228 Arthropods as Essential Hosts of Pathogenic Protozoa 
Banks has designated it as Dermacentor vennstus and this name is 
used in the publications of the Bureau of Entomology. On the other 
hand, Stiles maintains that the common tick of the Bitter Root 
Valley, and the form which has been collected by the authors who 
have worked on Rocky Mountain spotted fever in that region, is 
separable from D. venustus, and he has described it under the name of 
Dermacentor andersoni. 
Maver (1911) has shown experimentally that spotted fever may 
be transmitted by several different species of ticks, notably Dermacen¬ 
tor marginatus , Dermacentor variahilis and Amblyomma americanum. 
This being the case, the question of the exact systematic status of 
the species experimented upon in the Bitter Root Valley becomes 
less important, for since Dermacentor occidentalis, Dermacentor 
venustus and Dermacentor andersoni all readily attack man, it is 
probable that either species would readily disseminate the disease 
if it should spread into their range. 
Hunter and Bishop (1911) have emphasized the fact that in the 
eastern and southern United States there occur several species which 
attack man, and any one of which might transmit the disease from 
animal to animal and from animal to man. The following species, 
they state, would probably be of principal importance in the Southern 
and Eastern States: the lone star tick ( Amblyomma americanum)] 
the American dog tick ( Dermacentor variabilis) ; and the gulf-coast 
tick ( Amblyomma maculatum). In the extreme southern portions of 
Texas, Amblyomma cajennense, is a common pest of man. 
Since the evidence all indicates that Rocky Mountain spotted 
fever is transmitted solely by the tick, and that some of the wild 
animals serve as reservoirs of the virus, it is obvious that personal 
prophylaxis consists in avoiding the ticks as fully as possible, and in 
quickly removing those which do attack. General measures along 
the line of tick eradication must be carried out if the disease is to be 
controlled. That such measures are feasible has been shown by the 
work which has been done in controlling the tick-borne Texas fever 
of cattle, and by such work as has already been done against the 
spotted fever tick, which occurs on both wild and domestic animals. 
Detailed consideration of these measures is to be found in the 
publications of the Public Health and Marine Hospital Service, 
and the Bureau of Entomology. Hunter and Bishopp give the 
following summarized recommendations for control or eradication 
measures in the Bitter Root Valley. 
