Ticks in Wisconsin: What You Need to Know
Ticks are commonly found in many areas of Wisconsin and can spread diseases to people and animals by biting them. Ticks feed on blood by attaching their mouth parts into the skin of a human or animal. During feeding, ticks release saliva that may contain germs.
After you, your family members, or your pets spend time in the woods or areas with tall grass or brush, it is always important to check for ticks, especially in the spring, summer, and early fall. Learn more about ticks.
Tick ID service
Have you recently found or removed a tick from yourself, your child, or your pet and want to learn more about it? The Wisconsin Department of Health Services offers a fast and simple Tick Identification Service based on a few questions and photographs you submit online. You can send a submission if you live in Iowa, Illinois, Michigan, Minnesota, and Wisconsin.
Important note: The Tick Identification Service cannot determine if the tick you found was carrying any germs or whether it made you sick. If you were bitten by a tick, or think you may have been bitten, monitor yourself for rash, fever, new muscle and joint pain, and new fatigue for 30 days. If any of these symptoms occur, contact your health care provider immediately. The only way to know if a tick made you sick is through an evaluation, and sometimes a blood test, performed by a health care provider. If you were bitten by a tick and live in Wisconsin where Lyme disease is common, consider contacting a health care provider right away to see if a single dose of antibiotics may be appropriate to help prevent Lyme disease.
Submit an image of a tick for identification
Wisconsin tick bite tracker
The Wisconsin Department of Health Services monitors emergency department (ED) data for people seeking medical care for tick bite-related concerns throughout Wisconsin. Looking at trends in tick bite-related ED visits helps people see when they are likely to be at higher risk for tick bites. The interactive tick bite tracker allows you to view statewide and regional trends in tick bite-related ED visits and compare data for the past five years. Ticks are most active in Wisconsin from spring through fall, but you should use caution throughout the year.
Additional tick bite data in Wisconsin
Data are also available in the accordion below to compare the rate of tick bite-associated ED visits by public health region.
Compare the rate of tick bite-associated emergency department (ED) visits per 10,000 ED visits by public health region
Data shown are subject to change and may be updated as more information is available.
Past trends in ED visits for tick bites during the year have corresponded closely with what we know about the tick life cycle. For example, when tick bite-related ED visits begin to increase in the spring, it typically corresponds with our observance of adult ticks becoming more active in the environment. The spring increase then moves into the summer peak which corresponds with when we typically see the emergence of nymphal stage ticks.
How to use the data visualizations
The two visualizations on this page are interactive and provide the rate of tick-associated visits per 10,000 ED visits by week.
The first visual includes data for tick-associated ED visits for 2024 and 2025. You can add additional years’ data for 2021, 2022 or 2023 by clicking the check boxes. You can also use the dropdown menu to filter and view data for one of the five Wisconsin public health regions.
The second visual allows the user to examine patterns of disease activity across Wisconsin public health regions by week for the previous year.
Technical data notes and data sources
Data source: ESSENCE (Electronic Surveillance System for Early Notification of Community Based Epidemics) from the National Syndromic Surveillance Program.
Approximately 95% of non-federal Wisconsin EDs are represented in the dataset, and most EDs transmit visit information into ESSENCE within 24 hours.
Combinations of specific words and ICD diagnostic codes are typically used to identify emergency department visits by patients with specific concerns. However, there is not an ICD code for “tick bite,” so we were not able to use ICD codes to detect these visits. Instead, records containing the various spellings of the word “tick” or the combination of the “tick” and “bite” are located and counted
Weekly rate of tick bite-associated ED visits are calculated by adding the number of visits to the ED with a diagnosis meeting the above definition during a week (Monday through Sunday) and then dividing that number by the total number of visits to the ED for the same week. This value is multiplied by 10,000 to express the value as a rate per 10,000 visits.
About ticks
Ticks are arachnids, related to spiders, mites, and scorpions. In Wisconsin, there are three types of ticks that can spread disease to people:
- The deer (blacklegged) tick
- The wood (American dog) tick, and
- The lone star tick.
Nearly all illnesses spread by ticks in Wisconsin are caused by the deer (blacklegged) tick. Most people who get sick from a tick bite will do so in the late spring, summer, or early fall, when ticks are most active, and people are outdoors.
There are four different stages in a tick life cycle.
This cycle includes egg, larva, nymph, and adult stages. Once they hatch from eggs, ticks need to have a blood meal to develop into the next life stage.
Ticks feed by biting and attaching to the skin of an animal or person, called a host. When a tick attaches to a host, it will usually feed for three to seven days.
It is during the first blood meal, commonly taken from a small mammal, such as a mouse, that a tick may become infected with a bacteria, parasite, or virus.
An infected tick that then goes on to bite a person can potentially spread any germs it may be carrying.
Usually, only nymphs and adult female ticks can spread illnesses.
Ticks live in wooded areas and areas with tall grass or brush. They do not jump or fly and usually stay close to the ground to find a host to attach themselves to. Ticks find a host by crawling to the edge of a leaf or blade of grass and wait for an animal or person to brush up against them. They then bite and attach to the host for a blood meal.
A warmer and wetter climate can increase the risk of getting an illness from a tick. This is because ticks thrive in warm, humid weather. Warming temperatures in Wisconsin have created favorable conditions for ticks to survive in more areas of the state and have made the active tick season longer. For more information, visit our Climate and Infectious Disease page.
Ticks must bite you to spread their germs. The chance that a tick will spread a germ to you increases the longer it remains attached. This means that checking for ticks regularly and removing a tick quickly can help reduce your chance of infection.
For most germs spread by ticks in Wisconsin the tick must remain attached for at least 24 hours, but this varies by disease. To spread Lyme disease, a tick usually must remain attached for at least 24 to 36 hours. To spread anaplasmosis, a tick usually must remain attached for at least 12 to 24 hours. To spread Powassan virus, a tick likely only needs to be attached for less than 12 hours and may spread in as little as 15 minutes.
The best way to avoid getting sick from a tick is to prevent them from biting you. There are many ways to prevent tick bites when spending time where ticks may live, including doing daily tick checks, showering within two hours after being outdoors, using insect repellent, and wearing long sleeves and pants to prevent ticks from getting on you.
Check out other tips to prevent tick bites!
If you remove a tick from your body, testing the tick for any diseases is typically not recommended for multiple reasons:
- Tick testing laboratories may have lower standards than clinical diagnostic laboratories.
- If your tick tests positive for a disease, it does not necessarily mean you were infected.
- If your tick tests negative for a disease, it does not rule out infection from other ticks you may have been bitten by.
- If you have been infected, you will likely develop symptoms and require treatment before getting your tick testing results back.
However, if you are curious to want to know what type of tick bit you, the Wisconsin Department of Health Services offers the ability to submit an image of a tick for identification by the Tick Identification Service. Different types of ticks live in different parts of the country and the state. There are over 15 types of ticks in Wisconsin alone, however, most human tick bites in Wisconsin are from deer ticks or wood ticks.
Tick bites can be unpleasant and can sometimes cause an illness, however, most people do not need to see a doctor immediately after being bitten by a tick. Taking antibiotics is usually not recommended to prevent illnesses caused by ticks after being bitten, but it can be helpful in some circumstances. How do you know if you should see a doctor to talk about taking a dose of an antibiotic to prevent Lyme disease? The CDC's (Centers for Disease Control and Prevention) Tick Bite Bot is an interactive tool that can help you determine if you should see a doctor.
Whether or not you see a doctor immediately after a tick bite, you should monitor for symptoms for at least 30 days after removing the tick. Call your health care provider right away if you develop any of the following symptoms within 30 days after being bitten:
- Rash
- Fever
- New or worsening fatigue
- New or worsening muscle pain
- Joint swelling and pain
The best way to avoid getting sick is to prevent tick bites.