Rocky Mountain spotted fever (RMSF) is rare in Michigan. While national spotted fever rickettsiosis reports have grown since 2000, this trend stems from broader, less-specific testing, not a rise in confirmed RMSF.
On paper, it looks like Rocky Mountain spotted fever is becoming more common. It’s reasonable to worry about. That said, the answer is not a simple “yes, it’s becoming more common.” To say it is buries the fact that the real picture is a bit more complicated.
Reported spotted fever rickettsiosis cases rose from under two per million in 2000 to thirteen per million in the mid-2010s. However, this statistic is easy to misinterpret. The case definition accepts nonspecific lab evidence, and strict reviews confirm just 1% of these reports. Expanded testing, not a true rise in Rocky Mountain spotted fever, drives this increase.
Also important is geography. RMSF has been concentrated in specific regions in the Southeast and south-central states. Just five (North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri) account for the majority of cases. It’s carried mainly by the American dog tick, along with the brown dog tick and Rocky Mountain wood tick, which are different from the blacklegged deer tick that spreads Lyme disease.
For Michigan specifically, RMSF is present but uncommon. The dog ticks that can carry it do occur here, so the risk isn't zero, but Lyme disease and anaplasmosis are the far bigger tick-borne concerns in this state. No matter what, though, good tick prevention helps reduce your odds of catching any of these diseases in the first place.
If you're tired of sorting out which tick-borne illnesses to worry about, Mosquito Squad of Metro Detroit can help. Mosquito Squad can help you to reduce the ticks behind all of them. This can help you protect your family with up to 90% reduction in pest activity on a recurring 21-day cycle.
