228 Arthropods as Essential Hosts of Pathogenic Protozoa 



Banks has designated it as Dermacentor venustus and this name is 

 used in the pubHcations 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 (191 1) has shown experimentally that spotted fever may 

 be transmitted by several different species of ticks, notably Dermacen- 

 tor marginatus, Dermacentor variabilis and Atnblyomma 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 (191 1) 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 alony 

 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 

 pubHcations 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 Vallej'. 



