In the western U.S., the
causative agent R rickettsii is transmitted by the wood tick, and
in the eastern U.S., by the dog tick. Other ticks transmit the
infection in the southern U.S. and in Central and South America.
Contrary to the name "Rocky Mountain" most recent cases
have been reported in the eastern United States: North and South
Carolina, Virginia, Maryland, Georgia, Tennessee, and Oklahoma.
Most cases occur in the spring and summer with about 1,000 cases
reported per year. Most of the reported cases have been in