RMSF is a tick borne febrile illness most commonly characterized by acute onset and usually accompanied by malaise, myalgia, headache, nausea, and petechial rash. This rash is present in 2/3 of cases and appears as small red spots or blotches that begin on the wrist, ankles, palms, and soles. It spreads up the arms and legs toward the trunk. It is the most prevalent rickettsial disease in the U.S. In Michigan, most RMSF cases have been reported from the lower half of the Lower Peninsula. Additionally, cases are regularly reported from northwestern Ohio and northern Indiana. RMSF is caused by tiny, roundish bacteria called Rickettsia rickettsii, which are transmitted through the bite of a tick. Several tick vectors may be involved in RMSF transmission, but the primary one in Michigan is the American Dog tick, Dermacentor variabilis. This tick is the most common tick in the state and is found throughout Michigan.

Symptoms:
Symptoms begin 3-12 days after tick exposure. Once symptoms develop, death can occur within two weeks without proper treatment. At the time of initial presentation, the classic triad of RMSF, fever, rash and history of tick bite, is often present.

Other Characteristics: Malaise Severe headache Chills and Myalgia
	Hand with petechial rash

Wildlife and Companion Animals

Various wildlife species serve as hosts of the RMSF rickettsial organism and the ticks themselves: deer, fox, wolf, badger, opossum, rabbit, raccoon, skunk, squirrel, deer mice, and chipmunks. RMSF disease has not been diagnosed in any of these wildlife species.

Dogs are very susceptible to RMSF. Other small domestic mammals that are allowed outdoors or have contact with infected ticks may also contract this disease. Signs of RMSF include combinations of fever, lack of appetite, arthritis, shortness of breath, coughing, abdominal pain, nervous system disorders and swelling of the face or extremities. Small hemorrhages on the mucous membranes occur in severe cases. Transmission from dogs to humans does not occur, but people should exercise caution when removing ticks from pets, as the fluids from the tick can carry the RMSF organism.