TICKS — BISHOPP 397 



TICK PARALYSIS 



In the Western States and in western Canada a number of children 

 have died from a form of ascending paralysis induced by the Rocky 

 Mountain spotted fever tick. This same species has been proved to 

 be capable of causing paralysis in sheep and dogs. While this dis- 

 ease is not common, it is one which is worthy of consideration. 



In Australia a distinct species of tick {Ixodes holocyclus Neum.) 

 has been found to cause a similar malady in man and sheep. In 

 South Africa still another tick, Ixodes pilosus Koch, causes a para- 

 lytic disease in sheep, and in Crete still other kinds of ticks appear 

 to be involved in the same way. 



The nature of the causative agent of tick paralysis is not known. 

 Some think this disease is due to a specific organism, and others that 

 a toxic material is introduced by the tick during its engorgement. 

 The symptoms usually develop during the latter part of the period 

 of engorgement, at the time blood is being taken in rapidly by the 

 parasite. Apparently only the adult ticks cause the malady. In 

 many cases the symptoms subside if the tick is removed before the 

 paralysis has progressed too far. 



OTHER TICK-BORNE DISEASES 



Ticks have been convicted of carrying many other diseases of ani- 

 mals. Fortunately a number of these do not occur in this country. 

 However, it is likely that some of them such as bilary fever of dogs 

 and spirochaetosis of chickens are present in this country and have 

 not been identified. It should be pointed out that we have well 

 established in this country the fowl tick and the brown dog tick, 

 which are carriers of these respective diseases. Through rigid quar- 

 antine some of the dangerous diseases have been prevented from 

 gaining a foothold in the United States. 



East Coast fever, one of the most formidable diseases of cattle in 

 South Africa, is carried by several distinct species of ticks. The 

 African disease known as heartwater of cattle, sheep, and goats is 

 transmitted by the so-called bont tick, Arnhlyomnia hehraeum Koch. 

 Fortunately the virus of this disease is not retained in the blood of 

 the animals after they recover. 



Other diseases related to splenetic fever of cattle and spirochaeto- 

 sis of fowls are transmitted among horses, sheep, and goats through 

 the agency of ticks. In India a disease of dogs known as canine 

 anemia has been shown by Dr. S. R. Christophers to be carried by 

 the brown dog tick, in the body of which the causative organism 

 goes through a portion of its life cycle. 



No attempt is made herein to catalog all of the diseases in the 

 transmission of which ticks play a part. It should be pointed out 



