14 THE ROCKY MOUNTAIN SPOTTED FEVER TICK. 
IMPORTANCE OF THE CONTROL OF THE SPOTTED-FEVER TICK. 
The most conspicuous loss from spotted fever is in human lives. 
In the Bitter Root Valley it was estimated in 1904 that 200 cases of 
the severe type of the disease had occurred up to that year. A con- 
servative estimate of the mortality there, as has been stated, is 70 
per cent. This means a loss of about 140 lives in this small valley. 
At the present time, with an increase in the population of the valley, 
it is estimated that about 20 cases of the disease occur annually. 
This means a loss of about 15 lives each year and this loss is certain 
to increase as the population of thé valley becomes larger. 
In Idaho it was estimated in 1908 by Dr. E. E. Maxey that the 
annual average of cases of spotted fever was 375. Undoubtedly, 
as Dr. Maxey pointed out, this estimate is very conservative. In all 
probability 500 would be a small estimate. The comparatively 
small mortality in Idaho would give a loss of human lives each 
year of about 35. 
_ Taking into consideration the whole area over which spotted fever 
is more or less prevalent, it is conservative to estimate 750 cases 
each year with probably 75 deaths. 
A great indirect injury the tick does in the Bitter Root Valley is 
in preventing the proper development of a region favored by a rich 
soil and by remarkable climatic advantages. As long as it is 
known that a dangerous disease exists there and that persons who 
farm or go into the country are especially subject to it, the valley 
can not prosper as it should. Relief from the tick would imme- 
diately result in increased land values and larger immigrations into 
the valley. 
In a larger way the possibility of the spread of the virulent form 
of the disease outside of the valley must be considered. This alone 
would warrant a much larger expenditure than is actually required 
for extermination or control in the valley. 
SUMMARY OF FACTS BEARING ON IMPORTANCE OF TICK CONTROL. 
Tt has been proved beyond peradventure by the investigations of 
Dr. Ricketts and others that spotted fever is transmitted in nature 
only by certain ticks. In the region where the disease now occurs 
it is transmitted to man by a single species of tick. Therefore the 
rational method of eradicating the disease is to attack this tick. In 
this way the proper procedure is exactly analogous to that being fol- 
lowed in the eradication of splenetie fever of cattle from the United 
States, by the eradication of the tick which transmits it. In the case 
of splenetic fever, certain more or less effective means of combating 
the disease itself have been discovered. These are in the form of a 
method of preventive inoculation and the administration of certain 
