3° 



Insects and Disease 



The infection is not direct, that is, the tick does 

 not feed on one host then pass to another carrying 

 the disease germs with it. Unlike many other 

 ticks the Texas fever tick does not leave its host 

 until it is fully developed. When the female is full 

 grown and gorged she drops to the ground and lays 

 from 2,000 to 4,000 eggs which soon hatch into the 

 minute " seed-ticks" which make their way to the 

 nearest blade of grass or weed or shrub and 

 patiently wait for the cattle to come along. 



If the mother tick had been feeding on an animal 

 that was infected with the Texas fever parasite, 

 her body was filled with the minute organisms of 

 which some found their way into the eggs so that 

 the young ticks hatching from them were already 

 infected and ready to carry the infection to the first 

 animal they fed upon. 



It took many years of hard patient work to 

 learn all this, but the knowledge thus obtained 

 cleared up much of the mystery in connection 

 with the occurrence of the fever in the north and, 

 as we shall see, suggested the possibility of other 

 diseases being communicated in the same way. 



It was found that the southern cattle in the 

 region where the ticks occur normally, usually 

 have a mild attack of the disease when they are 

 young and although they may be infected with the 



