864 PATHOGENIC MICROORGANISMS 



the Spirochseta Novyi, 44 the organism studied by Norris and Flour- 

 noy and Pappenheimer, and regarded as a different species by them. 



Pathogenicity. Inoculation with blood containing these spiro- 

 chaetes 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 

 temperature which occurs abruptly as is the case in the disease 

 in man and which may last several days. During this 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. Occasionally, 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 animals relapses have been observed. Gross patholog- 

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

 of the spleen. 



In man the disease caused by the spirochaete of Obermeier and 

 allied organisms commonly known as relapsing fever, is common 

 in Eastern Europe, India, Africa, and most of the warmer countries. 

 It has, from time to time, been observed epidemically in Europe, 

 especially in Eussia, 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 generalized pains. Together with the rise of temperature, which 

 often exceeds 104 F., there are great prostration and occasionally 

 delirium. 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, w^hich 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 



**Novy and Fraenlcel, cited from Noguchi. 



