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April 15, 1950


JAMA. 1950;142(15):1217-1218. doi:10.1001/jama.1950.02910330099016

The chief vectors for the transmission to man of Rocky Mountain spotted fever are the wood tick and the American dog tick. The former is found throughout the Rocky Mountain region and adjacent areas and the latter on the great plains and eastward to the Atlantic coast, to the South reaching into Mexico, and in Canada, eastward from southern Manitoba to Labrador. The wood tick becomes active during the spring and early summer. The dog tick appears in late spring and remains active longer during the summer. In a recent study, Harrell1 points out that ticks hang from the lower branches of small bushes and shrubs, waving their legs, and thus transfer easily to the hair of passing warm-blooded animals.

Rocky Mountain spotted fever is a severe rickettsial disease, which occurs when a human being is bitten by an infected tick. The rickettsias are found in the blood early