336 



blue tick, transmits the disease, for this tick 

 transmits also Texas fever in South Africa. 



It is in this form of bovine piroplasma espe- 

 cially that atypical forms have been described by 

 Theiler,. and subsequently more fully by 

 Laveran. 



(i) Forms resembling straight or curved 

 bacilli,. one to three m long. They are thicker at 

 one end, which contains a chromatin particle. 

 One to four may occur in the same cell. 



(ii) Forms resembling cocci, singly or in 

 pairs. Two to four may occur in the same cell. 



@©© 



Fig. 75. Atypical forms of Piroplasma 

 {After Laveran) 



It is important to note that together with the 

 atypical forms typical [forms are always found, 

 though these latter may be rare. 



These atypical forms occur in the severe cases. 

 Similar cocci-like forms, described by Smith and 

 KiLBORNE in Texas fever, occurred in the slight 

 cases. The post-mortem lesions, characteristic of 

 this form of pirosomal disease, are local infarcts in 

 various organs. 



5. Piroplasma hominis. — This species of piro- 

 plasma is responsible for the disease known as 

 'spotted fever,' occurring in Montana and Idaho, 

 U.S.A., and possibly in Egypt. As the name 

 implies, there accompanies the fever an eruption 

 of spots. The mortality in the United States is 

 as high as seventy to eighty per cent. It is much 



