LECTURE XXXV. 

 TEXAS OR TICK FEVER.* 



Economic importance. — The seriousness of tick fever as a 

 disease of cattle and the bearing of this disease upon the southern 

 cattle industry was not realized until within a few years. Today 

 we know that it is responsible for the death of more cattle through- 

 out the southern states than any other half dozen diseases. Even 

 at this time its true nature is not generally recognized by the 

 stockmen. 



Names. — This disease passes under a variety of names, such 

 as acclimation fever, red water, bloody murrain, distemper, town- 

 cow disease, hollow horn, hollow tail, etc. 



Causes. — It has been established that the disease is caused 

 by an animal parasite, a protozoan, which attacks the red cor- 

 puscles of the blood. Little or nothing is known of the life his- 

 tory of this parasite outside of the blood of the afifected animal. 

 Its multiplication in the blood is very rapid and its effects are very 

 destructive, involving especially the red blood corpuscles. It de- 

 stroys these very rapidly. 



Transmission. — So far as known the only natural means of 

 transmitting the germ of this disease is the southern cattle tick 

 (BoopJiilus annul at lis) "f. Other species of ticks attack southern 

 cattle, but this is the most common and is the only one responsible 

 for the transmission of the Texas Fever germ. 



The ticks do not carry the germs direct from one infected ani- 

 mal to another, but the female ticks develop on infected animals 

 and then transmit the germs to their eggs and the young ticks 

 hatching therefrom carry the germs to susceptible animals, which 

 they may chance to infest. 



Susceptibility. — Bovines alone seem susceptible to the disease 

 although the tick, which carries the infection, occasionally infests 



•This lecture contributed by Dr. Tait Butler of North Carolina. 

 +Or B—Bovis (Riley). 



