372 The Diseases of Animals 
TEXAS, OR SOUTHERN CATTLE FEVER 
This disease is also called Spanish, splenic, acclima- 
tion, and (in Australia) “tick” fever. In some regions, 
owing to the color of the urine, the disease is called 
“redwater.” It is caused by a microscopic animal 
germ (Piroplasma bigeminum), and is transmitted from 
southern to susceptible northern cattle by means of 
the southern cattle-tick (Margaropus annulatus). Fig. 
52. Southern cattle coming from the region south of 
central Virginia and Tennessee, and east of central 
Indian Territory and Texas, and from Lower Cali- 
fornia, come from a permanently infected territory, 
and have the germs of Texas fever in their blood; but 
they do not suffer from Texas fever, as they possess 
immunity. The region described is south and east of 
the quarantine line established by the United States 
Department of Agriculture, and marks the northern and 
western limits of the region permanently infested by 
the southern cattle-tick. 
When southern cattle are brought north during the 
warm season of the year, the mature female ticks drop 
from their bodies and lay a great number of eggs that 
hatch in from two to six weeks. The young ticks 
are quite active and show a tendency to crawl up on 
grass rather than sidewise. When susceptible north- 
ern cattle pass over the tick-infested ground, these 
young ticks get on their legs, crawl up to their bodies 
and soon bury their mouth-parts in the thin skin on 
the belly or the inside of the thighs. In this manner 
they transmit the germs of the disease. About ten 
