Agglutinating and lytic substances show themselves chiefly during the apyretic intervals.
The spleen is enlarged and soft. There are frequent infarctions. The spirochaetes are found phagocytized in the macrophages of the spleen and elsewhere. Parenchymatous degeneration of kidney and heart muscle, and especially of liver, may be noted.
Symptomatology
East and West African Relapsing Fevers.—In African tick fever after a period of incubation of from three to ten days the disease sets in rather suddenly with dizziness, marked headache and general body pains. The temperature quickly rises to 104°-105°F. and remains elevated during this primary febrile period, except for slight morning remissions. Vomiting is quite a feature of this disease and may be bilious in character.
There may be rather marked praecordial oppression and a bronchial catarrh. The pulse in particular and the respiration in less degree are accelerated. Herpes and epistaxis may be noted. The bronchial manifestations seem to occur chiefly in the first febrile accession. The spleen is somewhat enlarged and tender but in many cases this is not noted. Spirochaetes are found in the peripheral circulation during the febrile accessions but not during the apyrexial intervals. There is great variation as to the abundance of spirochaetes. In some cases we may have to search several hundred fields before finding a single spirochaete. Severe cases may show them in abundance. A rather marked leucocytosis may be present in cases showing high fever and bronchitis. After about four days the fever falls by crisis, often below normal, and possibly with great prostration and cardiac weakness.
A critical sweat is a feature of this rapid fall of temperature. During the afebrile period, which lasts from three or four days to eight to ten days, the patient feels much better and his appetite and strength return. With the onset of the second pyrexial wave the severe symptoms of the first days are repeated, as with the first febrile period. This second one terminates by crisis. Iritis is not uncommon. Manson and Thornton have reported transient cranial nerve involvements coming on late in the course of the disease.
In European relapsing fever the second febrile accession is usually shorter and of less severity than the first. Furthermore there are rarely more than 2 or 3 relapses. In tick fever, however, there may be as many as 10 of these febrile recurrences, although there are usually only 4 or 5. In natives there is usually only one febrile period, this probably being due to an immunity resulting from previous infections.
North African Type.—In the relapsing fever of North Africa the attacks are less severe and the number of relapses rarely exceeds three. A fever of Egypt, generally known as the bilious typhoid of Griesinger, is believed to have been a form of relapsing fever. In this there was marked bilious vomiting with great tenderness of the liver, late jaundice, albuminuria, bone pains, especially about the knees, and a high death rate. The symptoms rather suggest yellow fever but this disease has never been reported from Egypt.
Indian Type.—In the relapsing fever of Asia there is a marked tendency for the patient to collapse at the time of the crisis. There are rarely more than two relapses and in probably 25% of cases there is no relapse. There seems to be a greater tendency to liver complications in the Asian types than elsewhere and such cases form a large part of the death rate from this disease. Bilious vomiting and jaundice, with a typhoid-like state and the occurrence of various inflammatory complications, especially parotiditis, are noted. The mind is usually clear, but delirium may be present in severe cases.
Relapsing Fever of Panama.—In three experimental cases the temperature of the first accession varied from 102°F. to 104.5°F. Frontal headache and general body aches were the chief symptoms. Vomiting was noted in one case. The spleen was not enlarged. The first relapse was cut short in each case by arsphenamine.