Bites from blacklegged ticks (also called deer ticks) led to a record number of tick-borne disease cases in Minnesota during 2007, say state health officials. Blacklegged ticks carry Lyme disease, human anaplasmosis, and babesiosis, three illnesses which can all lead to serious complications.

To prevent these diseases, it is critical for people who spend time outdoors in many areas of east-central, north-central, and southeast Minnesota to take precautions against tick bites. “Minnesota continues to be one of the highest-risk states for diseases from blacklegged ticks,” said Melissa Kemperman, an epidemiologist at the Minnesota Department of Health (MDH). “If you visit or live in forested parts of Minnesota during late spring and early summer, you must protect yourself from tick bites to avoid developing Lyme disease or other tick-borne illnesses.”

Record tick-borne disease numbers suggest that many Minnesotans aren’t taking the simple steps necessary to protect themselves from tick bites. In 2007, record totals of 1,239 Lyme disease cases, 322 human anaplasmosis cases, and 24 babesiosis cases were reported to MDH. These numbers were greater than the previous records of 1,023 Lyme disease cases reported in 2004, 186 human anaplasmosis cases reported in 2005, and 18 babesiosis cases reported in 2006.

Precautions are most important during the late spring, early summer, and fall, when blacklegged ticks are active. “It is important to check yourself for ticks, but these ticks are so difficult to see that you should also strive to prevent bites in the first place,” says Kemperman. “When spending time in wooded or brushy areas, it is crucial to use tick repellents containing DEET or permethrin. Also, wear long pants and light-colored clothing and stay to the center of trails. Keep these steps in mind when hiking, camping, biking, hunting, working, or doing other activities in forested areas.”

Repellents containing up to 30% DEET can be used on the skin or clothing. Permethrin-based products, which are applied to clothing only, are highly effective and can last through several washings. Since ticks climb up from the ground, focus repellent use below the knees.

Minnesotans who live in or near the woods can also be exposed to blacklegged ticks during yardwork or other outdoor activities at home. Maintaining a yard free of brush and leaves, constructing a wood chip barrier between the lawn and woods and keeping children’s play areas in sunny areas of the yard will help limit exposure to disease-carrying ticks. Under certain conditions, using a carefully applied pesticide targeted towards ticks may also help reduce tick numbers in wooded yards

The prime season for tick-borne disease begins in May.