The Typhus-Rocky Mountain Spotted Fever Group in the United States

Epidemic typhus fever has been a scourge in Europe for many centuries. First differentiated from typhoid by Gerhard¹in Philadelphia in 1837, epidemic typhus has been introduced into our Eastern seaports from time to time in connection with immigration. Tabardillo, or Mexican typhus, has been present in the highlands of Mexico for many years. The disease may possibly have been introduced into Mexico at the time of the Spanish Conquest or, as Mooser²suggests, it may have been present in Mexico prior to the conquest. Tabardillo has been introduced across our Mexican border from time to time in much the same way that European epidemic typhus has been brought to our seaports. Brill's disease was described in this country by Dr. Nathan E. Brill, in 1910.³Subsequent researches by Anderson and Goldberger⁴identified this disease, immunologically, with Mexican typhus. In more recent years, largely through the