608 PATHOGENIC MICROORGANISMS 



are the Spirochaeta Duttoni, described by Button and Todd^ in 1905, the 

 Spirochseta Kochi, and the Spirochseta Novyi,^ the organism studied by 

 Norris and Flournoy and Pappenheimer, and regarded as a different 

 species by them. 



Pathogenicity. — Inoculation with blood containing these spirochaetes 

 produces disease in monkeys, rats, and mice. Attempts to transmit 

 the disease experimentally to dogs, rabbits, and guinea-pigs have so 

 far been unsuccessful. The subcutaneous inoculation of monkeys is 

 followed after from two to four days by a rise of temperatiu-e which 

 occurs abruptly as is the case in the disease in man and which may last 

 several days. Dm-ingthis time the spirochaetes can be found in the 

 blood of the animals just as it is found in that of infected human beings. 

 The temperature subsides after a day or more, when it again rapidly 

 returns to normal. As a rule, the paroxysms are not repeated. Occa- 

 sionally, however, two or three attacks may supervene before immunity 

 is established. In rats, an incubation time of from two to five days 

 occurs. At the end of this time the spirochaetes may be found in large 

 numbers in the blood, and the animals show symptoms of a severe 

 systemic infection. The attack lasts from four to five days, at the end 

 of which time the microorganisms again disappear. Occasionally even 

 in these aniraals relapses have been observed. Gross pathological 

 changes are not found, with the exception of an enlargement of the 

 spleen. 



In man the disease caused by the spirochsete of Obermeier, commonly 

 known as relapsing fever, is common in India, Africa, and most of the 

 warmer countries. It has, from time to time, been observed epidemically 

 in Europe, especially in Russia, and a few epidemics have occurred in 

 the Southern United States. The disease comes on abruptly, beginning 

 usually with a chill accompanied by a sharp rise of temperature and gen- 

 erahzed pains. Together with the rise of temperature, which often ex- 

 ceeds 104° F., there are great prostration and occasionally deUrium. Early 

 in the disease the spleen becomes palpable and jaundice may appear. 

 The spirochaetes are easily detected in the blood during the persistence 

 of the fever, which lasts usually from three to ten days. At the end 

 of this time the temperature usually drops as suddenly as it rose, and 

 the general symptoms rapidly disappear. After a free interval of 

 from one to three weeks a relapse may occur, which is usually less 

 severe and of shorter duration than the original attack. Two, three, or 



1 Dutton and Todd, Brit. Med. Jour., 1905. 

 ''■Novy and Fraenkel, cited from Noguchi. 



