Sneezing, and Disinfection by Hypochlorites

Bourdillon, R. B.; Lidwell, O. M.; Lovelock, J. E.

doi:10.1136/bmj.1.4227.42

Cited by 17 publications

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“…These calculated figures accord well with the figures obtained by Hare (1940), in direct observations of the expulsion of haemolytic streptococci in the mouth-spray of throat carriers; haemolytic streptococci were found to be contained in only a small proportion, from .0-3 to 3-5 %, of the expelled droplets, and, apparently, in none of the droplets small enough to form droplet-nuclei. namely, about 20,000 (Wells, 1935), about 100,000 (Bourdillon, et al 1942), and from 4500 to 150,000, on average 39,000 (Duguid, 1945). For a cough with the mouth initially closed, the calculated number of bacteria-carrying droplet-nuclei was 710; for speaking loudly one hundred words, it was 36.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…for those of 17 ,. The persistence of aerial infection following sneezing has been studied by Bourdillon, Lidwell & Lovelock (1942); after a few sneezes in quick succession were performed in a small room, the air was examined at intervals with a slit sampler (Bourdillon, Lidwell & Thomas, 1941), an instrumerit which is probably the most convenient and efficient of the modem air-sampling devices. The number of bacteria-carrying droplet-nuclei which remained airborne after sneezing was found to decrease geometrically with time; only 4 % remained airborne after 30 min.…”

Section: Introductionmentioning

confidence: 99%

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The size and the duration of air-carriage of respiratory droplets and droplet-nuclei

1946

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1. The sizes of the droplets and droplet-nuclei produced by sneezing, by coughing and by speaking, were studied by the microscopic measurement of 12,000 droplet stain-marks found on slides exposed directly to mouth-spray, and of 21,000 stain-containing droplet-nuclei recovered from the air on to oiled slides exposed in the slit sampler.2. From these measurements it was calculated that the original diameters of the respiratory droplets ranged from 1 to 2000 μ, that 95 % were between 2 and 100 μ and that the most common were between 4 and 8 μ. Similar size distributions were exhibited by the droplets produced in sneezing, in coughing and in speaking, except that, in the case of sneezing, the smaller droplets were relatively more numerous.3. The respiratory droplet-nuclei were found to range in diameter from ¼ to 42 μ; 97 % had diameters between ½ and 12μ; the commonest diameter was between 1 and 2 μ.4. The proportion of droplets of each size which will contain bacteria, whether commensal or pathogenic, is determined by the size of the droplets and by the numbers of bacteria in the secretions atomized. Calculations made on the basis of the size distributions obtained in this investigation indicated that few of the smaller droplets, and thus few of the droplet-nuclei, are likely to contain pathogenic organisms. Droplet-spray is unlikely to give rise directly to true airborne infection unless very large numbers of pathogenic organisms are present in the secretions of the anterior mouth.5. The persistence of droplet-nuclei in the air of a 1700 cu.ft. room and of a 70 cu.ft. chamber was investigated by sampling the air with the slit sampler at intervals following sneezing.6. When the air was not artificially disturbed by a fan, the time taken for the disappearance from the air of 90% of the bacteria-carrying droplet-nuclei varied from 30 to 60 min.; the nuclei larger than 8 μ in diameter usually disappeared within 20 min., and the nuclei larger than 4 μ within 90 min.; the smaller nuclei, few of which contained bacteria, remained airborne for much longer periods, on one occasion for at least 30 hr. When a fan was run throughout the experiment, the nuclei disappeared from the air much more rapidly.

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Section: Discussion Of Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The size and the duration of air-carriage of respiratory droplets and droplet-nuclei

1946

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“…Air Sampling.-On four occasions during the winter, samples were collected from the air for bacteriological analysis with a slit-sampler modified from those described by Bourdillon et al (1948). Two different counts of airborne bacteria are recorded in the tables.…”

Section: Methodsmentioning

confidence: 99%

“…Hexylresorcinol was recommended for use as an air disinfectant by Twort and Baker (1942). Bourdillon et al (1948), in their comparative study of a variety of possible disinfectant agents, showed that as little as 2 ,Ag. per cu.…”

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confidence: 99%

Trial of Hexylresorcinol as Air Disinfectant for Prevention of Colds in Office Workers

Lidwell¹,

Williams²

1954

BMJ

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“…We know something about the rate at which bacteria from mouth and nose are contributed to dust (Bourdillon, Lidwell & Lovelock, 1942;Hamburger, Green & Hamburger, 1945; Duguid, 1946;Dumbell, Lovelock & Lowbury, 1948). We also have information on the death-rate of such bacteria in dust under various environmental conditions (Cornet, 1889;Garrod, 1944; Lidwell & Lowbury, 1950).…”

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The persistence of dust in occupied rooms

Lowbury

1950

J. Hyg.

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Various factors are involved in determining the possible role of dust as a vehicle of infection. We know something about the rate at which bacteria from mouth and nose are contributed to dust (Bourdillon, Lidwell & Lovelock, 1942;Hamburger, Green & Hamburger, 1945; Duguid, 1946;Dumbell, Lovelock & Lowbury, 1948). We also have information on the death-rate of such bacteria in dust under various environmental conditions (Cornet, 1889;Garrod, 1944; Lidwell & Lowbury, 1950). It would be a further link in the chain of evidence to know how quickly dust is removed from occupied rooms. An attempt to obtain such information is described in this paper. METHODSSmall amounts of insoluble fluorescein were dispersed from an insufflating bottle into the air of twelve bedrooms used by volunteers at the Common Cold Research Unit. On the following day the volunteers were asked to sweep and collect the dust from the floor of their bedrooms, and to continue doing so daily. The complete sweepings each day were weighed and extracted by shaking in bottles containing 10 ml. of decinormal sodium hydroxide and glass beads. After 10 min. centrifugation at 2000 r.p.m. the supernatant was removed, and the fluorescence of a suitable dilution was matched in daylight against a standard range of fluorescein solutions.The optimum range in the fluorescein standard was between the 9th and 15th tubes in a series of doubling dilutions of 0 05 g. 'insoluble' fluorescein dissolved in 10 ml. decinormal sodium hydroxide. The dilutions were colourless when held up to the light but were clearly fluorescent. More concentrated solutions were coloured and showed little obvious difference in fluorescence in adjacent tubes. Matching of dust samples containing little fluorescein was difficult because of the green or brown colour of undiluted extracts. Quantitative assessment of these specimens was impossible, and where fluorescence was obvious they were recorded as containing a 'trace'.The physical properties of fluorescein cannot be assumed to correspond with those of house dust. An attempt was made to overcome this difficulty by saturating a piece of blanket material in a concentrated solution of fluorescein in decinormal sodium hydroxide, washing the blanket in decinormal hydrochloric acid to precipitate fluorescein, and then in water to rinse. The blanket was dried in the incubator at 370 C., and then beaten vigorously in two of the volunteers' bedrooms. As the duist obtained from bedrooms contains a large proportion of recognizable J. Hygiene

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Sneezing, and Disinfection by Hypochlorites

Cited by 17 publications

References 0 publications

The size and the duration of air-carriage of respiratory droplets and droplet-nuclei

The size and the duration of air-carriage of respiratory droplets and droplet-nuclei

Trial of Hexylresorcinol as Air Disinfectant for Prevention of Colds in Office Workers

The persistence of dust in occupied rooms

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