500 Relapsing Fever 



effect the transmission of micro-parasites is to a certain extent in 

 dispute. It was at first supposed that the spirochaetes entered the 

 human hosts with the saliva of the respective arthropods, but there 

 is some reason to think that this is a mistake, and that the scratch- 

 ing of the itching bite conveys the spirochaeta deposited upon the 

 skin in the excrement of the arthropod, into the deeper layers and 

 lymphatics through which it reaches the blood. 



Pathogenesis. 'The spirochaeta of relapsing fever are pathogenic 

 for man and monkeys, some of them for smaller animals. Novy 

 and Knapp* found their organism and Spirochaeta duttoni to be 

 infectious for mice and rats, and attribute the failure of others to 

 discover this to their failure to examine the blood during the first 

 and second days. Fulleborn and Meyer, and Martinf were able 

 successfuly to transmit .the spirochaeta of Russian relapsing fever 

 to mice after first passing it through apes. Rabbits and guinea- 

 pigs seem to be refractory; white mice susceptible. Man, monkeys, 

 and mice suffer from infection characterized by relapses, and in 

 them the disease may be fatal. Rats never die of the disease and 

 rarely have relapses. 



The micro-organisms are free parasites of the blood in which 

 they swim with a varying rapidity, according to the stage of the 

 disease. They are present during the febrile paroxysms only, 

 disappearing completely as soon as the crisis is reached. 



The course of relapsing fever in man is peculiar and characteristic. 

 After a short incubation period the invasion comes on with chill, 

 fever, headache, pain in the back, nausea and vomiting, and some- 

 times convulsions. The temperature rises rapidly and there are 

 frequent sweats. The pulse is rapid. By the second day the tem- 

 perature may be 104 to io5F. and the pulse no to 130. There 

 is enlargement of the spleen. Icteroid discoloration of the conjunc- 

 tiva may be observed. The fever persists with severity and the 

 patient appears very ill for five or six days, when a crisis occurs, 

 and the temperature returns to normal; there is profuse sweating 

 and sometimes marked diarrhea, and the patient at once begins to 

 improve. So rapid is the convalescence that in a few days he may 

 be up and may desire to go out. The disease is, however, not at 

 an end, for on or about the fourteenth day the relapse characteristic 

 of the affection makes its appearance as an exact repetition of what 

 has gone before. This is followed by another apyretic interval, 

 and then by another relapse, and so on. The patient usually re- 

 covers, the mortality being about 4 per cent. The fatal cases 

 are usually old or already infirm patients. The Indian, African, 

 and American varieties present variations of no great importance. 

 The European fever usually ends after the second or third relapse, 

 the African not until after a greater number. 



* Loc. cit. t Loc. cit. 



