ABSTRACT
Since the outbreak in December 2019, the SARS-CoV-2 pandemic virus has been a major public health problem in all countries of the world. The virus is transmitted by inhalation of respiratory droplets from the patient or asymptomatic carrier and is highly contagious. The clinical disease in children is similar to any acute respiratory infection with predominant upper respiratory symptoms, but occasionally can progress to pneumonia with acute respiratory distress syndrome and multiorgan failure. The disease is milder in children than in adults, with low mortality, and it appears that infants and young children have a somewhat more severe clinical course. Diagnosis is made by detecting the virus from respiratory samples (mainly nasopharyngeal and oropharyngeal swabs) using polymerase chain reaction. Treatment is usually symptomatic, and in severe and critical forms, the use of one of the antiviral drugs (lopinavir-ritonavir, remdesivir, hydroxychloroquine) may be consideredCopyright © 2020 Croatian Paediatric Society. All rights reserved.
ABSTRACT
On March 11, 2020, the World Health Organization (WHO) designated the new coronavirus COVID-19 to be epidemic. Adherence to infection control methods is strongly affected by an individual's knowledge, attitudes, and practices (KAP). The study aimed to evaluate medical students' understanding, and attitudes toward COVID-19 at the Kirkuk Medical College in Iraq. From October 16 to October 26, 2020, a cross-sectional online study was conducted, among a sample of students in Kirkuk Medical College, one of the Iraqi governorates. A total of 214 students were included in this research, and the age varied between 20-25 years. The questionnaire was divided into demographic data, knowledge, attitudes, and practices, modified from an online questionnaire regarding COVID-19 previously used. Descriptive statistics and t-tests were conducted. Among the study sample (n=214), age ranged between 20-25 years, 72.9% were females, and 86.9% resided in urban areas. The learning questionnaire's total accuracy rate was 96.3%. 98.1% of the students know that the virus is spreading by respiratory droplets from infected individuals, 30.4% have a good attitude towards COVID-19, and 100% have good practice dodging crowded places and practicing appropriate hand hygiene. The majority of students are knowledgeable of disease transference prevention and good practices. Female gender and urban residency play a positive role in knowledge and practice in respect to COVID-19 but not in what concerns the attitude. It is recommended to continue health education programs to correct the negative attitude among students, especially those who reside in rural areas.Copyright © 2023, Codon Publications. All rights reserved.
ABSTRACT
Background Available data on aerosol emisions in children and adolescents during spontaneous breathing are limited. Our aim was to gain insight into the role of children in the spread of SARS-CoV-2 and whether aerosol measurements in children can be used to help detect so-called superspreaders - infected individuals with extremely high numbers of exhaled aerosol particles. Methods In this prospective study, the aerosol concentration of SARS-CoV-2 PCR-positive and SARS-CoV-2 PCR-negative children and adolescents (2-17 years) was investigated. All subjects were asked about their current health status and medical history. The exhaled aerosol particle counts of PCR-negative and PCR-positive subjects were measured using the Resp-Aer-Meter (Palas GmbH, Karlsruhe, Germany) and compared using linear regresion. The study was registered in the German Register of Clinical Studies (DRKS), DRKS00028539. Results A total of 250 children and adolescents were included in the study, 105 of whom were SARS-CoV-2 positive and 145 of whom were SARS-CoV-2 negative. The median age acros both groups was nine years (IQR 7-11). A total of 124 (49.6%) participants were female, and 126 (50.4%) participants were male. A total of 81.9% of the SARS-CoV-2-positive group had symptoms of viral infection. The median particle count of all individuals was 79.55 p/l (IQR 44.55-141.15). There was a tendency for older children to exhale more particles (1-5 years: 79.54 p/l;6-11 years: 77.96 p/l;12-17 years: 98.63 p/l). SARS-CoV-2 PCR status was not a bivariate predictor (t=.82, p=.415) for the exhaled aerosol particle count;however, the SARS-CoV-2 status was shown to be a significant predictor in a multiple regresion model together with age, body mas index (BMI), covid vaccination, and past SARS-CoV-2 infection (t=.2.81 p=.005). Covid vaccination status was a highly significant predictor of exhaled aerosol particles (p <.001).Conclusion During SARS-CoV-2 infection, children and adolescents do not have elevated aerosol levels. In addition, no superspreaders were found. Children and adolescents are not the main driver of the SARS-CoV-2 pandemic. .
ABSTRACT
Coronavirus disease is a contagious respiratory ailment that has spread significantly around the world. Most cases of COVID-19 are spread from person to person by coming into contact with respiratory droplets that are released when an infected person coughs or sneezes. In this manuscript, we have highlighted the possible transmission of COVID-19 through food, water, air and paper. In the case of food, we have extensively covered the transmission of COVID-19 through meat, frozen foods, food packaging and food market along with the incidences worldwide. In the nextsection, we have highlighted the different components of air which are responsible for the transmission and also covered its relation with PM 2.5 incidence. The SARS-CoV-2 was isolated from sewage water/wastewater of various countries namely the United States, India, Australia, Netherlands and France signifying that wastewater can be a mode of virus transmission. The paper circulation by the infected COVID-19 patients can also be a virus conveyance route. It can be concluded that SARS-CoV-2 can therefore be transmitted indirectly through food via the workers involved in food packing or food marts.By following general safety precautions (wearing masks, using hand sanitisers, cleaning and disinfecting contact surfaces, and avoiding close contact), heating and using chemicals like ethanol (67-71%), sodium hypochlorite (0.1%) and hydrogen peroxide (0.5%) on environmental surfaces, along with vaccination, it is possible to reduce the spread of the SARS-CoV-2 virus.Copyright © 2023 The International Journal of Pharmaceutical Research and Allied Sciences (IJPRAS).
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The new coronavirus disease was declared by WHO as COVID-19 1 and the name of the virus causing this disease was defined as SARS-CoV-2 . The most common way of transmission of the virus is the close contact with infected people and respiratory droplets. Another common way of transmission is touching mouth, nose and eyes after touching surfaces contaminated with droplets shed by infected people. According to the results of the studies, the virus has a durability between 2-72 hours on different surfaces and items..Copyright © 2022, Universidade de Sao Paulo. Museu de Zoologia. All rights reserved.
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The proceedings contain 54 papers. The topics discussed include: cytokines in severe childhood asthma;transcriptional gene regulation of interleukin-6 in epithelial cells in viral-induced asthma exacerbation;assessment of the long-term safety and efficacy of dupilumab in children with asthma: LIBERTY ASTHMA EXCURSION;impulse oscillometry bronchodilator response in preschool children;pulmonary function in non-hospitalized adults and children after mild Covid-19;exhaled aerosols in PCR-confirmed SARS-CoV-2-infected children;early respiratory infectious diseases have an influence on the gut microbiome;comparison of three eradication treatment protocols for pseudomonas aeruginosa in children and adolescents with cystic fibrosis;neutrophilic airway inflammation in children with repaired esophageal atresia-tracheoesophageal fistula (EA/TEF);and multiplex immunofluorescence and multispectral imaging as a tool to evaluate host directed therapy.
ABSTRACT
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.
Subject(s)
COVID-19 , Respiration Disorders , Respiratory Tract Diseases , Humans , Respiratory Aerosols and DropletsABSTRACT
Airborne diseases, including COVID-19, are transmitted by respiratory droplets, which makes the study of the evolution of these droplets important to control the transmission. However, the evolution of the droplets is complex, being a multiphase, polydisperse, multicomponent system undergoing evaporation. To numerically investigate such multiphase flows, there are mainly two approaches. One is the Eulerian–Lagrangian (E–L) approach, which is widely used due to its ability to trace the dispersion and evaporation of individual droplets. However, this approach generally has high costs and difficulty in post-processing. The other one is the Eulerian–Eulerian (E–E) approach, which, though having lower costs, is less adopted because of its failure to treat the features of polydispersity and evaporation. In order to take advantage of the low-costs of E–E approach, the population balance equation (PBE) is combined with the E–E approach to trace the polydisperse evaporating droplets. Two PBE solving methods, sectional method (SM) and quadrature based moment method (QBMM), are used and compared. The codes are developed based on the OpenFOAM library and their abilities to predict size changes of evaporating droplets, evolution of expelled airflow front, and aerosols concentration are assessed by using the experimental and numerical results in literature. Good agreements with the reported results are found, indicating the reliability of the CFD-PBE approaches. The SM and QBMM are finally applied in the transport of cough droplets in a 3D chamber. The suspending trends of small droplets and the falling trends of the large droplets are obtained by both methods. The droplets are found to be able to travel a distance longer than 2 m, which is valuable for the guidelines of social distancing. Additionally, the advantages and disadvantages of SM and QBMM are discussed.
ABSTRACT
The outbreak of coronavirus disease 2019 (COVID-19) was first reported in Wuhan, Chi-na, and soon the infection turned into a pandemic. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the spread of COVID-19 infection. The World Health Organization (WHO) confirmed 4.20% of total deaths globally (March 21, 2020). Within four months (July 21, 2020), the rate of confirmed total deaths was recorded up to 4.17% globally. In India, 909 confirmed cases and 19 deaths were reported by Health and Family Welfare, Government of India, on March 28, 2020. Over a period of 123 days in India, 1638870 confirmed cases and 35684 deaths were reported. COVID-19 can potentially spread from person to person through direct contact or respiratory droplets from coughing and sneezing. The most common symptoms are fever, dry cough, difficulty in breathing, and fatigue. A pregnant mother with COVID-19 has fewer chances of trans-ferring this infection to her newborn baby. Children are less affected than adults from this virus. A specific antiviral drug or vaccine has not been developed to cure the disease to date. Drugs including chloroquine, hydroxychloroquine, lopinavir, ritonavir, nafamostat, nitazoxanide, and remde-sivir, have been observed to be effective for treating COVID-19. Many vaccine candidates are under investigation in pre-clinical and clinical studies. In this review, we highlight the epidemiology, signs and symptoms, pathogenesis, and mode of transmission of the infection caused by COVID-19, and its effects on a pregnant mother and newborn, and children. We also highlight the preventive measures and drugs that are effective for treating COVID-19.Copyright © 2021 Bentham Science Publishers.
ABSTRACT
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.
ABSTRACT
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.
Subject(s)
COVID-19 , Cough , Humans , Pandemics , Physical Phenomena , SneezingABSTRACT
To quantify the risk of the transmission of respiratory infections in indoor environments, we systematically assessed exposure to talking- and breathing-generated respiratory droplets in a generic indoor environment using computational fluid dynamic (CFD) simulations. The flow field in the indoor environment was obtained with SST k-ω model and Lagrangian method was used to predict droplet trajectories, where droplet evaporation was considered. Droplets can be categorized into small droplets (initial size ≤30 μm or ≤10 μm as droplet nuclei), medium droplets (30–80 μm) and large droplets (>100 μm) according to the exposure characteristics. Droplets up to 100 μm, particular the small ones, can contribute to both short-range and long-range airborne routes. For the face-to-face talking scenario, the intake fraction and deposition fractions of droplets on the face and facial mucosa of the susceptible were up to 4.96%, 2.14%, and 0.12%, respectively, indicating inhalation is the dominant route. The exposure risk from a talking infector decreases monotonically with the interpersonal distance, while that of nasal-breathing generated droplets maintains a relatively stable level within 1.0 m. Keeping an angle of 15° or above with the expiratory flow is efficient to reduce intake fractions to <0.37% for small droplets. Adjusting the orientation from face-to-face to face-to-back can reduce exposure to small droplets by approximately 88.0% during talking and 66.2% during breathing. A higher ventilation rate can reduce the risk of exposure to small droplets but may increase the risk of transmission via medium droplets by enhancing their evaporation rate. This study would serve as a fundamental research for epidemiologist, healthcare workers and the public in the purpose of infection control. © 2023 Elsevier Ltd
ABSTRACT
Airborne transmission of respiratory viruses consists of three sequential steps: (1) release of respiratory fluids in the form of droplets from the nose and mouth of an infected person, (2) transport of the droplets through air, and (3) entry of the droplets into the nose and mouth of an uninfected individual. Talking, coughing, and sneezing emit droplets across a spectrum of sizes. The water in exhaled droplets begins to evaporate in air and, as a result, the droplets are reduced in size shortly after being emitted. Face masks are effective for capturing droplets just released from the nose and mouth. Studies indicate that more than 50% of community transmission of SARS-CoV-2 is from asymptomatic and pre-symptomatic cases. Use of face masks by the public can effectively reduce the chance of infected individuals unknowingly spreading the virus. In addition to being an effective device for source control, face masks can protect the wearers from inhaling virus-laden droplets. Cloth masks and disposable masks provide reasonable protection for the public, while surgical masks and N95 respirators give higher levels of protection as needed in healthcare settings. Made with varied materials, these masks have different structural characteristics. The collection efficiency of a face mask depends on droplet size, face velocity, and the structural characteristics of the mask. For a given mask, capturing droplets is more effective during exhalation than during inhalation. Pressure drop across the mask should be taken into consideration when selecting a face mask. The best face mask is the one that gives the highest collection efficiency with the least pressure drop. For an effective protection, a mask should fit the face properly. While face masks have proven adequate in reducing airborne transmission of SARS-CoV-2 infections, continuous improvement is needed to better prepare for future respiratory viral threats. © The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.
ABSTRACT
COVID-19 is highly contagious and transmission dynamics of COVID-19 are not yet fully elucidated. It is known that the ill person begins to become contagious before the symptoms of the disease begin. Also asymptomatic person who are infected but does not have symptoms and signs, can infect other individuals. The only way for health workers to protect themselves from COVID-19 is proper use of personal protective equipment and to ensure hand hygiene. COVID-19 is transmitted through close contact and large respiratory droplets and not transmitted by airborne. The surgical mask prevents the passage of respiratory droplets. However, during the aerosol producing procedures performed on the patient, small particles containing infectious particles are scattered to air in high amounts. Healthcare workers are more likely become infected during these procedures. It is recommended to wear respirator during these procedures. Use of masks or respirators must be in conjunction with other recommended PPE and appropriate hand hygiene.
ABSTRACT
Airborne transmission of respiratory viruses consists of three sequential steps: (1) release of respiratory fluids in the form of droplets from the nose and mouth of an infected person, (2) transport of the droplets through air, and (3) entry of the droplets into the nose and mouth of an uninfected individual. Talking, coughing, and sneezing emit droplets across a spectrum of sizes. The water in exhaled droplets begins to evaporate in air and, as a result, the droplets are reduced in size shortly after being emitted. Face masks are effective for capturing droplets just released from the nose and mouth. Studies indicate that more than 50% of community transmission of SARS-CoV-2 is from asymptomatic and pre-symptomatic cases. Use of face masks by the public can effectively reduce the chance of infected individuals unknowingly spreading the virus. In addition to being an effective device for source control, face masks can protect the wearers from inhaling virus-laden droplets. Cloth masks and disposable masks provide reasonable protection for the public, while surgical masks and N95 respirators give higher levels of protection as needed in healthcare settings. Made with varied materials, these masks have different structural characteristics. The collection efficiency of a face mask depends on droplet size, face velocity, and the structural characteristics of the mask. For a given mask, capturing droplets is more effective during exhalation than during inhalation. Pressure drop across the mask should be taken into consideration when selecting a face mask. The best face mask is the one that gives the highest collection efficiency with the least pressure drop. For an effective protection, a mask should fit the face properly. While face masks have proven adequate in reducing airborne transmission of SARS-CoV-2 infections, continuous improvement is needed to better prepare for future respiratory viral threats. © The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.
ABSTRACT
To quantify the risk of the transmission of respiratory infections in indoor environments, we systematically assessed exposure to talking- and breathing-generated respiratory droplets in a generic indoor environment using computational fluid dynamic (CFD) simulations. The flow field in the indoor environment was obtained with SST k-ω model and Lagrangian method was used to predict droplet trajectories, where droplet evaporation was considered. Droplets can be categorized into small droplets (initial size ≤30 μm or ≤10 μm as droplet nuclei), medium droplets (30–80 μm) and large droplets (>100 μm) according to the exposure characteristics. Droplets up to 100 μm, particular the small ones, can contribute to both short-range and long-range airborne routes. For the face-to-face talking scenario, the intake fraction and deposition fractions of droplets on the face and facial mucosa of the susceptible were up to 4.96%, 2.14%, and 0.12%, respectively, indicating inhalation is the dominant route. The exposure risk from a talking infector decreases monotonically with the interpersonal distance, while that of nasal-breathing generated droplets maintains a relatively stable level within 1.0 m. Keeping an angle of 15° or above with the expiratory flow is efficient to reduce intake fractions to <0.37% for small droplets. Adjusting the orientation from face-to-face to face-to-back can reduce exposure to small droplets by approximately 88.0% during talking and 66.2% during breathing. A higher ventilation rate can reduce the risk of exposure to small droplets but may increase the risk of transmission via medium droplets by enhancing their evaporation rate. This study would serve as a fundamental research for epidemiologist, healthcare workers and the public in the purpose of infection control.
ABSTRACT
Purpose : COVID-19 pandemic has become a major global public health challenge. The ophthalmology office setting involves close encounters between the patient and the health care workers increasing risk of viral transmission. Use of PPE decreases risk of person-to-person viral transmission. The purpose of the study was to evaluate breath-induced air currents in subjects without a facemask, with a procedure mask, with an improvised face, and in the setting of slit-lamp examination. Methods : Breath-induced air currents were studied in healthy volunteers utilizing a vape pod system and videography during gentle and heavy breathing simulation. Video frames at 2 seconds after the initiation of expiration were captured and analyzed. Results : A total of 210 recordings were made for 7 settings. Without a face mask, the aerosol moved forwards and spread vertically and horizontally reaching a mean distance of 23.1 inches for gentle, and 36.1 inches for heavy breathing at 2 seconds (P< 0.001). Using PPE the airflow patterns included: a) procedure mask- forward 0 cases, upward 19 (63%) cases, side 28 (93%) cases, downward 22 (73%) cases, and backward 22 (73%) cases. Adding a tape at the upper border of the mask eliminated upward flow in all cases. b) Improvised face mask- forward 0 cases, upward 0 cases, side 30 (100%) cases, downward 30 (100%) cases, and backward 17 (57%) cases. In 14 (47%) cases trace of aerosol was detected adjacent to the front surface of the mask. Adding a second layer eliminated the trace of aerosol in all cases. In the setting of simulated slit-lamp examination without the breath shield, the aerosol reached the chin rest in 9 (60%) cases during gentle breathing and in all cases during heavy breathing. The breath shield was effective in blocking forward airflow in all cases. Conclusions : Use of a procedure mask by patients, while effective in blocking forward breath-induced airflow, redirects the flow upwards, potentially increasing the risk of contamination during an office procedure. An improvised facemask alters breath-induced air currents favorably and partially absorbs respiratory droplets.
ABSTRACT
Public health and societal efforts can avoid the 2019 Corona pandemic (COVID-19). Ethiopia has adopted health and social measures. COVID-19 social distance and health prevention research. SARS-CoV-2 produces COVID-19. The global vaccine effort must understand how the virus spreads to end the pandemic. SARS-CoV-2 spreads by respiratory droplets and aerosols, according to new studies. Temperature, humidity, precipitation, air currents, pH, and radiation affect transmission. Hand washing and masks are also helpful public health measures. Non-pharmaceutical remedies need more research. Body-invading eye bacteria exist. There's no indication that COVID-19 exposure causes the disorder's ocular symptoms. Tears and conjunctiva contained SARS-CoV-2. Ocular symptoms may be the first or only sign of infection. Hand cleanliness, social isolation, and hospital SOPs can limit illness spread. Eye lubricants and spectacles can prevent eye infections.
ABSTRACT
I will discuss our lab's efforts, together with collaborators, to use computational microscopy to understand the SARS-CoV-2 virus in atomic detail, with the goals to better understand molecular recognition of the virus and host cell receptors, antibody binding and design, and the search for novel therapeutics. I will focus on our studies of the spike protein, its glycan shield, its interactions with the human ACE2 receptor, our ACM Gordon Bell Special Prize winning efforts to model the SARS-CoV-2 virion, and escape variants. I will also discuss our efforts to completely revise current models of airborne transmission of respiratory viruses by providing never-before-seen atomic level views of the SARSCoV-2 virus within a respiratory aerosol.
ABSTRACT
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.