SPIROCILETOSIS IN THE LOWER ANIMALS 719 



The serum of animals which have recovered from an attack of the disease exhibits 

 prophylactic properties and has a marked agglutinating action on the Spirochsetes 

 in vitro. 



3. Spirochaeta theileri. 



[S. theileri was discovered by Theiler in the blood of cattle about Pretoria.] 

 Laveran gave the first published description of the parasite. This spirochsota 

 measures 8-30/z long, shows a variable number of spirals and has no flagella. Cattle 

 infected with the spirochsete [often] show Trypanosom.es or Piroplasmata in the 

 blood in addition, and the presence of the Spirochsete is accompanied by certain 

 changes in the blood as for example nucleated erythrocytes and erythrocytes con- 

 taining basophile granules. 



The disease is transmitted by a tick (Theiler). His experiments were repeated 

 in France: A number of larvae of Boophilus (Rhipicephalits) decoloratus raised 

 from the eggs of a tick which had been fed upon an infected bovine in the 

 Transvaal were sent by Theiler to Laveran and Vallee who placed them on a cow 

 at the experimental farm at Alfort. The spirochaetes appeared in the blood of the 

 cow 14 days later but were only found for 4 days : 4 days later the cow developed 

 acute Piroplasmosis (P. bigeminum) and died. 



Spirochsetosis in the horse (Theiler), and in sheep (Theiler and Ziemann) which 

 also occur in the Transvaal are apparently due to infection with S. theileri (Dodd) 

 [but their identity cannot be regarded as established (Nuttall)]. 



