CHAPTER L 



THE SPOTTED FEVER OF THE ROCKY 

 MOUNTAINS 



Synonyms — Definition — History — Climatology — ^Etiology — Morbid anatomy 



Symptomatology — Diagnosis — Prognosis — Treatment — Prophylaxis — 



The intermittent tick fever of Wyoming — References. 



SPOTTED FEVER OF THE ROCKY MOUNTAINS. 



Synonyms. — Black fever. Blue disease. Rocky Mountain spotted fever, 

 Spotted fever of Montana, Rocky Mountain fever, Piroplasmosis hominis, 

 Spotted fever of Idaho, Tick fever of the Rocky Mountains. 



Definition. — ^An acute endemic febrile disorder, associated with 

 a petechial or purpuric eruption of the skin, which occurs after the 

 bites of infected ticks, Dermacentor andersoni Stiles, 1905 (which 

 is the same as D. venustus Banks, 1908), and probably other ticks — 

 e.g., D.molestus and D, mafuratus — in certain regions of the Rocky- 

 Mountains. 



History. — -The first case of the disease is believed to have 

 occurred in Bitter Root Valley, in 1873, and from that date until 

 1902 it is said that about 200 cases were observed, with a mor- 

 tality of 70 to 80 per cent. During this period it was generally 

 known as the ' black fever,' the ' blue disease,' or the ' spotted 

 fever.' 



In 1898, according to Anderson, Major M. W. Wood made an 

 unpublished report on the disease to the Surgeon-General of the 

 United States Army. In 1899 Maxy wrote a paper on ' The So- 

 called Spotted Fever of Idaho,' which he described as an acute, 

 endemic, non-contagious, but probably infectious febrile disorder, 

 characterized clinically by a continuous, moderately high fever, 

 severe arthritic and muscular pains, and a profuse petechial or 

 purpuric eruption of the skin, appearing first on the ankles, wrists, 

 and forehead, but rapidly spreading to all parts of the body. In 

 1902 Gwim and McCullough read separate papers on the disease 

 at a meeting of the Montana State Medical Association, and in the 

 same year Wilson and Chowning were deputed to investigate it in 

 the Bitter Root Valley. As a result of their investigation, they 

 concluded that it was caused by a Piroplasma. They believed this 

 Piroplasma to be parasitic in a squirrel {Spermophilis columhianus) , 

 and to be spread to human beings by a tick, Dermacentor reticulatus 



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