scholarly journals Studies on respiratory infection: III. Experiments with Brucella suis

1956 ◽  
Vol 54 (1) ◽  
pp. 49-57 ◽  
Author(s):  
H. A. Druett ◽  
D. W. Henderson ◽  
S. Peacock
Keyword(s):  
Particle Size ◽  
Guinea Pig ◽  
Respiratory Tract ◽  
Respiratory Infection ◽  
Airborne Particles ◽  
Brucella Suis

The infectivity of Brucella suis for the guinea-pig by the respiratory route has been studied. Br. Suis was dispersed in airborne particles of various sizes from single organisms to 12μ in diameter, and it was found that the infectivity decreased 600-fold with increasing particle size within this range. It is suggested that this is due to the ability of Br. Suis to multiply rapidly on the surface of the lower reaches of the respiratory tract.

scholarly journals Studies on respiratory infection: II. The influence of aerosol particle size on infection of the guinea-pig with Pasteurella pestis

1956 ◽  
Vol 54 (1) ◽  
pp. 37-48 ◽  
Author(s):  
H. A. Druett ◽  
J. M. Robinson ◽  
D. W. Henderson ◽  
L. Packman ◽  
S. Peacock
Keyword(s):  
Particle Size ◽  
Guinea Pig ◽  
Respiratory Tract ◽  
Respiratory Infection ◽  
Cross Infection ◽  
Airborne Particles ◽  
Small Particles ◽  
Large Particles ◽  
Aerosol Particle Size ◽  
Disease Characteristic

The LD50 dose of Past. pestis is much greater when tested by the respiratory route than by subcutaneous challenge. This is probably due to trauma inflicted on the airborne particles.Two forms of plague, both originating in the respiratory tract of the guinea-pig, can develop according to the size of the particle containing Past. pestis presented to the host. Small particles initiate a broncho-pneumonia which leads to septicaemia and death. Large particles establish a septicaemia, and death results more quickly without the development of a pneumonia.Cross-infection to normal animals occurs irregularly when they are exposed to others developing plague by the respiratory route. Such incident is rare when the initially infected animals are exposed to large particles. Cross-infected animals suffer from the disease characteristic of exposure to large particles. Attempts to establish an epizootic by cross-respiratory infection were abortive, probably due, in some measure, to the type of disease developing in first cross-infections.

scholarly journals Particle Size Effects on the Deposition Ratios of Airborne Particles in the Respiratory Tract

2004 ◽  
Vol 50 (2) ◽  
pp. 185-188 ◽  
Author(s):  
Kazutoshi Sugita ◽  
Sumio Goto ◽  
Osamu Endo ◽  
Daisuke Nakajima ◽  
Hirofumi Yajima ◽  
...  
Keyword(s):  
Particle Size ◽  
Respiratory Tract ◽  
Size Effects ◽  
Airborne Particles ◽  
Particle Size Effects

scholarly journals The respiratory retention of bacterial aerosols: experiments with radioactive spores

1953 ◽  
Vol 51 (3) ◽  
pp. 372-385 ◽  
Author(s):  
G. J. Harper ◽  
J. D. Morton
Keyword(s):  
Particle Size ◽  
Bacillus Subtilis ◽  
Guinea Pig ◽  
Respiratory Infection ◽  
Guinea Pigs ◽  
Particle Sizes ◽  
Bacterial Aerosols

The distribution of inhaled bacterial aerosols has been studied in guinea-pigs, monkeys and mice, using Bacillus subtilis spores labelled with radiophosphorus. Particle sizes from about 1 to 12μ have been used.The guinea-pig shows the expected change of distribution with particle size; the proportion retained in the head increases with increased particle size. The figures correspond closely with those for man. Monkeys show similar results but are more irregular.The subsequent fate of the retained particles has been studied and accords with what is known about ciliary removal.The work is intended to link with parallel investigations of respiratory infection in closely similar conditions, and its implications are discussed in a paper on that subject (Druett et al. 1953).

scholarly journals A novel box for aerosol and droplet guarding and evacuation in respiratory infection (BADGER) for COVID-19 and future outbreaks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hau D. Le ◽  
Gordon A. Novak ◽  
Kevin C. Janek ◽  
Jesse Wang ◽  
Khang N. Huynh ◽  
...  
Keyword(s):  
Respiratory Infection ◽  
Healthcare Providers ◽  
Airborne Particles ◽  
Risk Of Infection ◽  
Indirect Contact ◽  
Vacuum Suction ◽  
Qualitative And Quantitative ◽  
Additional Layer ◽  
Increased Risk ◽  
Design Construction

AbstractThe coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected millions and killed more than 1.7 million people worldwide as of December 2020. Healthcare providers are at increased risk of infection when caring for patients with COVID-19. The mechanism of transmission of SARS-CoV-2 is beginning to emerge as airborne spread in addition to direct droplet and indirect contact as main routes of transmission. Here, we report on the design, construction, and testing of the BADGER (Box for Aerosol and Droplet Guarding and Evacuation in Respiratory Infection), an affordable, scalable device that contains droplets and aerosol particles, thus minimizing the risk of infection to healthcare providers. A semi-sealed environment is created inside the BADGER, which is placed over the head of the patient and maintains at least 12-air changes per hour using in-wall vacuum suction. Multiple hand-ports enable healthcare providers to perform essential tasks on a patient’s airway and head. Overall, the BADGER has the potential to contain large droplets and small airborne particles as demonstrated by simulated qualitative and quantitative assessments to provide an additional layer of protection for healthcare providers treating COVID-19 and future respiratory contagions.

scholarly journals The BtaF Adhesin Is Necessary for Full Virulence During Respiratory Infection by Brucella suis and Is a Novel Immunogen for Nasal Vaccination Against Brucella Infection

2019 ◽  
Vol 10 ◽  
Author(s):  
Florencia Muñoz González ◽  
Gabriela Sycz ◽  
Iván M. Alonso Paiva ◽  
Dirk Linke ◽  
Angeles Zorreguieta ◽  
...  
Keyword(s):  
Respiratory Infection ◽  
Brucella Infection ◽  
Brucella Suis ◽  
Nasal Vaccination

A palpable chest wall mass in a 4-year-old boy

2021 ◽  
pp. e20200053
Author(s):  
Jakob M Domm ◽  
Joanne M Langley
Keyword(s):  
Chest Pain ◽  
Tract Infection ◽  
Respiratory Tract ◽  
Chest Wall ◽  
Respiratory Infection ◽  
Lower Respiratory Tract ◽  
Atypical Presentation ◽  
History Of ◽  
Wall Mass ◽  
Chest Wall Mass

Empyema necessitans (EN) is a rare but dangerous complication of a lower respiratory tract infection. The diagnosis can be difficult to make and therefore delayed. We describe a case of a child with an atypical presentation of EN. He was afebrile and without chest pain and presented with a palpable chest wall mass after a history of recent respiratory infection. The threshold of suspicion for EN should be low, and it must be suspected in all children with a chest wall mass and recent history of respiratory infection.

A theory of aerosol deposition in the human respiratory tract

1975 ◽  
Vol 38 (1) ◽  
pp. 77-85 ◽  
Author(s):  
D. B. Taulbee ◽  
C. P. Yu
Keyword(s):  
Particle Size ◽  
Respiratory Tract ◽  
Particle Deposition ◽  
Particle Concentration ◽  
Diffusion Mechanism ◽  
Aerosol Deposition ◽  
Lung Model ◽  
Brownian Diffusion ◽  
Human Respiratory Tract ◽  
Apparent Diffusion

The deposition of inhaled aerosol particles in the human respiratory tract is due to the mechanisms of inertia impaction, Brownian diffusion, and gravitational settling. A theory is developed to predict the particle deposition and its distribution in human respiratory tract for any breathing condition. A convection-diffusion equation for the particle concentration with a loss term is used to describe the transport and deposition of particles. In this equation, an apparent diffusion coefficient due to the velocity dispersion in the lung is present and found to be the dominant diffusion mechanism for the cases considered here. Expressions for deposition by various mechanisms are also derived. The governing equation is solved numerically with Weibel's lung model A. The particle concentration at the mouth is calculated during washin and washout and compared favorably with experimental recordings for 0.5-mum diameter di(2-ethylhexyl) sebacate particles. The total deposition in the lung for particle size ranging from 0.05 to 5 mum is also computed for a 500-cm-3 tidal volume and 15 breaths/min. The results in general agree with recent measurements of Heyder et al. However, a particle size of minimum deposition is found to exist theoretically near 0.3 mum.

scholarly journals Inward and outward effectiveness of cloth masks, a surgical mask, and a face shield

2020 ◽  
Author(s):  
Jin Pan ◽  
Charbel Harb ◽  
Weinan Leng ◽  
Linsey C. Marr
Keyword(s):  
Particle Size ◽  
Respiratory Tract ◽  
Filtration Efficiency ◽  
The Other ◽  
Woven Fabric ◽  
Protection Efficiency ◽  
Overall Efficiency

AbstractWe evaluated the effectiveness of 11 face coverings for material filtration efficiency, inward protection efficiency on a manikin, and outward protection efficiency on a manikin. At the most penetrating particle size, the vacuum bag, microfiber cloth, and surgical mask had material filtration efficiencies >50%, while the other materials had much lower filtration efficiencies. However, these efficiencies increased rapidly with particle size, and many materials had efficiencies >50% at 2 μm and >75% at 5 μm. The vacuum bag performed best, with efficiencies of 54-96% for all three metrics, depending on particle size. The thin acrylic and face shield performed worst. Inward protection efficiency and outward protection efficiency were similar for many masks; the two efficiencies diverged for stiffer materials and those worn more loosely (e.g., bandana) or more tightly (e.g., wrapped around the head) compared to a standard earloop mask. Discrepancies between material filtration efficiency and inward/outward protection efficiency indicated that the fit of the mask was important. We calculated that the particle size most likely to deposit in the respiratory tract when wearing a mask is ∼2 μm. Based on these findings, we recommend a three-layer mask consisting of outer layers of a flexible, tightly woven fabric and an inner layer consisting of a material designed to filter out particles. This combination should produce an overall efficiency of >70% at the most penetrating particle size and >90% for particles 1 μm and larger if the mask fits well.

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