950 DISEASES CAUSED BY F1LTRABLE VIRUS 



since the possibilities here are the only ones that seem to show 

 great etiological promise at the present time. 



Prevention of trench fever, like the prevention of typhus, depends 

 upon delousing. 



ROCKY MOUNTAIN SPOTTED FEVER 



Rocky Mountain Spotted Fever is a disease which has long 

 existed in the United States. A thorough review of the entire 

 subject has been made by Wolbach 45 who states that authentic cases 

 were reported as early as 1873. The disease has been pretty well 

 limited to the mountainous regions, most of the cases being reported 

 from Idaho and Montana. 



The Disease. The onset of the disease is usually abrupt, though 

 occasionally it may be preceded by a few days of general malaise. 

 It not infrequently begins with a chill, followed by a rapid rise of 

 temperature which reaches 102 or 104. The temperature may 

 show morning remissions with rises of one or two degrees in the 

 evening, and gradually increasing, reaching its height during the 

 second week. On the third or fourth day after the onset of the 

 disease, a rash appears first on the wrists, ankles and back, later 

 upon the arms, legs and chest, extending to the forehead and 

 abdomen. It is always least marked on the abdomen, according 

 to Wolbach. It comes out in the course of about thirty-six hours 

 and may also involve the mucous membranes of the mouth and 

 pharynx. The temperature remains up after the appearance of the 

 rash! The rash consists of little red patches about 4 or 5 mm. in 

 diameter which at first disappear on pressure. Like the typhus 

 rash, they become darker red, then purplish and later hemorrhagic 

 in character. Small petechial spots may appear in the center. They 

 fade into pigmented spots later. During recovery desquamation 

 occurs. 



There may be violent nervous symptoms. The blood picture is 

 not altered materially, the leucocytes slightly increase in number, 

 but the differential count remains approximately normal. 



The mortality of the disease as estimated from various sources 

 by Wol bach for 1915 and 1916, ranged between 7 and 13 per cent. 



The incubation time seems to vary between three and nine days. 



45 Wolbach, Jour. Med, Kes., 41, 1919, 1. 



