Academic literature on the topic 'Droplet infections'
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Journal articles on the topic "Droplet infections"
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Mangini, Ed, Sorana Segal-Maurer, Janice Burns, Annette Avicolli, Carl Urban, Noriel Mariano, Louise Grenner, Carl Rosenberg, and James J. Rahal. "Impact of Contact and Droplet Precautions on the Incidence of Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Infection." Infection Control & Hospital Epidemiology 28, no. 11 (November 2007): 1261–66. http://dx.doi.org/10.1086/521658.
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Objective.To evaluate the efficacy of contact and droplet precautions in reducing the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections.Design.Before-after study.Setting.A 439-bed, university-affiliated community hospital.Methods.To identify inpatients infected or colonized with MRSA, we conducted surveillance of S. aureus isolates recovered from clinical culture and processed by the hospital's clinical microbiology laboratory. We then reviewed patient records for all individuals from whom MRSA was recovered. The rates of hospital-acquired MRSA infection were tabulated for each area where patients received nursing care. After a baseline period, contact and droplet precautions were implemented in all intensive care units (ICUs). Reductions in the incidence of hospital-acquired MRSA infection in ICUs led to the implementation of contact precautions in non-ICU patient care areas (hereafter, “non-ICU areas”), as well. Droplet precautions were discontinued. An analysis comparing the rates of hospital-acquired MRSA infection during different intervention periods was performed.Results.The combined baseline rate of hospital-acquired MRSA infection was 10.0 infections per 1,000 patient-days in the medical ICU (MICU) and surgical ICU (SICU) and 0.7 infections per 1,000 patient-days in other ICUs. Following the implementation of contact and droplet precautions, combined rates of hospital-acquired MRSA infection in the MICU and SICU decreased to 4.3 infections per 1,000 patient-days (95% confidence interval [CI], 0.17-0.97; P = .03). There was no significant change in hospital-acquired MRSA infection rates in other ICUs. After the discontinuation of droplet precautions, the combined rate in the MICU and SICU decreased further to 2.5 infections per 1,000 patient-days. This finding was not significant (P = .43). In the non-ICU areas that had a high incidence of hospital-acquired MRSA infection, the rate prior to implementation of contact precautions was 1.3 infections per 1,000 patient-days. After the implementation of contact precautions, the rate in these areas decreased to 0.9 infections per 1,000 patient-days (95% CI, 0.47-0.94; P = .02).Conclusion.The implementation of contact precautions significantly decreased the rate of hospital-acquired MRSA infection, and discontinuation of droplet precautions in the ICUs led to a further reduction. Additional studies evaluating specific infection control strategies are needed.
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Ling, Wei, Maho Ichikawa, Kaho Hashimoto, Masayuki Ogata, Hitomi Tsutsumi, Shoichi Morimoto, Shin-ichi Tanabe, and Satoshi Hori. "Evaluation of Short-Distance Airborne Infection Risk Using a Cough Generator." E3S Web of Conferences 111 (2019): 02028. http://dx.doi.org/10.1051/e3sconf/201911102028.
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Short-distance airborne infections are often thought to occur by large droplets or direct contact. Recent studies have investigated the phenomenon of short-range airborne infection. In this study, the effect of relative humidity and short-distance exposure to cough droplet nuclei were evaluated. The evaluation model for infection risk was designed based on experimental data and previous studies and included sampling efficiency and virus survival rate. As observed in the comparison between short-range exposure and long-range exposure, the short-range exposure to the droplet nuclei by one cough was equivalent to a long-range exposure of several seconds to, depending on the number of ventilations, even for a momentary high-concentration exposure. This suggests the possibility of an infection risk corresponding to the receiving condition. Since short-range exposure and long-range exposure have different factors affecting the risk of infection, it is suggested that effective infection control should be selected for each condition. The risk of infection due to long-range exposure is considered to be sufficiently reduced to that of a single cough if the building meets the necessary number of ventilations. It was suggested that the influence of relative humidity on infection risks is smaller than other factors such as ventilation.
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Oye, Tosin T., Naren Gupta, Keng Goh, and Toyosi K. Oye. "Air-Conditioning and the Transmission of COVID-19 in Indoor Environment." Environmental Management and Sustainable Development 10, no. 3 (May 22, 2021): 1. http://dx.doi.org/10.5296/emsd.v10i3.18461.
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Substandard ventilation in restricted air-conditioning indoor places is allied with upsurge in the respiratory infections’ transmission. There have been several COVID-19 spread occurrences connected with indoor environment, together with a few from pre-symptomatic situations. Ventilation role in averting coronavirus transmission is not precise (i.e., through inhibiting transmission of an infectious dose to susceptible individuals or preventing the spreading of contagious particles to lessen the risk of transmission). SARS-CoV-2 is believed to be mainly spread through significant respiratory droplets, nevertheless, a growing amount of epidemic information associate aerosol role in the epidemics of coronavirus. Aerosols comprise of droplet nuclei and little droplets which stay in the air for longer than significant droplets. Recent studies show that coronavirus particles can stay transmissible on numerous substances, including aerosols within the indoor environments, as well as the contagion period contingent on humidity and temperature. Thus far, COVID-19 transmission via air-conditioning systems is unclear, but it is considered possible.
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Monson, Ebony A., Donna R. Whelan, and Karla J. Helbig. "Lipid Droplet Motility Increases Following Viral Immune Stimulation." International Journal of Molecular Sciences 22, no. 9 (April 23, 2021): 4418. http://dx.doi.org/10.3390/ijms22094418.
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Lipid droplets (LDs) have traditionally been thought of as solely lipid storage compartments for cells; however, in the last decade, they have emerged as critical organelles in health and disease. LDs are highly dynamic within cells, and their movement is critical in organelle–organelle interactions. Their dynamics are known to change during cellular stress or nutrient deprivation; however, their movement during pathogen infections, especially at very early timepoints, is under-researched. This study aimed to track LD dynamics in vitro, in an astrocytic model of infection. Cells were either stimulated with a dsRNA viral mimic, poly I:C, or infected with the RNA virus, Zika virus. Individual LDs within infected cells were analysed to determine displacement and speed, and average LD characteristics for multiple individual cells calculated. Both LD displacement and mean speed were significantly enhanced in stimulated cells over a time course of infection with an increase seen as early as 2 h post-infection. With the emerging role for LDs during innate host responses, understanding their dynamics is critical to elucidate how these organelles influence the outcome of viral infection.
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Abdelnaby, Asmaa, Laila Mahmoud Kamel, Jylan Elguindy, Reham Yousri Elamir, and Eman Elfar. "Exploring Safety Aspects in Dental School Clinics Including Droplet Infection Prevention." Open Access Macedonian Journal of Medical Sciences 8, E (September 2, 2020): 509–15. http://dx.doi.org/10.3889/oamjms.2020.4941.
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BACKGROUND: Health-care safety focuses on improving patient’s and worker’s safety in a safe working clinics’ environment and prevent infection transmission including droplet infections as seasonal influenza and novel coronavirus (COVID-19). Dental health-care personnel (DHCP) are the target of safety measures and are themselves responsible for elimination of preventable harm. Dental schools are expected to demonstrate the model for quality safe care.
AIM: This study aims to achieve high-quality safe dental care at dental clinics, Faculty of Dentistry, Cairo University.
METHODS: A cross-sectional survey study was conducted at two Dental Outpatient Clinics, Cairo University. Disk review of policies, observation checklists for practices and awareness questionnaires of DHCP were used.
RESULTS: DHCP showed good awareness for most of infection control (IC) and X-ray safety items. However, there are no policies or procedures to control droplet infections in the clinics. The clinics were closed in the current COVID-19 pandemic. There were poor patient safety practices, hand hygiene compliance, and personal protective equipment (PPE) use except for protecting clothes and disposable gloves. Students showed better compliance for patient safety guidelines. Other safety policies were poorly communicated.
CONCLUSION: There should be preparedness plan to deal with any droplet infection outbreak, epidemic or pandemic as COVID-19 in all dental settings. There is a need to initiate dental safety unit in dental schools to implement, communicate, train, and supervise all dental safety practices including infection control.
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Kähler, Christian J., and Rainer Hain. "Fundamental protective mechanisms of face masks against droplet infections." Journal of Aerosol Science 148 (October 2020): 105617. http://dx.doi.org/10.1016/j.jaerosci.2020.105617.
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Alsamarai, Abdulghani M., and Hala M. Hassan. "Maternal Infections Associated with Bad Obstetric Outcome: Toxoplasmosis and Rubella." International Journal of Medical Sciences 1, no. 3 (August 1, 2018): 5–11. http://dx.doi.org/10.32441/ijms.v1i3.97.
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Toxoplasmosis is caused by infection with the obligated intracellular protozoan parasite Toxoplasma gondii. It is one of the most prevalent chronic infections affecting one third of the world's human population. The prevalence of T. gondii infection varies among different geographical regions. The infection is characterized by non-specific signs with the consequent formation of cysts that may stay in latent form in many organs. Primary infection is usually subclinical but in some patient's cervical lymphoadenopathy or ocular disease can be present. Rubella is a mild disease caused by a togavirus. There may be a mild prodromal illness involving a low-grade fever, malaise, coryza and mild conjunctivitis. Lymphadenopathy involving post-auricular and sub-occipital glands may lead to rash. The rash is usually transitory, erythematous and mostly seen behind the ears and on the face and neck. Clinical diagnosis is unreliable as the rash may be fleeting and is not specific to rubella. Rubella is spread by droplet transmission. The incubation period is 14 to 21 days, with the majority of individuals developing a rash 14 to 17 days after exposure. Individuals with rubella are infectious from one week before symptoms appear to four days after the onset of the rash. Complications include thrombocytopaenia (the rate may be as high as one in 3000 infections) and post-infectious encephalitis (one in 6000 cases).
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Hertzberg, Vicki Stover, Howard Weiss, Lisa Elon, Wenpei Si, and Sharon L. Norris. "Behaviors, movements, and transmission of droplet-mediated respiratory diseases during transcontinental airline flights." Proceedings of the National Academy of Sciences 115, no. 14 (March 19, 2018): 3623–27. http://dx.doi.org/10.1073/pnas.1711611115.
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With over 3 billion airline passengers annually, the inflight transmission of infectious diseases is an important global health concern. Over a dozen cases of inflight transmission of serious infections have been documented, and air travel can serve as a conduit for the rapid spread of newly emerging infections and pandemics. Despite sensational media stories and anecdotes, the risks of transmission of respiratory viruses in an airplane cabin are unknown. Movements of passengers and crew may facilitate disease transmission. On 10 transcontinental US flights, we chronicled behaviors and movements of individuals in the economy cabin on single-aisle aircraft. We simulated transmission during flight based on these data. Our results indicate there is low probability of direct transmission to passengers not seated in close proximity to an infectious passenger. This data-driven, dynamic network transmission model of droplet-mediated respiratory disease is unique. To measure the true pathogen burden, our team collected 229 environmental samples during the flights. Although eight flights were during Influenza season, all qPCR assays for 18 common respiratory viruses were negative.
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Dombrovsky, Leonid, Alexander Fedorets, Vladimir Levashov, Alexei Kryukov, Edward Bormashenko, and Michael Nosonovsky. "Modeling Evaporation of Water Droplets as Applied to Survival of Airborne Viruses." Atmosphere 11, no. 9 (September 10, 2020): 965. http://dx.doi.org/10.3390/atmos11090965.
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Many viruses, such as coronaviruses, tend to spread airborne inside water microdroplets. Evaporation of the microdroplets may result in a reduction of their contagiousness. However, the evaporation of small droplets is a complex process involving mass and heat transfer, diffusion, convection and solar radiation absorption. Virological studies indicate that airborne virus survival is very sensitive to air humidity and temperature. We employ a model of droplet evaporation with the account for the Knudsen layer. This model suggests that evaporation is sensitive to both temperature and the relative humidity (RH) of the ambient air. We also discuss various mechanisms such as the effect of solar irradiation, the dynamic relaxation of moving droplets in ambient air and the gravitational sedimentation of the droplets. The maximum estimate for the spectral radiative flux in the case of cloudless sky showed that the radiation contribution to evaporation of single water droplets is insignificant. We conclude that at small and even at moderately high levels of RH, microdroplets evaporate within dozens of seconds with the convective heat flux from the air being the dominant mechanism in every case. The numerical results obtained in the paper are in good qualitative agreement with both the published laboratory experiments and seasonal nature of many viral infections. Sophisticated experimental techniques may be needed for in situ observation of interaction of viruses with organic particles and living cells within microdroplets. The novel controlled droplet cluster technology is suggested as a promising candidate for such experimental methodology.
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Ostovar, Gholamabbas Amin, Nina Kohn, Karl O. A. Yu, Susan Nullet, and Lorry G. Rubin. "Nosocomial Influenza in a Pediatric Hospital: Comparison of Rates of Seasonal and Pandemic 2009 Influenza A/H1N1 Infection." Infection Control & Hospital Epidemiology 33, no. 03 (March 2012): 292–94. http://dx.doi.org/10.1017/s0195941700030861.
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The rates of nosocomial seasonal (January 2008 to March 2009) and 2009 A/H1N1 (April 2009 to December 2010) influenza infections in a children's hospital were compared. Droplet precautions were used. The rates were similar during both periods, suggesting that use of droplet precautions did not result in a higher rate of influenza A/H1N1 infection.Infect Control Hosp Epidemiol2012;33(3):292-294
Dissertations / Theses on the topic "Droplet infections"
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Le, Gal Solène. "Réservoir humain et pneumocystose nosocomiale : approche des concepts par la détection, l'identification et l'étude de la diversité de Pneumocystis jirovecii." Thesis, Brest, 2013. http://www.theses.fr/2013BRES0009.
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Le genre Pneumocystis désigne un groupe de champignons opportunistes présentant une étroite spécificité d'hôte. Il détermine lors d'immunodépression sévère une infection pulmonaire grave, la pneumonie à Pneumocystis (PPC). La transmission de Pneumocystis par voie aérienne d'un hôte développant une PPC à un hôte susceptible a été démontrée à l'aide des modèles murins. Les travaux menés chez la souris ont montré également que des sujets immunocompétents colonisés par Pneumocystis murina peuvent transmettre le champignon à des souris immunodéprimées qui développeront une PPC ultérieurement. Les individus colonisés par Pneumocystis sp., ainsi que ceux développant une PPC, participeraient au réservoir du champignon. La survenue de cas groupés de PPC en milieu hospitalier est en faveur de la transmission interindividuelle de Pneumocystis jirovecii (P.jirovecii) chez l’homme. La détection de l'ADN de P.jirovecii dans l'air exhalé par les patients développant une PPC suggère que cette transmission se fait par voie aérienne. La caractérisation des populations infectées par P.jirovecii et la caractérisation génotypique du champignon au sein de son réservoir humain constituent la base de ce travail de recherche. Nous avons montré que la prévalence de la colonisation par P.jirovecii est faible chez les patients atteints de mucoviscidose et suivis dans notre CHU. La participation de ces patients au réservoir de P.jirovecii à Brest serait donc marginale. Cette faible prévalence pourrait être le reflet d'une faible circulation du champignon dans les communautés humaines dans notre région. Nous avons évalué le dosage du ß-1,3-D glucane sérique pour dépister les populations infectées. Ce dosage couplé à la détection de P.jirovecii dans les prélèvements respiratoires par la microscopie et la PCR, permet de différencier les patients développant une PPC et les patients présentant une colonisation pulmonaire par P.jirovecii. De plus, les premières données sur le ß-1,3-D glucane au cours de la primo-infection chez le nourrisson ont été obtenues.En termes de caractérisation de P.jirovecii dans notre région, l'analyse du locus dihydropteroate synthase (DHPS) a montré que: i) le lieu habituel de résidence plutôt que le lieu de diagnostic de l’infection à P.jirovecii serait un facteur prédictif d’infection par un mutant, ii) P.jirovecii pourrait circuler en France d’une région à une autre via des voyageurs infectés, iii) la prévalence de mutants potentiellement résistants chez les patients vivant effectivement à Brest était de 0%. L'analyse des séquences des "internal transcribed spacers" (ITS) 1 et 2 de P. jirovecii conforte l'hypothèse que les patients développant une PPC et les patients colonisés sont infectés par des populations fongiques présentant des caractéristiques identiques. Tous les patients, quelle que soit la présentation clinique de leur infection, constitueraient un réservoir unique et commun de P.jirovecii. Les travaux de génotypage ont constitué l'étape préalable nécessaire à l'analyse de cas groupés d'infections à P.jirovecii survenus chez des patients transplantés rénaux au CHU de Brest. Nous avons apporté des données originales sur le rôle des patients colonisés en tant que source potentielle de P. jirovecii dans un contexte d'acquisition et de transmission nosocomiales du champignon. Par ailleurs, la concordance partielle ou complète des génotypes ITS et DHPS dans les couples "prélèvements d'air–LBA" réalisés chez des patients développant une PPC est compatible avec l’exhalation du champignon et sa diffusion aérienne dans l’environnement hospitalier. Ces données apportent des arguments pour l'application de mesures de prévention des infections nosocomiales à P. jirovecii. Les précautions "gouttelettes" recommandées par la Société Française d'Hygiène Hospitalière devraient être appliquées a minima aux patients développant une PPC. Nous proposons leur extension aux patients colonisés par le champignonThe genus Pneumocystis represents a group of opportunistic fungi that show strong host specificity. It is the cause of severe pneumonia (Pneumocystis Pneumonia [PCP]) in immunocompromised subjects. Pneumocystis transmission from a host with PCP to another susceptible host via the airborne route has been demonstrated in rodent models. Moreover, it has been established that Pneumocystis murina can be transmitted from immunocompetent mice, transiently colonized by the fungus, to immunocompromised susceptible mice that subsequently develop PCP. Colonized subjects and those developing PCP may be part of the fungus reservoir. Reports of PCP case cluster in hospital strongly suggest that Pneumocystis jirovecii (P.jirovecii) transmission in humans may also occur. P.jirovecii DNA detection in the air surrounding PCP patients is consistent with the transmission of P.jirovecii via the airborne route.Our goals were to characterize human populations infected with P.jirovecii and to characterize P.jirovecii within its human reservoir. We showed that P.jirovecii was rarely involved in pulmonary colonization in patients with cystic fibrosis monitored in the Brest Hospital. Thus this patient population was not part of the human reservoir of the fungus in our region (Brittany, Western France). This low prevalence of colonization may reflect a low level of P.jirovecii circulation within human communities in Brittany. In order to improve the identification of patients infected with P.jirovecii, we evaluated ß-1,3-D glucan detection in serum samples. We showed that serum ß-1,3-D glucan levels combined with P.jirovecii detection in pulmonary samples using microscopic examination and a PCR assay make it possible to distinguish between PCP and pulmonary colonization. Moreover the first data on ß-1,3-D glucan levels during primary infection were obtained.In order to characterize P.jirovecii in our region, we performed the typing of P.jirovecii isolates from infected patients monitored at Brest hospital, using the dihydropteroate synthase (DHPS) and the internal transcribed spacer (ITS) 1 and 2 locus analysis. DHPS typing showed that i) the usual city of patient residence rather that the city in which the diagnosis of P.jirovecii infection has been made is a predictor of mutants, ii) mutants can be imported from one region to another through infected visitors, iii) the prevalence of mutants potentially resistant to sulfonamides was 0% in patients who effectively lived in the Brest geographic area. Results of ITS analysis in PCP patients and colonized patients are consistent with the hypothesis that these 2 patient groups are infected with similar P.jirovecii populations. All infected patients, whatever their clinical presentation, may be part of a common and unique reservoir of the fungus. We investigated an outbreak of P.jirovecii infections in 18 renal transplant recipients using the same typing method combined with patient encounter analysis. The results provided evidence of the role of colonized patients as potential sources of P.jirovecii. The same typing method was applied to pairs of pulmonary samples and room air samples of PCP patients. Full or partial matches of P.jirovecii types in pulmonary and air sample pairs were observed. These results are consistent with P.jirovecii exhalation by PCP patients in their close environment. These data support arguments for applying droplet precautions, at least to PCP patients, to prevent P.jirovecii transmission, as recommended by the "Société française d'hygiène hospitalière". We suggest extending droplet precautions to colonized patients to achieve the prevention of P.jirovecii nosocomial infections
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Xie, Xiaojian. "Evaporation and movement of respiratory droplets in indoor environments." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40987802.
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Liu, Li, and 刘荔. "Expiratory droplet exposure between individuals in a ventilated room." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47246248.
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Interpersonal transport of expiratory droplets and droplet nuclei constitutes a prerequisite for the transmission of pathogens as well as the transmission of respiratory diseases. This study modeled the physical process of interpersonal transport of droplets and droplet nuclei in a ventilated room. The impacts of a number of parameters in three length scales and three corresponding physical processes were analyzed, including dispersion and evaporation of droplets/droplet nuclei at 1 to 100 μm, human exhalation flows and body plumes at 0.1 to 1 m, and the indoor environment at 1 to 10 m.
The strong hygroscopicity of the solutes in the droplet is capable of keeping the droplet with an equilibrium size in humid air, larger than that of a dried particle. Mathematical models were developed to predict the droplet nucleus size in both dry air and humid air, by simplifying the composition of one expiratory droplet to NaCl solution and suspended spherical particles. For a droplet with an initial diameter of 100 μm, initial NaCl concentration of 0.9%, and initial solids ratio of 1.8%, the droplet nucleus size was estimated to be 42 μm in an ambient relative humidity of 90% (25°C), which is 30% larger than it was in a relative humidity of 30% (25°C). A numerical model was also developed to predict droplet evaporation and dispersion in a constant turbulent buoyant jet. Droplets with initial sizes larger than 80 μm were predicted to deposit on the floor at a distance of ~1.25 m (~1.7 m for 60 μm) away from the mouth, while droplets with initial sizes less than 40 μm travelled to the end of the jet.
A series of experiments was conducted to assess the characteristics of human exhalation airflows and thermal plume, using a full-scale test room and a breathing thermal manikin. The impacts of the ventilation system were illustrated by comparing the velocity distribution of the exhalation airflows and airflows induced by thermal plume. Further experiments employing two breathing thermal manikins were carried out to evaluate the interpersonal transport of the expiratory contaminants that were simulated by tracer gas. When the two manikins with the same heights were standing face to face at a mutual distance of 0.8 m, the exhalation airflows from the mouth of the source manikin could directly travel into the breathing region of the susceptible manikin, resulting in a high exposure. The high exposure decreased sharply with an increase in the mutual distance from 0.5 m to 1.0 m. Between 1.0 m to 3.0 m, the exposure by the susceptible manikin remained at a low and constant level.
Numerical simulations considering droplet evaporation and droplet nucleus sizes were carried out; and the impacts of the parameters of droplet initial size, humidity, vicinity, ventilation conditions and synchronization of exhalation were evaluated. Fine droplets and droplet nuclei were predicted to travel toward the upper part of the test room, whereas large droplets tend to be deposited on the floor. With a high relative humidity, 95%, most of the droplets were deposited on the floor within 16 seconds. Meanwhile, all of the droplets evaporated to droplet nuclei and remained suspended in the air when the relative humidity was 35%. Mixing ventilation that supplied fresh air with a ventilation rate of 5.6 h-1 resulted in drafts and strong turbulence, which made droplets and droplet nuclei dispersed in the room. The average vertical position was higher than that when the ventilation rate was 3.0 h-1. Displacement ventilation led to the vertical temperature stratification in the room. The vertical temperature gradient could neutralize the buoyancy force and weaken body plumes and the vertical dispersion of droplets and droplet nuclei.
The inhalation of the droplets and droplet nuclei by the susceptible person and the deposition of the droplets and droplet nuclei on the body surface of the susceptible person were investigated at mutual distances of 0.5, 1.0, 1.5 and 3.0 m. For one breath from the source person, 1,600 droplets were released. Three and 9 droplet nuclei were inhaled by the susceptible person at a mutual distance of 0.5 and 1.0 m, respectively. No droplet nuclei were inhaled at 1.5 and 3.0 m.published_or_final_version
Mechanical Engineering
Doctoral
Doctor of Philosophy
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Xie, Xiaojian, and 解晓健. "Evaporation and movement of respiratory droplets in indoor environments." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40987802.
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Lin, Kaisen. "Viability of Viruses in Suspended Aerosols and Stationary Droplets as a Function of Relative Humidity and Media Composition." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97955.
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The transmission of some infectious diseases requires that pathogens can survive (i.e., remain infectious) in the environment, outside the host. The viability of pathogens that are immersed in aerosols and droplets is affected by factors such as relative humidity (RH) and the chemical composition of the liquid media, but the effects of these stressors on the viability of viruses have not been extensively studied. The overall objective of this work was to investigate the effects of RH and media composition on the viability of viruses in suspended aerosols and stationary droplets. We used a custom rotating drum to study the viability of airborne 2009 pandemic influenza A(H1N1) virus across a wide range of RHs. Viruses in culture medium supplemented with material from the apical surface of differentiated primary human airway epithelial cells remained equally infectious for 1 hour at all RH levels tested. We further investigated the viability of two model viruses, MS2 and Φ6, in suspended aerosols and stationary droplets consisting of culture media. Contrary to the results for influenza virus, we observed a U-shaped viability pattern against RH, where viruses retained their viability at low and extreme high RHs, but decayed significantly at intermediate to high RHs. By characterizing the droplet evaporation kinetics, we demonstrated that RH mediated the evaporation rate of droplets, induced changes in solute concentrations, and modulated the cumulative dose of solutes to which viruses were exposed as droplets evaporated. We proposed that the decay of viruses in droplets follows disinfection kinetics. Lastly, we manipulated the chemical composition of media to explore the stability of viruses as a function of pH and salt, protein, and surfactant concentrations. Results suggested that the effects of salt and surfactant were RH and strain-dependent. Acidic and basic media effectively inactivated enveloped virus. Protein had protective effect on both non-enveloped and enveloped viruses. Results from this work has advanced the understanding of virus viability in the environment and has significant implications for understanding infectious disease transmission.Doctor of Philosophy
Pathogenic organisms, including bacteria, viruses, fungi, protozoa, and helminths, cause infections that are responsible for substantial morbidity and/or mortality. For example, it is estimated that influenza has caused 9 million to 45 million illnesses and 12,000 to 61,000 deaths annually since 2010 in the United States. The spread of certain diseases relies on people touching the pathogenic organism on surfaces or inhaling it from the air. Successful transmission requires that the pathogen survive, or maintain its infectivity, while it is in the environment. The survival of pathogens can be affected by temperature, humidity, composition of the respiratory fluid carrying them, and other factors. However, there is limited research investigating the effects of these factors on the survival of viruses in the environment. In this work, we studied the effect of relative humidity (RH) on the survival of viruses, including influenza virus and two other types of viruses, in inhalable aerosols and larger droplets. We found that influenza viruses survive well in aerosols across a wide range of RH levels for at least 1 h. Conversely, the two model viruses survived best at both low and very high RHs, such as found indoors in the wintertime or in tropical regions, respectively, but had a pronounced decay at intermediate RHs. By measuring how fast droplets evaporated, we found that RH affected their chemistry and determined the total amount of stress that viruses were exposed to. This explained why a "U-shaped" survival pattern was observed against RH. We also investigated the survival of viruses in droplets containing different components. Results indicated that the effects of salt, surfactant, protein, and droplet pH depended on RH and the type of virus. The outcomes of this work are meaningful in predicting the survival of viruses in aerosols and droplets of various compositions in the environment and could provide insight on developing strategies to minimize the spread of infectious diseases.
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Wan, Man Pun. "Indoor transport of human expiratory droplets in association with airborne infectious disease transmission using a multiphase-flow approach /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?MECH%202006%20WAN.
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Lützow, Joel, and Cecilia Mikiver. "Simulation of airborne transmission of infection in a confined space using an agent-based model." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280336.
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As the world observes a new pandemic with COVID-19, it is clear that pathogens can spread rapidly and without recognition of borders. Outbreaks will continue to occur, and so the diseases’ transmission method must be thoroughly understood in order to minimize their impact. Some infections, such as influenza, tuberculosis and measles are known to be spread through droplets in the air. In a confined space the concentration can grow as more droplets are released. This study examined a simulated confined space modelled as a hospital waiting area, where people who could have underlying conditions congregate and mix with potentially infectious individuals. It further investigated the impact of the volume of the waiting area, the number of people in the room, the placement of them as well as their weight. The simulation is an agent-based model (ABM), a computational model with the purpose of analysing a system through the actions and cumulative consequences of autonomous agents. The presented ABM features embodied agents with differing body weights that can move, breathe and cough in a ventilated room. An investigation into current epidemiological models lead to the hypothesis that one may be implemented as a corresponding ABM, where it could possibly also be improved upon. In this paper, it is shown that all parameters of the Gammaitoni and Nucci model can be taken into account in an ABM via the MASON library. In addition, proof is produced to suggest that some flaws of the epidemiological model can be mended in the ABM. It is demonstrated that the constructed model can account for proximity between susceptible people and infectors, an expressed limitation of the original model.När världen observerar en ny pandemi, COVID-19, är det tydligt att patogener kan spridas fort och utan hänsyn till landsgränser. Utbrott kommer att fortsätta ske och därför måste sjukdomarnas överföringsmetod förstås, så att deras påverkan kan minimeras. Det är känt att vissa infektioner, såsom influensa, tuberkulos och mässling kan spridas via droppkärnor i luften. I ett begränsat utrymme kan koncentrationen växa när fler droppar tillförs. Denna studie utvärderar ett simulerat begränsat utrymme modellerat som ett väntrum på ett sjukhus, där människor som kan ha underliggande sjukdomar samlas och beblandar sig med potentiellt smittsamma individer. Inverkan av volymen av väntrummet, antalet personer i rummet, var de var placerade i rummet samt deras vikt undersöktes också. Simuleringen är en agent-baserad modell (ABM), en beräkningsmodell med syftet att analysera ett system genom handlingarna och kumulativa konsekvenserna av självstyrande agenter. Personer med olika kroppsvikt som kan röra sig, andas och hosta i ett ventilerat rum simuleras i denna ABM. Efterforskning av aktuella epidemiologiska modeller leder till hypotesen att en sådan skulle kunna implementeras som en motsvarande ABM, där den möjligtvis också kan förbättras. I denna rapport kommer det att uppvisas att alla parametrar av Gammaitonioch Nucci-modellen kan tas hänsyn till i en ABM via MASON biblioteket. Därtill produceras bevis som pekar på att vissa brister i den epidemiologiska modellen kan hämmas i denna ABM. Det demonstreras att den konstruerade modellen kan beakta distansen mellan mottagliga personer och smittsamma, vilket är en känd begränsning i originalmodellen.
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Forster, Jeri E. "Varying-coefficient models for longitudinal data : piecewise-continuous, flexible, mixed-effects models and methods for analyzing data with nonignorable dropout /." Connect to full text via ProQuest. Limited to UCD Anschutz Medical Campus, 2006.
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Thesis (Ph.D. in Biostatistics) -- University of Colorado at Denver and Health Sciences Center, 2006.Typescript. Includes bibliographical references (leaves 72-75). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;
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Thompson, James Russell. "Imaging the assembly of the Staphylococcal pore-forming toxin alpha-Hemolysin." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:e320004a-6118-4dac-af2a-eca6e90be7ac.
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Alpha-hemolysin is a pore-forming toxin secreted by pathogenic Staphylococcus aureus. Its spontaneous oligomerization and assembly into a trans-bilayer beta-barrel pore is a model for the assembly of many other pore-forming toxins. It is studied here in vitro as a means to probe general membrane protein oligomerization and lipid bilayer insertion. This thesis details the results of experiments to develop and implement a novel in vitro lipid bilayer system, Droplet-on-Hydrogel Bilayers (DHBs) for the single-molecule imaging of alpha-hemolysin assembly. Chapter 2 describes the development of DHBs and their electrical characterization. Experiments show the detection of membrane channels in SDS-PAGE gels post-electrophoresis and DHBs use as a platform for nanopore stochastic sensing. Chapter 3 describes the engineering and characterization of fluorescently-labelled monomeric alpha-hemolysin for use in protein assembly imaging experiments described in Chapter 6. Chapter 4 describes the characterization of DHB lipid fluidity and suitability for single-molecule studies of membrane protein diffusion. In addition, a novel single-particle tracking algorithm is described. Chapter 5 describes experiments demonstrating simultaneous electrical and fluorescence measurements of alpha-hemolysin pores embedded within DHBs. The first multiple-pore stochastic sensing in a single-lipid bilayer is also described. Chapter 6 describes experiments studying the assembly of alpha-hemolysin monomers in DHBs. Results show that alpha-hemolysin assembles rapidly into its oligomeric state, with no detection of long-lived intermediate states.
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Kašpárková, Kateřina. "Nákazy přenášené kapénkami: znalosti, postoje a chování žáků 2. stupně základní školy." Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-446566.
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The diploma thesis deals with droplet infections and finds out what knowledge, attitudes and behavior pupils of the lower secondary school have towards them. The theoretical part focuses on educational documents in the Czech Republic, including the occurrence of topics about droplet infections in RVP ZV, didactic game as a teaching method and a detail description of selected viral and bacterial droplet infections. In the practical part, the diploma thesis finds out what knowledge, attitudes and behavior students have about droplet infections. Subsequently, a didactic game is performed and the effectiveness of the didactic game is evaluated by comparing the pre-test and the post-test on the basis of changes in the knowledge, attitudes and declared behavior of the interviewed pupils. The results showed that due to the didactic game there was an improvement in the students knowledge and a desired change of attitudes. The declared behavior of students remained unchanged, as the entry level of students in this area was already at a high level.
Books on the topic "Droplet infections"
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Russi, Mark. Biological Hazards. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190662677.003.0016.
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This chapter describes various biological hazards and their impact on workers and others. A major focus of the chapter is biological hazards in healthcare and laboratory settings, including exposure to bloodborne pathogens and prevention of diseases related to them. Sections deal with sharps injuries, HIV/AIDS, hepatitis B virus, hepatitis C virus, tuberculosis, and other infectious diseases that can be acquired in the work environment via direct contact, droplet or airborne spread, or fecal-oral transmission. In addition, infectious agents spread by animal contact or arthropod vectors in a broad range of settings will be addressed. Newly emerging infectious or re-emerging infections, such as those due to H5N1 and novel H1N1 influenza, Middle Eastern respiratory syndrome (MERS), and Ebola Virus Disease (EVD) as well as agents associated with bioterrorism are discussed.
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Purandare, Amol, and Barbara A. Jantausch. Parvovirus. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190604813.003.0012.
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Parvovirus B19 is a common infection in humans that occurs worldwide. Parvovirus B19 is transmitted through exposure to respiratory droplets, blood, and blood products, and through mother-to-child transmission (MTCT) in utero. Intrauterine parvovirus B19 infection is a rare occurrence during pregnancy but can result in significant morbidity and mortality for the fetus, including severe fetal anemia and nonimmune fetal hydrops (NIFH). Intrauterine transfusion can be successful in treating fetal anemia. Neurodevelopmental impairment has been reported in infants with congenital infection who have received intrauterine transfusion (IUT). Future research on the development of antiviral agents for the treatment of parvovirus B19 infection in pregnant women is needed, along with the development of a parvovirus B19 vaccine. Longitudinal studies to evaluate neurodevelopmental outcome of infants with a history of congenital parvovirus B19 infection are needed in order to facilitate the optimal evaluation and management of these infants.
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Spinner, Gary F., Jean R. Anderson, Joseph A. Church, Renata Arrington-Sanders, Aroonsiri Sangarlangkarn, Paul W. DenOuden, Madeline B. Deutsch, et al. Issues in Specific Patient Populations. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190493097.003.0013.
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It is estimated that 61% of new HIV infections are transmitted by patients who have either dropped out of care or are not taking their medications. In order to improve patient adherence and retention-in-care, efforts to enhance trust in health care providers require a broader understanding of the diversity and cultures of many different groups of patients with HIV. Children, adolescents, women, older patients, transgender patients, incarcerated patients, homeless patients, and rural and migrant patients represent special populations the care of which requires cultural competency and awareness of their special needs. Becoming competent in developing a clinician–patient relationship across cultural differences is very important.
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Anest, Trisha, and David Scordino. Plague. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199976805.003.0065.
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Plague has three distinct clinical forms. Bubonic plague may resemble many viral syndromes; a distinct feature is buboes. Buboes are swollen lymph nodes filled with multiplying bacteria. They form near the bacteria’s entry point into the bloodstream. Septicemic plague symptoms can include abdominal pain and shock, with bleeding into skin and internal organs. Tissue manifestations include fingers, toes, or other areas turning black and necrotic. Bubonic and septicemic forms are transmitted by flea bites or the handling of infected animals. Pneumonic plague is easily transmitted from human to human by the inhalation of infectious droplets. Pneumonic plague is often lethal, resulting in respiratory failure and shock. Antibiotic treatment should be started as soon as plague as suspected. A vaccine, which is no longer being manufactured, was effective against the bubonic plague but not pneumonic plague. Research is ongoing for a vaccine effective against pneumonic plague, the form most likely to be utilized as a biological weapon.
Book chapters on the topic "Droplet infections"
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Andersen, Bjørg Marit. "Airborne/Droplet Infection Isolation." In Prevention and Control of Infections in Hospitals, 187–96. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-99921-0_18.
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Fonseca, César, Ana Ramos, Sílvia Lopes, Dora Santos, Sónia Silveira, and André Antunes. "Noninvasive Ventilation and Droplet Dispersion: Health Professional Protocols from a Nursing Perspective." In Noninvasive Ventilation in High-Risk Infections and Mass Casualty Events, 289–304. Vienna: Springer Vienna, 2013. http://dx.doi.org/10.1007/978-3-7091-1496-4_33.
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Bhattacharyya, Anwesha, and Vineet Choudhary. "Lipidomics to Study the Role of Lipid Droplets in Host-Pathogen Interactions." In Integrated Omics Approaches to Infectious Diseases, 425–40. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0691-5_23.
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Klettner, C. A., I. Eames, and J. W. Tang. "The Effect of Turbulence on the Spreading of Infectious Airborne Droplets in Hospitals." In ERCOFTAC Series, 141–52. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-2506-5_9.
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Armstrong, Richard M., and Thomas C. Zahrt. "Mycobacteria Infection and Lipid Droplets: Host and Pathogen Stealing, Sharing and Storing Fat." In Tuberculosis Host-Pathogen Interactions, 201–29. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-25381-3_9.
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"Nursing patients with infectious diseases." In Oxford Handbook of Adult Nursing, edited by George Castledine and Ann Close, 695–732. Oxford University Press, 2009. http://dx.doi.org/10.1093/med/9780199231355.003.0020.
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Nursing assessment of patients with infectious diseases 696 Nursing problems 697 Specific tests and investigations 698 Blood-borne and droplet infections 700 Faeco-oral infections 702 Infections with resistant organisms 704 Infestations 706 Serious rare infections 708 Prevention of infection 711 Hand decontamination 712 Aseptic technique 714...
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Hsu, Desmond, and Zahir Osman Eltahir Babiker. "Geographical Pattern of Infectious Diseases and Infection Prevention for Travellers." In Tutorial Topics in Infection for the Combined Infection Training Programme. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198801740.003.0071.
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Infectious diseases are transmitted either directly from person to person via direct contact or droplet exposure, or indirectly through a vector organism (mosquito or tick) or a non-biological physical vehicle (soil or water). Vector-borne infectious diseases are highly influenced by climate factors such as temperature, precipitation, altitude, sunshine duration, and wind. Therefore, climate change is a major threat for the emergence and re-emergence of infectious diseases, e.g. re-emergence of dengue fever in some parts of southern Europe. The natural reservoirs of infectious diseases are either humans (anthroponoses) or animals (zoonoses). Population movement due to travel or civil unrest risks introducing non-immune populations to regions that are endemic for certain infectious diseases. By contrast, global trade contributes to the movement of animals or arthropods across the world and this poses a major risk for introducing infectious diseases to previously non-endemic settings, e.g. rats on board commercial ships and the global spread of hantaviruses; international trade in used car tyres and the risk of introducing flavivirus-infected mosquitoes into non-endemic settings; and the contribution of migratory birds to the introduction and the spread of West Nile virus in the United States. The unprecedented growth of international travel facilitates the swift movement of pathogens by travellers from one region to another. The main determinants of travel-related infections are destination country, activities undertaken during travel, and pre-existing morbidities. Therefore, the pre-travel consultation aims to assess potential health hazards associated with the trip, give advice on appropriate preventative measures, and educate the traveller about their own health. Attitudes towards seeking pre-travel health advice vary by the type of traveller. For example, those visiting friends and relatives (VFRs) in their country of origin are less likely to seek pre-travel health advice compared to tourists and therefore stand a higher chance of presenting with preventable infections such as malaria. The key aspects of a pre-travel consultation include: ● comprehensive risk assessment based on the demographic and clinical background of the traveller as well as the region of travel and itinerary.
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Harrison, Dr Mark. "Streptococci and Staphylococci." In Revision Notes for MCEM Part A, 163–66. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199583836.003.0013.
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1.1 Streptococci, 163 1.2 Staphylococci, 165 • Gram positive cocci • Facultative anaerobes • Encapsulated, alpha haemolytic cocci • Methods of spread - ▪ Streptococcus pneumoniae is a common nasopharyngeal commensal ▪ Spread is by droplet ▪ Exogenous (respiratory droplet spread from carrier infecting another host) or endogenous (carrier develops impaired resistance to organism) infection may occur...
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Jacob, George, and Martina N. Cummins. "The Concept of Chain of Infection and Infection Control Principles." In Tutorial Topics in Infection for the Combined Infection Training Programme. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198801740.003.0027.
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For an infectious agent to spread to cause disease, certain conditions must be present. This process is called the chain of infection, which consists of six links: ● Causative agent; ● Infectious reservoir; ● Path of exit; ● Mode of transmission; ● Path of entry; and ● Susceptible host. Infection can occur when all six links are intact. By breaking this chain, the spread of infection can be stopped. ● Causative agent A micro- organism capable of causing infection is called a causative agent. Most commonly they are bacteria, viruses, fungi, and parasites. ● Infectious reservoir A reservoir of infection is the source from which infection can spread by allowing the pathogen to survive and possibly multiply. Humans, animals, and even inanimate environmental objects can serve as reservoirs of infection. There are many sources of infection in a healthcare setting. These include patients, healthcare workers, visitors, inanimate objects like medical equipment, and even the hospital environment. A human reservoir can be either an infected case, or a carrier, i.e. the person is colonized by a particular pathogen and does not present with any symptoms or signs of acute infection. Adherence to standard infection control practices is important as these asymptomatic carriers present a risk of cross infection, especially in healthcare surroundings. ● Path of exit The path of exit is how a pathogen leaves its reservoir. It normally refers to the site where the micro- organism grows. Common sites of exit associated with human reservoirs include the skin, mucous membranes, and the respiratory, gastrointestinal, and genitourinary tracts. ● Mode of transmission The mode of transmission is the route by which an infection spreads. Certain pathogens may use more than one route of transmission from reservoir to host. There are three common modes of transmission. This is the most common mode of infection transmission in a healthcare setting. It can occur either through direct contact when there is direct physical contact with the patient or indirect contact when the pathogen is transmitted from a contaminated intermediate object. Infection spreads through the airborne route when the susceptible person inhales infected particles in droplet nuclei of less than 5 μm.
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Camus, Gregory, Dorothee A. Vogt, Andrew S. Kondratowicz, and Melanie Ott. "Lipid Droplets and Viral Infections." In Methods in Cell Biology, 167–90. Elsevier, 2013. http://dx.doi.org/10.1016/b978-0-12-408051-5.00009-7.
Full textConference papers on the topic "Droplet infections"
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Ersahin, C., I. B. Celik, W. G. Lindsley, and D. G. Frazer. "Aerosol Generation and Entrainment Model for Cough Simulations." In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98100.
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Coughing produces aerosols comprised of components of fluid that line the respiratory tract. These aerosols have been implicated in the transmission of many infectious diseases. Important factors that must be considered in aerosol transport include its physical size distribution, the shape and density of its components, as well as its chemical and biological composition. This study represents the initial phase of a larger project whose goal is to investigate the relationship between the generation of infectious aerosols and the dissemination of diseases in the workplace. The objective of this study was to develop a computational model representative of the generation and entrainment of an aerosol during cough. This model is composed of two sub-models; the first describes the formation of “mother” droplets and their entrainment in an air-stream and the second simulates the fragmentation of these droplets into smaller size distributions. The first sub-model is used to calculate the amount of fluid entrained in the droplets which is a function of the physical properties of the airway lining fluid and airflow patterns in the airway. The second sub-model describes the fragmentation of the droplets as a function of the physical properties of the fluid composition and a description of the flow field surrounding the droplet. Preliminary results show that, with the proper choice of model constants, it is possible to obtain relatively good agreement between model predictions and experimental measurements.
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Zayas, Jose G., Ming C. Chiang, Eric Wong, Fred MacDonald, Carlos Lange, Ambikaipakan Sentilselvan, and Malcolm King. "Improving The Quality Of Interventions To Control Infectious Cough Aerosol Droplets." In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a2885.
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Katramiz, Elvire, Nesreen Ghaddar, and Kamel Ghali. "Effect of Intermittent Personalized Ventilation on Coughed Particles Dispersion in an Office Space and Resulting Cross Contamination." In ASME 2021 Heat Transfer Summer Conference collocated with the ASME 2021 15th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/ht2021-60817.
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Abstract The transmission of infectious respiratory diseases has been a topic of broad interest for decades. It is largely influenced by the ventilation in the space, especially localized ventilation near the infection source. One energy-friendly ventilation technique that has been extensively investigated in contaminants transmission is Personalized Ventilation (PV), which delivers cool clean air directly towards the breathing zone of the user, procuring acceptable levels of thermal comfort and breathable air quality. However, when used by an infected person, it might amplify the dispersion of the expiratory droplets, increasing the risk of airborne cross-infection. Some PV applications varied the supplied cool clean air intermittently in order to enhance occupants’ thermal comfort and improve energy performance. Such system operation is referred to as Intermitted PV (I-PV). Nonetheless, the effect of such oscillatory jet on airborne diseases dispersion has not been assessed in literature to the authors’ knowledge. In this work, the impact of integrating I-PV with mixed ventilation on cross-contamination is investigated for the case where an infected user is coughing. The I-PV is considered to operate at an average flowrate of 10 l/s, with a minimum of 4 l/s at a typical frequency of 0.94 Hz. The infected person is considered seated in a tandem (i.e. back-to-face) position with respect to a healthy person, located at a distance of 1.5 m and not using PV. This reflects the worst-case scenario where the healthy person is not protected by PV. A validated computational fluid dynamics (CFD) model is used to assess the cross-contamination between the occupants. A comparison between I-PV and steady PV (S-PV) of constant flowrate of 10 l/s is conducted to highlight the influence of I-PV on contaminants dispersion in the space and the resulting exposure level of a healthy occupant. Results showed that the use of I-PV reduced the exposure levels of the healthy occupant in comparison to S-PV.
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Kuzman, Boris, and Biljana Petković. "ADAPTIVE NEURO FUZZY ESTIMATION OF THE OPTIMAL COVID-19 PREDICTORS FOR GLOBAL TOURISM." In The Sixth International Scientific Conference - TOURISM CHALLENGES AMID COVID-19, Thematic Proceedings. FACULTY OF HOTEL MANAGEMENT AND TOURISM IN VRNJAČKA BANJA UNIVERSITY OF KRAGUJEVAC, 2021. http://dx.doi.org/10.52370/tisc2194bk.
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COVID-19 is a pandemic that has emerged as a result of 2019-novel coronavirus droplet infection (2019-nCoV). Recognition of its risk and prognostic factor is critical due to its rapid dissemination and high casefatality rate. Tourism industry as one of the greatest industries has suffered a lot in the pandemic situation. The main aim of the study was to present travelers’ reaction during the pandemic by data mining methodology. The effect of eleven predictors for COVID-19 was also analyzed. The used predictors are: population density, urban population percentage, number of hospital beds, female and male lung size, median age, crime index, population number, smoking index and percentage of females. As the output factors, infection rate, death rate and recovery rate were used. The analyzing procedure was performed by adaptive neuro fuzzy inference system (ANFIS). The results revealed that the frequency of the used words in the pandemic show the highest impact on the travelers’ reactions. Number of hospital beds and population number is the optimal combination for the best prediction of infection rate of COVID-19.
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Bahl, Prateek, Charitha de Silva, C. Raina MacIntyre, Shovon Bhattacharjee, Abrar Ahmad Chughtai, and Con Doolan. "Video: Respiratory droplets and aerosols: capturing their dynamics to understand its implications on infection transmission." In 73th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2020. http://dx.doi.org/10.1103/aps.dfd.2020.gfm.v0044.
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Al-Asmar, Jawaher, Sara Rashwan, and Layla Kamareddine. "The use of Drosophila Melanogaster as a Model Organism to study the effect of Bacterial Infection on Host Survival and Metabolism." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0186.
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Enterobacteriaceae, a large family of facultative anaerobic bacteria, encloses a broad spectrum of bacterial species including Escherichia coli, Salmonella enterica, and Shigella sonnei, that produce enterotoxins and cause gastrointestinal tract diseases. While much is known about the regulation and function of enterotoxins within the intestine of the host; the lack of cheap, practical, and genetically tractable model organisms has restricted the investigation of others facets of this host-pathogen interaction. Our group, among others, has employed Drosophila melanogaster, as a model organism to shed more light on some aspects of host-pathogen interplays. In this project, we addressed the effect of Escherichia coli, Salmonella enterica, and Shigella sonnei infection on altering the metabolic homeostasis of the host. Drosophila melanogaster flies were orally infected with Escherichia coli, Salmonella enterica, or Shigella sonnei, a method that mimics the natural route used by enteric pathogens to gain access to the gastrointestinal tract in humans. The results of our study revealed that both Escherichia coli and Shigella sonnei pathogens were capable of colonizing the host gut, resulting in a reduction in the life span of the infected host. Escherichia coli and Shigella sonnei infected flies also exhibited altered metabolic profiles including lipid droplets deprivation from their fat body (normal lipid storage organ in flies), irregular accumulation of lipid droplets in their gut, and significant elevation of systemic glucose and triglyceride levels. These metabolic alterations could be mechanistically attributed to the differential down-regulation in the expression of metabolic peptide hormones (Allatostatin A, Diuretic hormone 31, and Tachykinin) detected in the gut of Escherichia coli and Shigella sonnei infected flies. Salmonella enterica; however, was unable to colonize the gut of the host; and therefore, Salmonella enterica infected flies exhibited a relatively normal metabolic status as that of non infected flies. Gaining a proper mechanistic understanding of infection-induced metabolic alterations helps in modulating the pathogenesis of gastrointestinal tract diseases in a host and opens up for promising therapeutic approaches for infection induced metabolic disorders
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Habchi, Carine Hanna, Kamel Ghali, and Nesreen Ghaddar. "Transient Model for Particle Dispersion Generated by High Momentum Respiratory Activities in Spaces Ventilated by Displacement Ventilation System." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50255.
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A transient zonal model wit is developed to study particle distribution resulting from transient respiratory activities in spaces ventilated by displacement ventilation system (DV). Two transient sub-models are coupled: a transport model of exhaled particles computing the percentage of generated particles penetrating the infected thermal plume and tracking the exhaled jet propagation, and a transport model predicting particle exchange between the different affected layers and regions. A parametric study was performed to determine the effect of different factors on the risk of cross-infection between the occupants: exhalation velocity, DV flow rate, distance separating the occupants and particle diameter. It was observed that with the increase of the DV flow rate, the ventilation effectiveness increases reducing particle accumulation in the breathing zone. The risk of cross-contamination becomes higher for reduced separating distance between the occupants, and for increased cough velocity, as the momentum of released droplets and their quantity increase. Therefore, it was found that to reduce cross-infection, measures can be considered as avoiding getting close to an infected occupant and covering the mouth during a cough. In addition, assisting DV system by chair fans is expected to reduce cross-contamination by increasing the strength of the rising thermal plumes.
Reports on the topic "Droplet infections"
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Samsudin, Ely Zarina, Siti Munira Yasin, Nurhuda Ismail, Muhammad Rodi Isa, Nasaruddin Abd Rahman, Ahmad Fitri Abdullah Hair, Dayanath A/L Manivasagam, and Nur Fateh Alia Rosli. Law enforcement and preparedness for airborne and droplet borne infectious diseases in industries: A systematic review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, September 2021. http://dx.doi.org/10.37766/inplasy2021.9.0049.
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Samsudin, Ely Zarina, Siti Munira Yasin, Mohamad Rodi Isa, Nik Nairan Abdullah, Nur Hasanah Ruslan, Ahmad Fitri Abdullah Hair Hair, Dayanath Manivasagam, and Nur Aina Syazwani Zakaria. Socioeconomic and Occupational Safety and Health Impact of Airborne and Droplet Borne Infectious Diseases in Industries: A Systematic Review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, September 2021. http://dx.doi.org/10.37766/inplasy2021.9.0055.
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