Journal of Hygiene 

About: Journal of Hygiene is an academic journal. The journal publishes majorly in the area(s): Population & Virus. It has an ISSN identifier of 1469-4409. It is also open access. Over the lifetime, 4275 publications have been published receiving 94804 citations.

The estimation of the bactericidal power of the blood.

Abstract: The survival rate, p , of a measured inoculum of Staph aureus in a standard volume of denbrinated blood, is a reliable quantitative measure of the bactericidal power of blood The number of viable organisms in the inoculum and in the blood-bacterium mixture may be estimated with the necessary accuracy by counts of colonies developing from measured volumes of the fluids let fall on to the surface of solid media Fildes' agar was the most suitable medium for this surface-viable count, and was selected on the basis of four criteria; of the media tested it yielded the highest counts, and the counts conformed most closely to a Poisson series; and on it the mean colony size was maximum, and the coefficient of variation of colony size was minimum On this medium, the close conformity of the separate count values to a Poisson series enabled the standard error of the survival rate to be determined from a simplification of the general expression for the standard error of a ratio The number of colonies growing from a sample of a blood-bacterium mixture may be reduced, not by killing of the individual cocci, but as a result of their aggregation either by agglutinins in the blood, or in the cytoplasm of leucocytes that are phagocytic but not bactericidal It appears that these mechanisms are unlikely to operate in blood-bacterium mixture containing relatively few organisms; in such mixtures the survival rate is a reflexion of the killing power only The immunological significance of p has not been investigated, but the range of values for healthy human adults differs significantly from that for sufferers from chronic staphylococcal infection Moreover, by the technique employed differences may be detected between individual values of p that cannot reasonably be attributed to technical or sampling errors

The Significance of Pneumococcal Types.

Abstract: According to Avery's colleague and biographer, Rene Dubos, Griffith's findings in this article were like "exploding a bombshell in the field of pneumococcal immunology." In it, he described his observation of an experiment in which R cells of type I pneumococcus transformed into S cells of type II in the course of his experiment. Griffith's findings here were highly influential on several members of Avery's lab, including Martin Dawson and Lionel Alloway. This article was originally published in January 1928.

The role of serum haemagglutination-inhibiting antibody in protection against challenge infection with influenza A2 and B viruses.

Abstract: The intranasal inoculation of volunteers with living partially attenuated strains of influenza A and B viruses offers a new opportunity to determine the protective effect of serum haemagglutin-inhibiting antibody against a strictly homologous virus, under conditions where the time and dosage of the infective challenge can be controlled, the scoring of proven infections can be more precise and higher rates of infection can be achieved than in most natural epidemics.In 1032 adult volunteers, whose serum HI antibody titre was determined immediately before virus challenge, there was a consistent inverse quantitative relationship between the HI titre and the likelihood of infection. The PD 50 (50% protective dose) of HI antibody was 1/18-1/36, but an unusual finding was that volunteers with no detectable pre-challenge antibody often seem to be less susceptible to infection than those with pre-challenge antibody in low titre.In one group of volunteers challenged with an influenza B strain there was no evidence that pre-challenge antibody titres against viral neuraminidase had any significant protective effect against challenge infection.

Colonization resistance of the digestive tract in conventional and antibiotic-treated mice.

Abstract: The effect of oral administration of antibiotics on the intestinal flora of conventional mice and their resistance to colonization by orally introduced Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was studied. Colonization resistance (CR) was expressed as the log of the oral bacterial dose followed by a persistent take in 50% of the contaminated animals. The intestinal flora was virtually eliminated by the antibiotics and this elimination was accompanied by a precipitous fall of CR. CR gradually returned to normal values during the period of repopulation of the intestinal tract by the organisms surviving the treatment. Antibiotic treatment resulted in the disappearance of Enterobacteriaceae, enterococci, staphylococci and yeasts and, under appropriate housing conditions, the animals remained free of these organisms indefinitely. Germ-free mice contaminated with the intestinal flora of an antibiotic-treated animal and their offspring housed in a germ-free isolator showed high values of CR. Their intestinal flora consisted of anaerobic bacteria only. Apparently, these anaerobes are responsible for CR in these and in conventional mice.

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

Abstract: 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.