ROCKY MOUNTAIN SPOTTED FEVER 189 



days. The disease begins with a general feeling of illness fol- 

 lowed by chills and aches. A constant fever gradually increases 

 until the tenth or twelfth day, when death is likely to occur. 

 In mild cases the fever gradually subsides during the five or six 

 days following. Usually on the third day a rose-colored rash 

 breaks out on the head and upper part of the body, followed a 

 day or two later by a characteristic spotting of the arms and 

 legs, and later of much of the body, caused by the bursting of 

 blood capillaries in the skin. The spots often become brownish 

 or grayish in color, giving the spotted appearance from which 

 the disease takes its name. In Montana, especially in the Bitter 

 Root Valley, the disease has a high fatality, 75 per cent or more 

 of the cases ending in death. The fatality is also high in eastern 

 Oregon, but in other endemic regions is very much lower. The 

 disease appears only in spring and early summer when ticks are 

 abundant. So far no specific remedy has been discovered. 



There is evidence that spotted fever may be harbored by some 

 of the wild mammals on which the wood tick normally occurs, 

 but this has not yet been proved. The transmitting tick, D. 

 venustus, is a species which requires two years to reach maturity. 

 In its immature stages it infests many of the local rodents, nearly 

 all of which are susceptible to the disease, and capable of trans- 

 mitting it to uninfected ticks. As adults the ticks live on many 

 of the larger wild animals and on domestic animals, especially 

 cattle and horses. Whether some of these animals may be 

 carriers of spotted fever has not been determined. 



Prevention of spotted fever consists primarily in fighting ticks 

 by various methods (see p. 368), and in destroying rodents, both 

 to reduce the number of host animals for the young ticks, and to 

 prevent the possibility of their acting as carriers of the disease. 



There is grave danger that spotted fever may be introduced 

 into other parts of the country where suitable ticks for trans- 

 mitting it can be found. The exportation by railroad of wild 

 deer, elk, goats or other tick-infested animals to zoological parks 

 or government preserves is a dangerous proceeding unless great 

 care is taken to destroy all ticks and to exclude any individuals 

 which might be harboring the disease germ. The occasional 

 occurrence of the disease in various parts of the United States 

 should be carefully watched for, and every precaution taken to 

 prevent local ticks from getting access to the infection. 



