The Michigan Department of Health and Human Services (MDHHS) has confirmed a case of Rocky Mountain spotted fever (RMSF) in a child in Cass County. This is the first confirmed case of RMSF contracted in Michigan since 2009.

Dermacentor variabilis Image/CDC
Dermacentor variabilis
Image/CDC

RMSF is a tick-borne disease caused by the bacterium Rickettsia rickettsii, and can be fatal if not treated promptly and correctly, even in previously healthy people. Symptoms typically include fever, abdominal pain, vomiting and muscle pain. A characteristic rash may develop a few days later. The rash typically consists of small, flat, pink, non-itchy spots on the wrists, forearms, and ankles that spreads to include the trunk, and sometimes the palms of the hands and soles of the feet.  However, some people never develop the rash, or the rash may have an atypical appearance.

“Like all tick-borne illnesses, the best way to protect yourself against Rocky Mountain spotted fever is to prevent tick bites,” said Dr. Eden Wells, chief medical executive of the MDHHS. “Let your doctor know right away if you develop signs of illness such as fever, rash, or body aches in the days after a tick bite or potential exposure. Early detection and treatment are essential to preventing serious health complications.”

RMSF can be challenging to diagnose because it can mimic other common diseases.  Early treatment is essential to preventing serious complications, including death. If RMSF if suspected, the antibiotic doxycycline is the first line treatment for both adults and children, and should be initiated immediately.

There are a number of ticks in the United States that can transmit RMSF including the American dog tick, Dermacentor variabilis, which is the most common tick encountered in Michigan. Other ticks that transmit the disease outside of Michigan are the Rocky Mountain wood tick, Dermacentor andersoni, and the brown dog tick, Rhipecephalus sanguineus.

Residents can protect themselves by using the following tips to prevent tick bites:

  • Avoiding tick-infested areas.  This is especially important in the spring and summer in Michigan. If you are in tick infested areas, walk in the center of trails to avoid contact with overgrown grass, brush, and leaf litter at trail edges. Dogs and cats can come into contact with ticks outdoors and bring them into the home, so using tick prevention products on pets is recommended.
  • Using insect repellent. Apply repellent containing DEET (20-30 percent) or Picaridin on exposed skin. You can also treat clothes (especially pants, socks, and shoes) with permethrin, which kills ticks on contact or buy clothes that are pre-treated. Permethrin can also be used on tents and some camping gear. Do not use permethrin directly on skin. Always follow the manufacturer’s instructions when applying any repellents.
  • Bathing or showering.  Bathe or shower as soon as possible after coming indoors (preferably within two hours) to wash off and more easily find ticks that are crawling on you. Ticks can get a ride indoors on your clothes. After being outdoors, dry clothing should be tumble dried in a dryer on high heat for 10 minutes to kill ticks.  If the clothes are damp, additional time may be needed.  If the clothes require washing first, hot water is recommended. The clothes should be warm and completely dry when finished.
  • Performing daily tick checks.  Always check for ticks on yourself and your animals after being outdoors, even in your own yard. Inspect all body surfaces carefully, and remove attached ticks with tweezers. Grasp the tick firmly and as closely to the skin as possible. With a steady motion, pull the tick’s body away from the skin. Do not be alarmed if the tick’s mouthparts remain in the skin. Cleanse the area with an antiseptic.

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