Abstract
Distribution of types of C. diphtherias
H. D. WEIGHT has analysed the incidence, severity and age–distribution of 8,040 infections caused by the three types of Corynebacterium diphtheriœ (J. Path, and Bact., 52, 283–294; 1941). The cases were notified in Liverpool during the four years 1937–1940; and there were 475 deaths (5.9 per cent). The mitis type was cultivated from 29.8 per cent, the inter–medius type from 18.9 per cent, and the gravis type from 51.3 per cent of the total cases of diphtheria in the period under review. The figures show that the incidence of the gravis type increased each year from 34.2 per cent in 1937 to 69.6 per cent in 1940, but that the mitis and intermedius incidence correspondingly decreased. The proportion of the mitis cases in each year that were included within the age–group 0—4 was higher than that of the intermedius and the gravis cases in this age–period; and, similarly, the intermedius percentage figures were higher than those of the mitis type for the ages 10–14. The case–fatality rate, over the whole period, of infections with mitis was 2–2 per cent; for intermedius it was 10–7 per cent; and for gravis it was 6–3 per cent. The proportion of toxic cases was considerably greater in the intermedius and gravis groups than in the mitis group. The author discusses the validity of subdividing strains of the diphtheria bacillus into the above–mentioned types. This classification originated ten years ago in Leeds and has been widely confirmed, although critical reports have recently come from the United States. The Liverpool experience has convinced Wright that the types are founded on well–established criteria; that, with practice, they are readily distinguishable; and that they serve a useful purpose in helping to make clear the pathological and epidemiological features of the disease.
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Research Items. Nature 148, 55–57 (1941). https://doi.org/10.1038/148055a0
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DOI: https://doi.org/10.1038/148055a0