVID-19/prevenção & controle , Exposição por Inalação/prevenção & controle , Máscaras , Material Particulado/isolamento & purificação , Dispositivos de Proteção Respiratória , SARS-CoV-2/isolamento & purificação , Aerossóis/isolamento & purificação , Microbiologia do Ar , Desenho de Equipamento , Filtração/instrumentação , Humanos , Aplicativos Móveis , Tamanho da Partícula , Materiais Inteligentes/química , Smartphone
8.
Sci Rep ; 11(1): 19930, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620923

RESUMO

Transmission of SARS-CoV-2 by aerosols has played a significant role in the rapid spread of COVID-19 across the globe. Indoor environments with inadequate ventilation pose a serious infection risk. Whilst vaccines suppress transmission, they are not 100% effective and the risk from variants and new viruses always remains. Consequently, many efforts have focused on ways to disinfect air. One such method involves use of minimally hazardous 222 nm far-UVC light. Whilst a small number of controlled experimental studies have been conducted, determining the efficacy of this approach is difficult because chamber or room geometry, and the air flow within them, influences both far-UVC illumination and aerosol dwell times. Fortunately, computational multiphysics modelling allows the inadequacy of dose-averaged assessment of viral inactivation to be overcome in these complex situations. This article presents the first validation of the WYVERN radiation-CFD code for far-UVC air-disinfection against survival fraction measurements, and the first measurement-informed modelling approach to estimating far-UVC susceptibility of viruses in air. As well as demonstrating the reliability of the code, at circa 70% higher, our findings indicate that aerosolized human coronaviruses are significantly more susceptible to far-UVC than previously thought.


Assuntos
Coronavirus Humano 229E/efeitos da radiação , Infecções por Coronavirus/prevenção & controle , Coronavirus Humano OC43/efeitos da radiação , Desinfecção/métodos , Raios Ultravioleta , Inativação de Vírus/efeitos da radiação , Aerossóis/isolamento & purificação , Microbiologia do Ar , COVID-19/prevenção & controle , Simulação por Computador , Coronavirus Humano 229E/isolamento & purificação , Coronavirus Humano 229E/fisiologia , Coronavirus Humano OC43/isolamento & purificação , Coronavirus Humano OC43/fisiologia , Desinfecção/instrumentação , Desenho de Equipamento , Humanos , Modelos Biológicos
9.
Sci Rep ; 11(1): 19403, 2021 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-34593891

RESUMO

The ongoing worldwide outbreak of COVID-19 has set personal protective equipment in the spotlight. A significant number of countries impose the use of facemasks in public spaces and encourage it in the private sphere. Even in countries where relatively high vaccination rates are achieved at present, breakthrough infections have been frequently reported and usage of facemasks in certain settings has been recommended again. Alternative solutions, including community masks fabricated using various materials, such as cotton or jersey, have emerged alongside facemasks following long-established standards (e.g., EN 149, EN 14683). In the present work, we present a computational model to calculate the ability of different types of facemasks to reduce the exposure to virus-laden respiratory particles, with a focus on the relative importance of the filtration properties and the fitting on the wearer's face. The model considers the facemask and the associated leakage, the transport of respiratory particles and their accumulation around the emitter, as well as the fraction of the inhaled particles deposited in the respiratory system. Different levels of leakages are considered to represent the diversity of fittings likely to be found among a population of non-trained users. The leakage prevails over the filtration performance of a facemask in determining the exposure level, and the ability of a face protection to limit leakages needs to be taken into account to accurately estimate the provided protection. Filtering facepieces (FFP) provide a better protection efficiency than surgical and community masks due to their higher filtration efficiency and their ability to provide a better fit and thus reduce the leakages. However, an improperly-fitted FFP mask loses a critical fraction of its protection efficiency, which may drop below the protection level provided by properly-worn surgical and community masks.


Assuntos
COVID-19/prevenção & controle , COVID-19/transmissão , Filtração/instrumentação , Máscaras/normas , SARS-CoV-2 , Aerossóis , Microbiologia do Ar , COVID-19/virologia , Transmissão de Doença Infecciosa/prevenção & controle , Filtração/normas , Humanos , Exposição por Inalação/prevenção & controle , Modelos Teóricos , Tamanho da Partícula
10.
Obstet Gynecol ; 138(4): 616-621, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34623073

RESUMO

OBJECTIVE: To characterize respiratory emissions produced during labor and vaginal delivery vis-à-vis the potential for transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: Observational study of three women who tested negative for SARS-CoV-2 and had uncomplicated vaginal deliveries. Using background-oriented schlieren imaging, we evaluated the propagation of respiratory emissions produced during the labor course and delivery. The primary outcome was the speed and propagation of breath over time, calculated through processed images collected throughout labor and delivery. RESULTS: In early labor with regular breathing, the speed of the breath was 1.37 meters/s (range 1.20-1.55 meters/s). The breath appeared to propagate faster with a cough during early labor at a speed of 1.69 meters/s (range 1.22-2.27 meters/s). During the second stage of labor with Valsalva and forced expiration, the propagation speed was 1.79 meters/s (range 1.71-1.86 meters/s). CONCLUSION: Labor and vaginal delivery increase the propagation of respiratory emissions that may increase risk of respiratory transmission of SARS-CoV-2.


Assuntos
Microbiologia do Ar , COVID-19/transmissão , Exposição por Inalação/análise , Trabalho de Parto/fisiologia , Respiração , Adulto , Parto Obstétrico/métodos , Transmissão de Doença Infecciosa , Feminino , Humanos , Gravidez , SARS-CoV-2 , Vagina , Adulto Jovem
11.
Phys Rev Lett ; 127(9): 094501, 2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34506163

RESUMO

Turbulent puffs are ubiquitous in everyday life phenomena. Understanding their dynamics is important in a variety of situations ranging from industrial processes to pure and applied science. In all these fields, a deep knowledge of the statistical structure of temperature and velocity space-time fluctuations is of paramount importance to construct models of chemical reaction (in chemistry) and of condensation of virus-containing droplets (in virology and/or biophysics) and optimal mixing strategies in industrial applications. As a matter of fact, results of turbulence in a puff are confined to bulk properties (i.e., average puff velocity and typical decay or growth time) and date back to the second half of the 20th century. There is, thus, a huge gap to fill to pass from bulk properties to two-point statistical observables. Here, we fill this gap by exploiting theory and numerics in concert to predict and validate the space-time scaling behaviors of both velocity and temperature structure functions including intermittency corrections. Excellent agreement between theory and simulations is found. Our results are expected to have a profound impact on developing evaporation models for virus-containing droplets carried by a turbulent puff, with benefits to the comprehension of the airborne route of virus contagion.


Assuntos
Modelos Biológicos , Modelos Teóricos , Microbiologia do Ar , Fenômenos Biofísicos , COVID-19/transmissão , COVID-19/virologia
12.
Rev Chilena Infectol ; 38(3): 324-332, 2021 Jun.
Artigo em Espanhol | MEDLINE | ID: mdl-34479287

RESUMO

BACKGROUND: Indoor air quality in health centers is essential to protect the health of people. In Chile, the Community Family Health Centers (CECOSF) are places with large attendance of people, favoring the dissemination of microorganisms, and there are no reports of the microbial air loading these health centers. AIM: To evaluate the microbiological indoor air quality in CECOSF-Centinela in Talcahuano, Biobío Region. METHODS: Air samples were taken in 6 rooms of the CECOSF, every 15 days between July 2018 and June 2019, with the MAS-100 NT equipment using trypticase and Sabouraud agars. Different morphotypes of bacteria and fungi were identified by PCR. RESULTS: The bacterial and fungal counts varied between 9.1 × 101 - 2.4 × 103 cfu/m3 and 10 - 1.5 × 102 cfu/m3, respectively. The air in the waiting room presented the highest counts, both for bacteria and fungi (P < 0.05). Staphylococcus, Enterococcus, Pseudomonas, Acinetobacter were identified, highlighting the species Staphylococcus aureus and Pseudomonas oryzihabitans, the latter described as a nosocomial pathogen. Among the fungi, Aspergillus, Meyerozyma and Rhodotorula were identified. CONCLUSION: The indoor air of the CECOSF-Centinela presents microorganisms of importance in human health. Therefore, it is necessary to formulate more regular monitoring programs for the control of air quality inside these health centers.


Assuntos
Poluição do Ar em Ambientes Fechados , Saúde da Família , Microbiologia do Ar , Poluição do Ar em Ambientes Fechados/análise , Chile , Contagem de Colônia Microbiana , Monitoramento Ambiental , Fungos , Humanos , Pseudomonas
13.
J Environ Sci (China) ; 108: 120-133, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34465426

RESUMO

Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere. The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site. The main species found in bioaerosols were assayed using high-throughput sequencing. The SourceTracker method was utilized to identify the sources of the bioaerosols present at the boundary of the landfill site. Furthermore, the health consequences of the exposure to bioaerosols were evaluated based on the average daily dose rates. Results showed that the concentrations of airborne bacteria in the operation area (OPA) and the leakage treatment area (LTA) were in the range of (4684 ± 477)-(10883 ± 1395) CFU/m3 and (3179 ± 453)-(9051 ± 738) CFU/m3, respectively. The average emission levels of fungal aerosols were 4026 CFU/m3 for OPA and 1295 CFU/m3 for LTA. The landfill site received the maximum bioaerosol load during summer and the minimum during winter. Approximately 41.39%- 86.24% of the airborne bacteria had a particle size of 1.1 to 4.7 µm, whereas 48.27%- 66.45% of the airborne fungi had a particle size of more than 4.7 µm. Bacillus sp., Brevibacillus sp., and Paenibacillus sp. were abundant in the bacterial population, whereas Penicillium sp. and Aspergillus sp. dominated the fungal population. Bioaerosols released from the working area and treatment of leachate were the two main sources that emerged in the surrounding air of the landfill site boundary. The exposure risks during summer and autumn were higher than those in spring and winter.


Assuntos
Microbiologia do Ar , Monitoramento Ambiental , Aerossóis/análise , Fungos , Medição de Risco , Estações do Ano , Instalações de Eliminação de Resíduos
14.
J Med Microbiol ; 70(9)2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34542396

RESUMO

To the best of our knowledge to date there are no scientific studies specifically investigating whether the SARS-CoV-2 virus is present in the air or on the various surfaces in the school environment. The aim of this study was to determine if SARS-CoV-2 is present on various high touch surfaces and in the air across the elementary, middle and high schools in the Chester County of Pennsylvania, USA. One hundred and fifty surface swab samples and 45 air samples were analysed for the presence of the virus. All the samples tested were negative for the presence of SARS-CoV-2. The results indicate that the spread of the virus through contact and through air in the school buildings across the USA is highly unlikely.


Assuntos
Microbiologia do Ar , COVID-19 , Pandemias/prevenção & controle , SARS-CoV-2/isolamento & purificação , Instituições Acadêmicas , COVID-19/transmissão , COVID-19/virologia , Humanos , Pennsylvania/epidemiologia
15.
PLoS One ; 16(9): e0258151, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34591919

RESUMO

BACKGROUND: Few studies have quantified aerosol concentrations of SARS-CoV-2 in hospitals and long-term care homes, and fewer still have examined samples for viability. This information is needed to clarify transmission risks beyond close contact. METHODS: We deployed particulate air samplers in rooms with COVID-19 positive patients in hospital ward and ICU rooms, rooms in long-term care homes experiencing outbreaks, and a correctional facility experiencing an outbreak. Samplers were placed between 2 and 3 meters from the patient. Aerosol (small liquid particles suspended in air) samples were collected onto gelatin filters by Ultrasonic Personal Air Samplers (UPAS) fitted with <2.5µm (micrometer) and <10 µm size-selective inlets operated for 16 hours (total 1.92m3), and with a Coriolis Biosampler over 10 minutes (total 1.5m3). Samples were assayed for viable SARS-CoV-2 virus and for the viral genome by multiplex PCR using the E and N protein target sequences. We validated the sampling methods by inoculating gelatin filters with viable vesicular stomatitis virus (VSV), and with three concentrations of viable SARS-CoV-2, operating personal samplers for 16hrs, and quantifying viable virus recovery by TCID50 assay. RESULTS: In total, 138 samples were collected from 99 rooms. RNA samples were positive in 9.1% (6/66) of samples obtained with the UPAS 2.5µm samplers, 13.5% (7/52) with the UPAS 10µm samplers, and 10.0% (2/20) samples obtained with the Coriolis samplers. Culturable virus was not recovered in any samples. Viral RNA was detected in 15.1% of the rooms sampled. There was no significant difference in viral RNA recovery between the different room locations or samplers. Method development experiments indicated minimal loss of SARS-CoV-2 viability via the personal air sampler operation.


Assuntos
Aerossóis/isolamento & purificação , Microbiologia do Ar , COVID-19/virologia , SARS-CoV-2/isolamento & purificação , Animais , COVID-19/epidemiologia , COVID-19/transmissão , Chlorocebus aethiops , Hospitais , Humanos , Assistência de Longa Duração , RNA Viral/isolamento & purificação , Células Vero
16.
JAMA Netw Open ; 4(9): e2126447, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34550382

RESUMO

Importance: Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in kindergarten through 12th grade settings. Objectives: To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for kindergarten through 12th grade in-person learning. Design, Setting, and Participants: This pilot quality improvement program engaged 3 schools in Omaha, Nebraska, for weekly saliva polymerase chain reaction testing of staff and students participating in in-person learning over a 5-week period from November 9 to December 11, 2020. Wastewater, air, and surface samples were collected weekly and tested for SARS-CoV-2 RNA to evaluate surrogacy for case detection and interrogate transmission risk of in-building activities. Main Outcomes and Measures: SARS-CoV-2 detection in saliva and environmental samples and risk factors for SARS-CoV-2 infection. Results: A total of 2885 supervised, self-collected saliva samples were tested from 458 asymptomatic staff members (mean [SD] age, 42.9 [12.4] years; 303 women [66.2%]; 25 Black or African American [5.5%], 83 Hispanic [18.1%], 312 White [68.1%], and 35 other or not provided [7.6%]) and 315 students (mean age, 14.2 [0.7] years; 151 female students [48%]; 20 Black or African American [6.3%], 201 Hispanic [63.8%], 75 White [23.8%], and 19 other race or not provided [6.0%]). A total of 46 cases of SARS-CoV-2 (22 students and 24 staff members) were detected, representing an increase in cumulative case detection rates from 1.2% (12 of 1000) to 7.0% (70 of 1000) among students and from 2.1% (21 of 1000) to 5.3% (53 of 1000) among staff compared with conventional reporting mechanisms during the pilot period. SARS-CoV-2 RNA was detected in wastewater samples from all pilot schools as well as in air samples collected from 2 choir rooms. Sequencing of 21 viral genomes in saliva specimens demonstrated minimal clustering associated with 1 school. Geographical analysis of SARS-CoV-2 cases reported district-wide demonstrated higher community risk in zip codes proximal to the pilot schools. Conclusions and Relevance: In this study of staff and students in 3 urban public schools in Omaha, Nebraska, weekly screening of asymptomatic staff and students by saliva polymerase chain reaction testing was associated with increased SARS-CoV-2 case detection, exceeding infection rates reported at the county level. Experiences differed among schools, and virus sequencing and geographical analyses suggested a dynamic interplay of school-based and community-derived transmission risk. Collectively, these findings provide insight into the performance and community value of test-based SARS-CoV-2 screening and surveillance strategies in the kindergarten through 12th grade educational setting.


Assuntos
Teste para COVID-19/métodos , COVID-19/epidemiologia , Monitoramento Ambiental , Programas de Rastreamento , Avaliação de Programas e Projetos de Saúde , Instituições Acadêmicas , População Urbana , Adolescente , Adulto , Microbiologia do Ar , COVID-19/virologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nebraska , Pandemias , Projetos Piloto , Reação em Cadeia da Polimerase , Medição de Risco , SARS-CoV-2 , Saliva , Professores Escolares , Estudantes , Águas Residuárias/virologia
17.
Environ Pollut ; 290: 118037, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34482243

RESUMO

Landfills, as well as other waste management facilities are well-known bioaerosols sources. These places may foment antibiotic-resistance in bacterial bioaerosol (A.R.B.) due to inadequate pharmaceutical waste disposal. This issue may foster the necessity of using last-generation antibiotics with extra costs in the health care system, and deaths. The aim of this study was to reveal the multi-antibiotic resistant bacterial bioaerosol emitted by a sanitary landfill and the surrounding area. We evaluated the influence of environmental conditions in the occurrence of A.R.B. and biological risk assessment. Antibiotic resistance found in the bacteria aerosols was compared with the AWaRE consumption classification. We used the BIOGAVAL method to assess the workers' occupational exposure to antibiotic-resistant bacterial bioaerosols in the landfill. This study confirmed the multi-antibiotic resistant in bacterial bioaerosol in a landfill and in the surrounding area. Obtained mean concentrations of bacterial bioaerosols, as well as antibiotic-resistant in bacterial bioaerosol (A.R.B.), were high, especially for fine particles that may be a threat for human health. Results suggest the possible risk of antibiotic-resistance interchange between pathogenic and non-pathogenic species in the landfill facilities, thus promoting antibiotic multi-resistance genes spreading into the environment.


Assuntos
Microbiologia do Ar , Antibacterianos , Aerossóis/análise , Bactérias , Monitoramento Ambiental , Humanos , Medição de Risco , Instalações de Eliminação de Resíduos
18.
Artigo em Inglês | MEDLINE | ID: mdl-34574831

RESUMO

Monitoring the indoor microclimate in old buildings of cultural heritage and significance is a practice of great importance because of the importance of their identity for local communities and national consciousness. Most aged heritage buildings, especially those made of wood, develop an indoor microclimate conducive to the development of microorganisms. This study aims to analyze one wooden church dating back to the 1710s in Romania from the microclimatic perspective, i.e., temperature and relative humidity and the fungal load of the air and surfaces. One further aim was to determine if the internal microclimate of the monument is favorable for the health of parishioners and visitors, as well as for the integrity of the church itself. The research methodology involved monitoring of the microclimate for a period of nine weeks (November 2020-January 2021) and evaluating the fungal load in indoor air as well as on the surfaces. The results show a very high contamination of air and surfaces (>2000 CFU/m3). In terms of fungal contamination, Aspergillus spp. (two different species), Alternaria spp., Cladosporium spp., Mucor spp., Penicillium spp. (two different species) and Trichopyton spp. were the genera of fungi identified in the indoor wooden church air and Aspergillus spp., Cladosporium spp., Penicillium spp. (two different species) and Botrytis spp. on the surfaces (church walls and iconostasis). The results obtained reveal that the internal microclimate not only imposes a potential risk factor for the parishioners and visitors, but also for the preservation of the wooden church as a historical monument, which is facing a crisis of biodeterioration of its artwork.


Assuntos
Poluição do Ar em Ambientes Fechados , Microbiologia do Ar , Poluição do Ar em Ambientes Fechados/análise , Alternaria , Monitoramento Ambiental , Fungos , Romênia
19.
Environ Monit Assess ; 193(10): 626, 2021 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-34482422

RESUMO

A simplified model has been devised to estimate the falling dynamics of severe acute respiratory syndrome corona-virus 2 (SARS-CoV-2)-laden droplets in an indoor environment. Our estimations were compared to existing literature data. The spread of SARS-CoV-2 is closely coupled to its falling dynamics as a function of respiratory droplet diameter (1 to 2000 µm) of an infected person and droplet evaporation. The falling time of SARS-CoV-2 with a respiratory droplet diameter of about 300 µm from a height of 1.7 m remained almost the same among the Newtonian lift equation, Stokes's law, and our simplified model derived from them so as to account for its evaporation. The evaporative demand peaked at midday which was ten times that at midnight. The evaporating droplets [Formula: see text] 6 µm lost their water content rapidly, making their lifetimes in the air shorter than their falling times. The droplets [Formula: see text] 6 µm were able to evaporate completely and remained in the air for about 5 min as droplet nuclei with SARS-CoV-2.


Assuntos
Aerossóis , Microbiologia do Ar , Monitoramento Ambiental , SARS-CoV-2 , Humanos , SARS-CoV-2/isolamento & purificação
20.
Artigo em Inglês | MEDLINE | ID: mdl-34444175

RESUMO

The present study was performed to quantitatively evaluate the effects of air purifiers on the spread of COVID-19 and to suggest guidelines for their safe use. To simulate respiratory droplet nuclei and nano-sized virus aggregates, deionized water containing 100 nm of polystyrene latex (PSL) particles was sprayed using a vibrating mesh nebulizer, and the changes in the particle number concentration were measured for various locations of the particle source and air purifier in a standard 30 m3 test chamber. The spread of the simulated respiratory droplet nuclei by the air purifier was not significant, but the nano-sized aggregates were significantly affected by the airflow generated by the air purifier. However, due to the removal of the airborne particles by the HEPA filter contained in the air purifier, continuous operation of the air purifier reduced the number concentration of both the simulated respiratory droplet nuclei and nano-sized aggregates in comparison to the experiment without operation of the air purifier. The effect of the airflow generated by the air purifier on the spread of simulated respiratory droplet nuclei and nano-sized aggregates was negligible when the distance between the air purifier and the nebulizer exceeded 1 m.


Assuntos
Filtros de Ar , SARS-CoV-2/isolamento & purificação , Vírus , Microbiologia do Ar , COVID-19/prevenção & controle , Humanos , Vírus/isolamento & purificação
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