The Distribution of the Diphtheria Bacillus and the Bacillus of Hofmann in the Throats of “Contacts” and Normal Persons

Abstract

1. Diphtheria bacilli have been found in a considerable proportion of persons who have come into contact with cases of diphtheria or with other infected persons.2. Such persons have been shown to be a grave danger to public health, especially when frequenting schools or institutions, and to constitute the usual channel by which the disease is spread.3. Very satisfactory results have followed on the isolation of convalescents from the disease and of infected “contacts,” where two or more consecutive negative examinations have been required before release.4. Carefully conducted investigations amongst healthy persons, who have not at a recent date been in contact with diphtheria cases or infected “contacts,” have shown that virulent diphtheria bacilli are very seldom (3 examples amongst 1511 persons) present in the mouths of the normal population. This fact renders the discovery and isolation of infected persons a practicable possibility and offers a fair prospect of discovering and isolating the majority of them in any outbreak.5. Diphtheria bacilli are usually distinguishable on morphological and cultural grounds, but whenever possible it is desirable that their virulence should be tested.6. The bacillus of Hofmann is innocuous to man, and is a very common organism in the mouths of the poorer classes. The distribution of this bacillus points to the conclusion that it is carried from mouth to mouth in the same way as the diphtheria bacillus, and therefore its widespread prevalence in schools attended by poorer children is significant, as showing how widely spread and uncontrollable an outbreak of diphtheria may become unless measures are early taken to deal with infected contacts.