444 VETERINARY BACTERIOLOGY 



geese and other fowls; Sp. theileri, in cattle; and Sp. ovina, in 

 sheep. 



All the members of this group may be characterized as slender, 

 spiral threads, motile by sinuous movements, incapable of cultiva- 

 tion on ordinary media, and in some cases difficult to stain, 

 requiring special technic. 



Spirochaeta obermeieri 



Synonyms. Spiroschaudinnia recurrentis; Spirillum obermeieri; 

 spirillum recurrentis. 



Diseases Produced. Relapsing fever, recurrent fever, spirillosis 

 in man. 



Obermeier, in 1873, published his discovery of a large spiral 

 organism in the blood of patients suffering from relapsing fever. 

 Since that time it has been repeatedly observed, and several 

 similar species have been described infecting man, differing prin- 

 cipally in their pathogenicity for small animals, and the fact that 

 immunity to one does not immunize against the other. 



Distribution. The disease is known from Europe, and occurs 

 in isolated cases in many parts of the world. 



Morphology and Staining. Spirochceta obermeieri is a very 

 slender, tapering spiral. It is about 0.4 u in diameter, and varies 

 greatly in length. It is always many times as long as broad. 

 There are from two to ten spirals or turns in the organism, as 

 commonly observed. Opinions differ as to the presence of flagclla 

 and undulating membrane. It is motile, with a very rapid, screw- 

 like motion and a waving motion of the entire organism. The 

 organism may be observed in the living condition. It is best 

 stained by the Romanowsky method or some modification of it. 



Isolation and Culture. The organism has never been success- 

 fully cultivated upon ordinary media. Some multiplication may 

 take place in freshly drawn blood, but it does not long continue, 

 and its occurrence has been denied by some investigators. 



Pathogenesis. Experimental Evidence. The organism is path- 

 ogenic for man, monkeys, mice, and rats. The only practicable 

 method of maintaining a culture is by repeated transfers of the 

 organism from one animal to another. 



Character of Disease and 'Lesions. The disease in man is char- 



