PUBLIC HEALTH 



31 



ous disease with a quite high death-rate, but trench fever is 

 non-fatal and its importance in the war zones has been due 



Fig. 13b. Map illustrating the distribution of typhus fever in the new world. It is a common 

 disease in the regions marked with black, less common in those marked with cross-hatched lines 

 and rare in those marked with parallel lines, (.\fter Byam, el at.) 



to its great prevalence and the fact that persons affected with 

 it are incapacitated for extended periods. 



The louse is also responsible for the spread of relapsing 

 fever in Eurasia, North America, and northern Africa. This 



