April 4, 2012
Early spring leads to an early start to the tick-borne disease season
Minnesota residents should start protecting themselves from ticks now, health officials advise
Minnesota’s unusual stretch of warm weather in late winter and early spring has led to earlier than normal tick activity and a sudden start to the tick-borne disease season. Health officials urge Minnesotans to begin their efforts to protect themselves from ticks and the diseases they carry.
Early melting of Minnesota’s already limited snow cover this winter coupled with recent warm temperatures have allowed blacklegged ticks, often called the "deer ticks," to feed across the forested regions of Minnesota. This type of tick carries the agents of several diseases, including Lyme disease, human anaplasmosis, babesiosis, Powassan disease, and a new form of human ehrlichiosis. Over the last decade, 1,000 to 2,000 or more combined cases of these tick-borne diseases each year have been reported to the Minnesota Department of Health, with these numbers increasing in recent years.
The risk for diseases from blacklegged ticks in Minnesota usually starts to rise in late spring and stays elevated until mid-summer, with a smaller peak again in autumn. “Unfortunately, a mild winter and warm March weather this year hastened the beginning of the season for tick exposure,” said Dave Neitzel, an MDH epidemiologist specializing in tick-borne diseases. “This early start to the tick season could lead to a longer than usual risk season in 2012, potentially worsening Minnesota’s troubling trend of marked increases in numbers of Lyme disease and other tick-borne disease cases.”
Blacklegged ticks carry most of Minnesota’s tick-borne diseases. In addition, American dog ticks (“wood ticks”), which are very common in spring and early summer throughout Minnesota, can carry Rocky Mountain spotted fever (RMSF). While RMSF is most common in the southern United States, a small number of RMSF cases, including one death, have occurred in Minnesotans who did not travel outside the state.
The best way to prevent tick bites is to avoid tick habitat during warm weather months:
- Wooded or brushy areas for the blacklegged tick
- Grassy or wooded areas for the American dog tick
If you can’t avoid tick habitat, use repellent to reduce the risk of disease:
- DEET-based repellents (up to 30 percent DEET), which can be applied to clothing or skin for temporary protection
- Permethrin-based repellents, which are used to pre-treat fabric and can protect against tick bites for at least two weeks without reapplication
People who live on heavily wooded property, whether permanent homes or cabins, often encounter ticks on a daily basis. Since daily repellent use can be more challenging for these people, they should consider the following landscape management techniques:
- To make your yard less attractive to ticks:
- Keep lawns mowed short
- Remove leaves and brush
- Create a landscape barrier of wood chips or rocks between mowed lawns and woods
- To reduce tick numbers at your yard-woods interface:
- Apply pesticide treatments in the spring or early summer along the edges of wooded yards and trails; follow pesticide label instructions carefully.
- Follow details on personal protection and landscape management to reduce tick-borne disease risk available at: http://www.health.state.mn.us/divs/idepc/dtopics/tickborne/prevention.html.
Early detection of tick-borne illness is important to prevent severe complications, so people should seek medical care if they develop an illness suggestive of a tick-borne disease after spending time in tick habitat. Signs and symptoms of the various tick-borne diseases can include, but are not limited to, rash, fever, headache, fatigue, muscle aches, joint pain or swelling, and facial droop. These symptoms can also be involved in other diseases, so it is important for a patient's medical provider to consider tick-borne and non-tick-borne causes. Fatal cases of tick-borne disease occur each year in Minnesota residents. Except for Powassan disease, which is caused by a virus, all of Minnesota's tick-borne diseases are treatable with antibiotics.
More information about Minnesota's tick-borne diseases, including signs, symptoms, and prevention, is available on the MDH website (http://www.health.state.mn.us/divs/idepc/dtopics/tickborne/index.html) or by calling MDH at 651-201-5414.