7 things to know about ticks in Wisconsin

PJ Liesch

Interestingly, deer ticks are relatively new to the upper Midwest and were not spotted in Wisconsin until the late 1960s. Fast forward 50 years, and these ticks can be found in nearly every corner of the state.

Spring not only means getting out into fields and enjoying barbecues, but it also means increased tick activity. Ticks can affect humans and animals alike and due to disease concerns with some of the tick species, they aren’t something to ignore. Below are seven things that Wisconsinites should know about ticks:

1. Over a dozen species of ticks have been documented in Wisconsin. While this sounds like a lot, most Wisconsinites will only ever bump into a few of these species. The commonest two are deer ticks (aka “blacklegged ticks”) and wood ticks (aka “American dog ticks”). Many of the other tick species are “specialists” associated with specific wild animal hosts and are unlikely to be encountered.

2. The deer tick is our tick species of greatest health concern. Deer ticks are notorious for their association with Lyme disease, but they can also carry other diseases including anaplasmosis, babesiosis, Powassan virus, and more. At the moment, roughly 20% of juvenile deer ticks (nymphs) and 40% of adult deer ticks in Wisconsin are carrying Lyme. In recent years, there have been approximately 3,000 Lyme disease cases estimated in WI each year, although the CDC estimates that the actual total might be 10x higher. These diseases can pose serious health threats, so prevention should be taken seriously.

3. The lone star tick is relatively new and rare, but is a growing concern. Lone star ticks are primarily found to the south and east of us but we’ve been seeing more reports in Wisconsin over the last decade. Not only can this tick spread diseases such as ehrlichiosis, but its saliva can cause you to develop an allergic reaction to red meat. This sounds weird, but is not something you want to deal with if you enjoy a good burger, brat, or steak on the grill.

While over a dozen tick species have been identified in Wisconsin, the commonest two are deer ticks (aka “blacklegged ticks”) and wood ticks (aka “American dog ticks”).

4. Simple precautions can help prevent tick bites. One of the easiest precautions is to wear long sleeved clothing to act as a physical barrier between ticks and your skin. Repellents are another excellent precaution—DEET, picaridin, IR3535, and oil of lemon eucalyptus have all been shown to effectively repel ticks. If you work or recreate in areas with high tick activity, there are also specific clothing treatments containing permethrin that repel and kill ticks. Such products can be found at most outing goods stores and can last through many washings—really helpful if you spend time out in a tree stand or hunting blind.

5. Don’t forget about tick checks. Checking for ticks isn’t just a line from Country music. Tick checks can be an extremely helpful approach to prevent transmission of Lyme disease. If a deer tick infected with Lyme bites a human, transmission of the disease doesn't occur immediately. Rather, it takes about a day and a half or longer for transmission—the longer the tick is attached, the higher the risk. Thus, checking for and removing ticks daily can be a helpful precaution.

6. Don’t forget Fido. Just like humans, pets can get diseases such as Lyme disease from ticks. Chat with your veterinarian about appropriate treatments for companion animals that spend time outdoors and don’t forget about tick checks for pets as well.

7. The Asian longhorned tick isn’t in Wisconsin yet, but is a concern for agriculture in the state. The Asian longhorned tick is a new invasive tick species first reported in the US in 2017. Currently, it’s mostly known from the mid-Atlantic states, but has been spotted in parts of Kentucky and Missouri. This tick can pose serious concerns for livestock as it can occur in very large numbers (thousands of ticks) and can cause stress, reduced growth, and severe blood loss. Furthermore, female longhorned ticks can reproduce without males, meaning that a single introduced female tick has the potential to start a new population. If you encounter unusually large numbers of ticks on livestock, contact your local Extension office or the UW Insect Diagnostic Lab (insectlab.russell.wisc.edu) to get the ticks properly identified.

Liesch is the University of Wisconsin Extension Entomologist & Director of the UW Insect Diagnostic Lab

Extension University of Wisconsin-Madison