Viability and Infectivity of Microorganisms in Experimental Airborne Infection

Goodlow, Robert J.; Leonard, Frederic A.

doi:10.1128/br.25.3.182-187.1961

Cited by 48 publications

(10 citation statements)

References 10 publications

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“…The results were independent of the number of spores in a particle. Goodlow and Leonard (1961) confirmed this finding with aerosol particles of Pasturella tularensis of different sizes. To produce 50% mortality in guinea pigs and rhesus monkeys required 3 and 17 cells of 1 /-Lm particle size, 6500 and 240 cells of 7 /-Lm particle size, 20,000 and 540 cells of 12 /-Lm particle size; and 170,000 and 3000 cells of 22 /-Lm particle size, respectively.…”

Section: Particle Size and Dose-responsesupporting

confidence: 72%

Health Aspects of Bioaerosols

Salem¹,

Gardner²

1994

Atmospheric Microbial Aerosols

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Section: Particle Size and Dose-responsesupporting

confidence: 72%

Health Aspects of Bioaerosols

Salem¹,

Gardner²

1994

Atmospheric Microbial Aerosols

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“…Here t m is the average thickness of the porous media. N d is the number of active pores in dry mask during penetration process and from volume conservation, and they showed N d ∼ (D/ ) 3 . Finally, we arrive at the scaling for the viscous dissipation as E d ∼ (μ l U D 5 t m )/ 4 .…”

Section: Hydrophobic Maskmentioning

confidence: 99%

“…In the analysis for the critical condition for penetration of dry masks as shown in Eq. ( 1), Sahu et al [31] evaluated the number of active pores participating in penetration as N d ∼ (D/ ) 3 , since only the pores under the droplet will be active [shown in Fig. 6(c)].…”

Section: Hydrophilic Masksmentioning

confidence: 99%

“…However, when wet, the neighboring pores which already contains liquid will also be active [shown in Fig. 6(c)], and as such, the active number of pores for wet mask will be given by N w ∼ (D w / ) 3 , where D w is the mean diameter of the wetted region [shown in Fig. 6(c)].…”

Section: Hydrophilic Masksmentioning

confidence: 99%

“…Respiratory droplets (both large drops and liquid aerosol particles) transmit various pathogens [1][2][3], including the SARS-Cov2 virus [4,5] responsible for the current Covid-19 pandemic, which has taken close to 45 M lives and infected close to 250 M people worldwide at the time of writing of this article [6]. Such droplets, when exhaled through the nasal and oral cavities of the infected individual during respiratory events such as speaking, singing, coughing, sneezing, etc., transport and carry the pathogens [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Penetration and secondary atomization of droplets impacted on wet facemasks

et al. 2021

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Face covering, commonly known as a facemask, is considered to be one of the most effective pieces of personal protective equipment to reduce transmissions of pathogens through respiratory droplets-both large droplets and liquid aerosol particles. Facemasks inhibit the expulsion of such respiratory droplets from the user and protect the user from inhaling pathogen-laden potentially harmful droplets or their dried nuclei. While the efficacies of various dry face masks have been explored in the recent past, a comprehensive investigation of a wet mask is lacking. Yet users wear masks for an extended period and, consequently, due to the deposition of respiratory droplets released through multiple respiratory events, the mask matrix becomes wet. We, herein, present an experimental study on the dynamics of sequential impacts of droplets on masks to understand how wetness affects possible penetration and secondary atomization of the impacted droplet. Two different types of masks, hydrophobic and hydrophilic, were used in this study to evaluate the underlying physical mechanisms that control the penetration in each of them.

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Deposition of Inhaled Aerosols

Stuart¹

1973

Arch Intern Med

106

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The development of theoretical models and the experimental studies that have been done describe the deposition of aerosols in the respiratory tract as a function of particle size and respiration patterns. Descriptions of the anatomical structure of the respiratory tract, air flows, and the physical behavior of airborne particles illustrate the basis of the various models of inhaled particle deposition. Particle density, shape, hygroscopicity, and pathology influence particle deposition, and the particle size distribution and deposition site of the inhaled aerosol influence the resultant biological response.The possible cause-and-effect rela¬ tionships between inhalation of airborne particles and pulmonary or systemic disease have been recog¬ nized for several hundred years. In 1556, Agricola described the condi¬ tions of mining in the region of Sax¬ ony and the pathological effects re¬ sulting from such work.1 In 1865, Siegle reported experiments indicat¬ ing penetration of airborne materials deep into the lungs.2 Zenker, in 1867, proposed the term "pneumonokoniosis" to describe the severe pulmo¬ nary diseases prevalent in dusty trades, including silicatosis, anthracosis, siderosis, and byssinosis.1 Shortly after the discovery of bac¬ teria a century ago, associations were suggested between the inhalation of airborne microorganisms and subse¬ quent development of tuberculosis4 and anthrax.5 At the beginning of the 20th century, the increased levels of pulmonary disease among miners of silica-bearing ores were ascribed to fine, hard particles of rock dust in the mine atmosphere.6 The critical role of particle size in the development of silicosis was indicated by the studies of Watkins-Pitchford and Moir, who found 80% of the particles in silicotic lungs to be less than 2ju.7 In 1923, Mavrogordato stated that phthisis was caused by free silica particles of 0.5]ii to 5|ii diameter.8 It is currently believed that the effective dose of quartz-bearing material needed to produce silicosis may be less than 1% of the total dust inhaled over many years. Exposure to aerosols of fresh, finely divided zinc oxide (< 0.6ju) pro¬ duces "metal-fume fever," but expo¬ sure for equal times to equal air con¬ centrations of zinc oxide particulates generated from a bulk volume may produce no detectable effect." Thus, it became increasingly evident that knowledge of the concentration of an airborne contaminant and the total inhaled air volume involved was not sufficient to reliably predict the physi¬ ological or pathological results of in¬ halation exposure. Further informa¬ tion was urgently needed concerning the depth of penetration and frac¬ tional removal of specific sized par¬ ticles to determine the critical sites of action, related clearance mechanisms, probability of infection by inhaled pathogens, and translocation and ex¬ cretion patterns of inhaled particu¬ late materials. This review begins with brief de¬ scriptions of the anatomical and physiological aspects of the lung that regulate airflow, and the basic physi¬ cal proces...

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Viability and Infectivity of Microorganisms in Experimental Airborne Infection

Cited by 48 publications

References 10 publications

Health Aspects of Bioaerosols

Health Aspects of Bioaerosols

Penetration and secondary atomization of droplets impacted on wet facemasks

Deposition of Inhaled Aerosols

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