Between 2002 and 2004, 15 cases of Rocky Mountain spotted fever (RMSF) were reported in an Arizona community where the disease was previously unknown.
The outbreak was linked to the brown dog tick, which had not been recognized as a RMSF transmitter in the U.S. before.
Serologic tests showed increased exposure to RMSF among local children (10%) and dogs (70%), compared to lower rates (5%) from samples taken in 1996, indicating that RMSF may now be endemic in the area.