A system of practical medicine. By American authors. Vol. 1

by Unknown

Occupation exerts no predisposing influence, but in all epidemics the great majority of cases occur among the vagrant classes, who lead a precarious life and commonly sleep in foul, overcrowded lodgings. Murchison noted that in the London epidemics a considerable proportion of cases occurred among recent residents, but he attributed this, correctly, not to any special local cause, but merely to the fact that this floating population is largely of the vagrant type. In Philadelphia a careful inquiry showed that recent residence produced no special predisposing influence, and a study of other epidemics confirms this view.

Contagion is, however, the essential cause of the spread of relapsing fever when the virus has once been developed. It seems clear from the distinct periods and from the widely-separated localities in which different outbreaks of relapsing fever have occurred that its special poison is capable of being called into existence or activity by favoring conditions. Murchison held the belief that it was very intimately connected with, if not generated by, destitution, and, as already stated, much evidence exists to show that the disease is most apt to break out after periods of scarcity; but no just and convincing proof exists that destitution, any more than over-crowding and other depressing influences, can actually engender a specific contagium capable of being transported to great distances and of originating widespread outbreaks of the specific disease among differently situated populations. It appears necessary to assume the existence of some unknown special virus which finds its suitable nidus for development in the conditions attendant on filth and overcrowding, and which attacks with greatest facility the systems of those who are enfeebled by want and depressed by vitiated air. When once this specific poison has been called into active existence, however, there can be no doubt as to the fact that it can be carried by fomites, and that it is given off from the bodies of relapsing-fever patients so as to affect any who may approach. Although a few observers have doubted this contagiousness of relapsing fever, the evidence in its favor is overwhelming. In many epidemics, as in Philadelphia in 1869, its contagiousness is at least as intense as that of typhus fever. A single case may, indeed, be admitted to a healthy family among the better classes or into the wards of a well-ventilated hospital without propagating the disease, although striking cases of contagion are on record where a patient has communicated the disease to all the members of a family favorably situated and living at a distance from any other possible source of contagion. On the other hand, if admitted to an overcrowded and filthy lodging the disease is apt to spread rapidly. Wyss and Bock report seventy-one cases as having occurred in a single lodging-house during the course of the Breslau epidemic of 1868, and in Philadelphia single houses in several instances furnished more than a score of cases, and several short streets more than one hundred cases each.

In the Philadelphia Hospital twenty-three persons lying sick in the wards with other affections contracted relapsing fever from the patients admitted with that disease; two of the visiting staff, five resident physicians, and nine nurses also suffered attacks of varying severity. This corresponds with the general experience of those connected with fever hospitals during the prevalence of relapsing fever.

As in the case of typhus and other contagious diseases, the distance at which relapsing fever can be contracted by direct contagion through the atmosphere is a very short one, not exceeding a few feet at most.

The poison may be carried by fomites. Instances are on record where persons having visited infected districts have conveyed the disease to others at a distance without contracting it themselves.

When rooms which have been occupied by relapsing-fever patients are subsequently occupied by other persons, these are very liable to acquire the disease. Parry relates two remarkable cases in which relapsing fever was transported to a distance by infected clothes; and it has been more than once observed that during epidemics of this disease laundry-women engaged in washing the clothes of fever patients, but without any means of more direct communication with the sick, were frequently attacked (Cormack, Wyss and Bock).

In connection with the etiology of relapsing fever it is necessary to consider the rôle played by a minute organism which has been frequently detected in the blood of patients suffering with this disease. This spiro-bacterium was first observed in relapsing fever by Obermeier⁷ in 1873, and has since been identified as a spirillum or spiroechete. The very numerous observations of Obermeier, Albrecht, H. V. Carter, Motschutkoffsky, Koch, Cohen, Holsti, Enke, Meschede, and others leave no doubt that this peculiar parasite does occur at least very frequently in the blood of patients with this disease. The failure to detect it, which has been reported by several good observers, may readily have been due to the extreme delicacy of the organism, or to the neglect of the proper method of preparing the slides of blood for examination, or to delaying the examination of the blood until after death, when it rapidly disappears. Thus no value can be attached to the negative observations of Rhoads and myself, made prior to Obermeier's discovery, since our method of examination was not sufficiently exact.

⁷ Centralbl. f. die med. Wissensch., 1873, No. 10.

The following description of the mode of examining the blood, and of the spirillum, is condensed from H. V. Carter's account: It is necessary to employ magnifying powers of not less than 500 diameters. The fresh blood may be examined immediately after obtaining it by pricking the washed finger of the patient. For preservation dried specimens are needed: a very thin layer of fresh blood is evenly spread with the needle over the glass cover, exposed to the weak fumes of a solution of osmic acid, and allowed to dry under protection from dust; the dried film of blood may then be treated with glacial acetic acid or may be stained.