# 1911 Encyclopædia Britannica/Relapsing Fever

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​RELAPSING FEVER (Febris recurrent), the name given to a specific infectious disease occasionally appearing as an epidemic in communities suffering from scarcity or famine. It is characterized mainly by its sudden invasion, with violent febrile symptoms, which continue for about a week and end in a crisis, but are followed, after another week, by a return of the fever.
This disease has received many other names, the best known of which are famine fever, seven-day, bilious relapsing fever, and spirillum fever. As in the case of typhoid, relapsing fever was long believed to be simply a form of typhus. The distinction between them appears to have been first clearly established in 1826, in connexion with an epidemic in Ireland.
Relapsing fever is highly contagious. With respect to the nature of the contagion, certain important observations have been made (see also Parasitic Diseases). In 1873 Obermeier discovered in the blood of persons suffering from relapsing fever minute organisms in the form of spiral filaments of the genus Spirochaete, measuring in length 1/500 to 1/1000 inch and in breadth 1/40000, to 1/50000 inch, and possessed of rotatory or twisting movements. This organism received the name of Spirillum obermeieri. Fritz Schaudinn has brought forward evidence that it is an animal parasite. The most constantly recognized factor in the origin and spread of relapsing fever is destitution; but this cannot be regarded as more than a predisposing cause, since in many lands widespread and destructive famines have prevailed without any outbreak of this fever. Instances, too, have been recorded where epidemics were distinctly associated with overcrowding rather than with privation. Relapsing fever is most commonly met with in the young. One attack does not appear to protect from others, but rather, according to some authorities, engenders liability.
The incubation of the disease is about one week. The symptoms of the fever then show themselves with great abruptness and violence by a rigor, accompanied with pains in the limbs and severe headache. The febrile phenomena are very marked, and the temperature quickly rises to a high point (105°–107° Fahr.), at which it continues with little variation, while the pulse is rapid (100–140), full and strong. There is intense thirst. a dry brown tongue, bilious vomiting, tenderness over the liver and spleen, and occasionally jaundice. Sometimes a peculiar bronzy appearance of the skin is noticed, but there is no characteristic rash as in typhus. There is much prostration of strength. After the continuance of these symptoms for a period of from five to seven days, the temperature suddenly falls to the normal point or below it, the pulse becomes correspondingly slow, and a profuse perspiration occurs, while the severe headache disappears and the appetite returns. Except for a sense of weakness, the patient feels well and may even return to work, but in some cases there remains a condition of great debility, accompanied with rheumatic pains in the limbs. This state of freedom from fever continues for about a week, when there occurs a well-marked relapse with scarcely less abruptness and severity than in the first attack, and the whole symptoms are of the same character, but they do not, as a rule, continue so long, and they terminate in a crisis in three or four days, after which convalescence proceeds satisfactorily. Second, third and even fourth relapses, however, may occur in exceptional cases. The mortality in relapsing fever is comparatively small, about 5% being the average death-rate in epidemics (Murchison). The fatal cases occur mostly from the complications common to continued fevers. The treatment is essentially the same as that for typhus fever. Lowenthal and Gabritochewsky by using the sgrum of an immune horse succeeded in averting the relapse in 40% of cases.