HAEMOSPORIDIA 289 



Leucocytozoon ziemanni (Laveran). In the little owl, Athene 

 noctna. 



Family 3 Babesiidae Poche 



The members of this family are minute and non-pigmented 

 parasites of the erythrocytes of various mammals. They are 

 transmitted from host to host by ticks. Numerous genera have 

 been proposed. 



Genus Babesia Starcovici. Body pear-shaped. Arranged in 

 couples. Multiplication by binary fission. 



Babesia bigemina (Smith and Kilborne) (Fig. 122, g). The 

 organism of the "Texas fever" (or Red-water fever) of cattle. 

 The very first demonstration that an arthropod plays an im- 

 portant role in the transmission of a protozoan parasite. The 

 infected cattle contain in their erythrocytes oval or pyriform 

 bodies, in which a compact nucleus and vacuolated cytoplasm 

 are noted. The division is peculiar in that it appears as a bud- 

 ding process at the beginning. No other stages are known. The 

 arthropod which transmits the organism is the tick belonging 

 to the genus Margaropus. The tick remains fixed to one host 

 during its entire growth period, but drops off to lay eggs. The 

 infection is carried through the egg and embryo, and the young 

 ticks which find a new host cattle are already infected. The 

 Texas fever once caused a considerable amount of damage to 

 the animal industry in the southern United States. 



Babesia bovis Starcovici (Fig. 122, h). A much smaller 

 form which occurs in European cattle. 



Babesia are also known to occur in pigs, sheep, goats, horses, 

 dogs, and other mammals. 



Genus Theileria Bettencourt, Franga, and Borges. Unlike 

 Babesia, Theileria do not multiply actively in the erythrocite. 

 The schizogony takes pice in the endothelial cells of the capil- 

 laries of the spleen, liver, and other organs. The members are 

 parasites of mammals. 



Theileria parva (Theiler) (Fig. 122, i). The cause of a cattle 

 fever in Africa, known as the "East Coast fever," which differs 

 from theTexas fever. The organism is transmitted by cattle ticks. 



Genus Cytamoeba Labbe. Small amoeboid, structureless 

 organism occurring sometimes in amphibian erythrocytes. 



Cytamoeba bacterifera Labbe. In frogs of Europe and America. 



