552 Relapsing Fever 



so that the eggs were commonly infected and the embryo 

 hexapod ticks hatched from them were infective. Thus, 

 in regard to Spirochaeta duttoni we are able to say quite 

 definitely that the tick is the usual if not the only means of 

 dissemination. 



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 Spiro- 

 chseta duttoni to be infectious for mice and rats, and attribute 

 the failure of others to discover this to their failure to exam- 

 ine the blood during the first and second days. Fulleborn 

 and Meyer and Martin f were able successfully 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 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 char- 

 acteristic. After a short incubation period the invasion 

 comes on with chill, fever, headache, pain in the back, 

 nausea and vomiting, and sometimes convulsions. The tem- 

 perature rises rapidly and there are frequent sweats. The 

 pulse is rapid. By the second day the temperature may be 

 104 to 105 F. and the pulse 1 10 to 130. There is enlargement 

 of the spleen. Icteroid discoloration of the conjunctiva 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 four- 

 teenth day the relapse characteristic of the affection makes 

 its appearance as an exact repetition of what has gone be- 

 fore. This is followed by another apyretic interval, and 

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

 * Loc. cit. t Loc. cit. 



