Human infection carriers, their significance, recognition and management

Preface

The volume which is herewith presented to the medical public is the outcome of the renewed interest which the subject of Infection Carriers has acquired since the outbreak of the great war, and the resulting necessity of guarding the health of our troops against epidemics. With this has come an evergrowing demand for men trained in the recognition of carriers by laboratory methods and for these, more particularly, the book has been written.

The request from the Surgeon-General's Office that medical students be thoroughly drilled in the epidemiological aspects of the infectious diseases, including the laboratory side of the question, has brought up the problem in what department this training should be given. At the University of Maryland Medical School and College of Physicians and Surgeons of Baltimore, the carrier question was taken up by the Department of Clinical Pathology, to which it would properly seem to belong. The extension of the usual clinical pathological work along these lines has been found most satisfactory from every standpoint. It has already proven of absorbing interest to the student, and will no doubt lead to corresponding work, as a matter of routine, in the clinical laboratories of our hospitals. In the past it has been a source of constant regret to the writer that the clinician and the laboratory worker in so many of our institutions are, for the good of the patient, not sufficiently in touch, and it is for this

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reason also, no doubt, that practically no sanitary work of any kind is either demanded or conducted in the majority of the hospital laboratories. It does not speak well for our institutions at which infectious diseases are treated which are apt to result in the development of the carrier state, that previous to the discharge of the patient no examination is made to ascertain whether or not he is apt to prove a menace to others. Team work is here urgently called for between the clinician and the worker in the clinical laboratory on the one hand, and the hospital authorities and the health department officials on the other. The amount of good that would result from such cooperation has been clearly brought out even during the brief period of time that work of this order has been carried on in our military camps, especially when directed by such men as stand at the head of our government sanitary service.

Much of the work and many of the methods which have been collected in this volume are of very recent date. In bringing together the data which seemed of interest and importance, the writer has attempted to be as thorough as possible, but even so, no doubt, many valuable papers may have been overlooked. If this be so, he asks forbearance on the part of his readers and promises to add what may yet be missing in a subsequent edition, if this should be called for.

A general idea of the arrangement of the subject matter may be found from a brief perusal of the table of contents. It will be noted that the book deals with a discussion of the problem under consideration only in connection with those diseases of bacterial origin or which are due to the activity of a filtrable virus in the dissemination of which healthy human carriers are now known to play a role, viz., carriers who either have never passed through an attack of the corresponding malady themselves, or, having done so, have

PREFACE V

clinically recovered. The maladies in question are cholera, diphtheria, typhoid and paratyphoid fever, dysentery, epidemic meningitis, poliomyelitis, pneumococcus pneumonia, certain streptococcus infections (such as camp septicemia, bronchopneumonia, septic sore-throat, erysipelas and puerperal fever), influenza, and possibly also the pneumonic form of plague.

Under these headings the various phases of the carrier problem have been discussed, i. e., the occurrence of active and passive carriers, the duration of the carrier state, the numerical relation between patients and carriers, the habitat and the virulence of the organisms, the mode of infection, concrete examples illustrating the danger of the carrier to others, the recognition of the carrier with a detailed description of the laboratory methods involved, and the management of the carrier from the standpoint of the public health officer. In conclusion, there have been appended the most important State laws, municipal ordinances, and federal interstate regulations dealing with the carrier problem which have been enacted up to January 1, 1918.

While the book was primarily written for students of medicine, it is hoped that it may prove of some service also to the health officer as well as to the general practitioner, without whose active aid and cooperation any material progress looking to the eradication of infectious diseases from our midst will be impossible.

Chakles E. Simon.

Baltimore, Md., 1919.

Contents

Introduction 17

Active and Passive Carriers 19

Virulence of Organisms 25