Unseasonably warm weather this past winter and an early spring has set the stage for a large crop of ticks this year in Wisconsin, according to public health officials, who are urging precautions to reduce the likelihood of bites from the disease-carrying arachnids.
"Ticks and other pests will be out in full force this spring and summer," said Jim Fredericks, chief entomologist and vice president of technical and regulatory affairs for the National Pest Management Association. "With growing concern over infectious diseases, diligent prevention and awareness are especially necessary given the high pest populations that are projected for the warmer seasons ahead."
The "bug barometer" forecast published April 3 by the National Pest Management Association expects this year's weather to give tick populations an early boost in the Midwest.
The most common tick-borne illness in Wisconsin is Lyme disease, but ticks also carry anaplasmosis, babesiosis, ehrlichiosis, powassan virus infection and spotted fever rickettsiosis (including Rocky Mountain spotted fever and typhus fever).
Lyme disease is increasing in Wisconsin, according to the Wisconsin Department of Health Services. The state is in the top 25% of those reporting high incidence of the disease.
The disease is acquired through the bite of a blacklegged tick (commonly known as the deer tick) infected with the bacterium Borrelia burgdorferi.
In 2015, there were 3,267 cases of Lyme disease reported in Wisconsin, the fourth-highest total since 1990, according to state health officials.
Nationally, the Centers for Disease Control and Prevention estimates the total number of Lyme disease cases is approximately 10 times higher than what is reported.
Similar to the national number, the actual number of Lyme disease cases in Wisconsin is likely much greater because of incomplete testing, misdiagnoses and underreporting, according to a 2016 report from the Wisconsin Environmental Public Health Tracking Program.
Lyme disease has been reported in every county in Wisconsin, with the highest incidence in the northwest part of the state.
Wisconsin has experienced a warmer and wetter climate in recent decades and this increased humidity and temperature create a hospitable environment for ticks, according to the Wisconsin Department of Health Services.
The risk of tick exposure occurs when it is warm enough for ticks to be active, usually from spring to autumn. But ticks may be active whenever the temperature is mild, typically 40 degrees or above.
The majority of reported Lyme disease cases occur between May and August.
The North Dakota Department of Health offers the following tips to help reduce the chance of a tick bite:
Use Environmental Protection Agency (EPA)-registered insect repellent, including those with at least 20% DEET.
Use products that contain permethrin on clothing and gear such as boots, backpacks and tents.
If possible, avoid walking through brushy areas, high grass and other sites prone to harbor ticks.
Wear light-colored clothing to make the ticks easier to see.
Wear long pants and tuck the legs into your socks or boots.
Keep your shirt tucked in.
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.
Carefully examine gear and pets for ticks.
Place clothes in a dryer on high heat for 10 minutes to kill ticks on dry clothing after you come indoors.
If a tick becomes embedded in skin, remove it promptly. Use a tweezers to pull the tick up and out from the body then disinfect the site and wash hands.
If a tick is attached for greater than 24 hours, the Wisconsin Department of Health Services recommends consulting a doctor for a single dose of doxycycline to prevent Lyme disease.