448 INFECTIOUS DISEASES DUE TO PROTOZOA 



Prognosis. — If the cattle are immediately taken off the 

 infested pastures and all ticks removed from them recovery 

 usually follows in about two weeks, provided the attack has 

 been acute. ' On the other hand, where the animals are left 

 on the infested fields or where the outbreak has been very 

 severe, the patients die, the disease assuming a chronic form 

 , with symptoms of anemia, emaciation, and cachexia. 



Treatment. — The removal of the cattle from the infested 

 pastures and the eradication of the ticks (oil dips) are 

 essential. Internally individual patients are treated symp- 

 tomatically. 



Prophylaxis. — Tick-infested pastures should be avoided. 

 Tile draining and tilling such fields are indicated. Where 

 this is not possible the brush should be cut off and the fields 

 burned over as recommended in Texas fever. Dipping the 

 ticky cattle is indicated. 



Protective Inoculation. — The value of protective inocula- 

 tion (3 c.c. of fresh calf's blood) is still in dispute. In some 

 outbreaks the inoculation material seemed too weak and in 

 others too strong. 



East African Coast Fever (Rhodesian Red Water). — Defi- 

 nition.: — East African fever is a form of piroplasmosis in 

 cattle due to the Piroplasma parvum. Contrary to Texas 

 fever it cannot be artificially transmitted by blood. 



Occurrence. — The disease occurs along the East African 

 coast where it has existed for a long time in a latent form. 

 It has spread into the interior and has caused great losses 

 among the cattle of Transvaal and Rhodesia. 



Etiology. — The disease is caused'by the Piroplasma parvum, 

 a small rod-like protozoon. Several varieties of ticks, which 

 in the earlier stages of their development have sucked the 

 blood of infected cattle (Rhipicephalus appendiculatus, R. 

 Evertsi, sinus, nidens, and capensis) are responsible for its 

 spread. The parasite does not pass through the egg as in the 

 case of Texas fever, and the disease cannot be transmitted 

 from immune animals to healthy cattle. The infection takes 

 place only among young cattle when on pasture. Adult 

 animals are immune. As noted, the disease cannot be trans- 

 mitted by the blood, although transmission has been accom- 



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