Health officials are monitoring a significant rise in tick encounters. According to the U.S. Centers for Disease Control and Prevention (CDC), emergency room visits for tick bites nationwide are currently at their highest weekly rate for this time of year since 2017. This pattern is being observed across multiple regions. In the Midwest, which the CDC’s Tick Bite Data Tracker identifies as ranking second among U.S. regions for the highest rate of tick-related doctor and ER visits so far in 2026, health systems are already seeing the impact of an early season.
In Wisconsin, the trend is particularly acute. Data from the state Department of Health Services (DHS) for the week ending April 19 shows a rate of 44 tick-bite visits for every 10,000 emergency room visits. Xia Lee, a DHS public health entomologist, noted that this figure is about double
the number of ER visits for tick bites recorded at this time last year. This increase in clinical encounters indicates that the risk window for tick exposure has moved forward into the early spring.
Warm snaps and the biology of early emergence
From a public health perspective, the timing of tick emergence is closely tied to environmental triggers. Ticks are highly sensitive to temperature and humidity, and recent weather patterns have created an ideal environment for their activity. According to the DHS, warmer and wetter weather increases the risk of illness because ticks thrive in warm, humid conditions.
This year, that threshold was met early. In Wisconsin, February was almost 6 degrees warmer than usual, and the state is experiencing its wettest April on record. These conditions have prompted wood ticks, in particular, to emerge about two weeks earlier than normal, according to Xia Lee. Researchers found that this early arrival can create a compounding effect where new ticks enter the environment while deer ticks from previous cycles are already active.
“Compounded with the deer ticks already out there, what we’re seeing is just this large spike in the number of (emergency department) visits because there are more ticks out there a lot earlier,” Xia Lee, DHS public health entomologist
The driver behind this shift is often linked to the increase in frost-free days. Andrew Lewandowski, a pediatrician and board member for Healthy Climate Wisconsin, explains that warming weather is expanding the timeframe in which ticks can remain active and spread disease. Even in regions that experienced a harsh, snowy winter, the assumption that cold weather suppresses tick populations is a misconception. Julie McCarthy, the town of Needham’s assistant public health director for nursing and behavioral health, points out that ticks are really hardy
and utilize burrows, bushes, and long grass to hide until temperatures rise.
The rising clinical burden of Lyme disease
The surge in tick encounters naturally leads to a higher risk of tick-borne illnesses, with Lyme disease being the primary concern during the spring. Dr. Greg Demuri, a professor of pediatric infectious diseases at the University of Wisconsin School of Medicine and Public Health, identifies spring as the most dangerous season for these infections.
“I think it’s going to be a big year for Lyme,” Dr. Greg Demuri, University of Wisconsin School of Medicine and Public Health
The long-term trajectory for Lyme disease is already upward. Wisconsin recorded a record 6,469 cases of Lyme disease in 2024, and the total number of cases has quadrupled over the past 20 years. While some of this increase is attributed to better reporting and a higher desire for testing, the geographic spread of the ticks is a contributing factor. PJ Liesch, an extension entomologist at UW-Madison, reports that ticks have spread from the northwestern woods of Wisconsin to nearly every part of the state.
The risk of infection depends heavily on the type and age of the tick. According to Liesch, an average of 20 percent of juvenile deer ticks and 40 percent of adult deer ticks are positive for Lyme disease. This means that nearly half of the adult population in some areas can transmit the bacteria, making early detection and prevention critical for patient outcomes.
Practical prevention for humans and pets
Preventing a tick bite is the only definitive way to avoid the subsequent clinical complications of Lyme disease. Because most people do not feel a tick bite when it occurs, the focus must be on physical barriers and chemical repellents. Health experts, including those cited by NBC Boston, recommend wearing long sleeves and pants when spending time in brush, wooded areas, or tall grass.
The use of EPA-registered repellents containing DEET is another essential layer of protection. While many people associate DEET primarily with mosquitoes and flies, Julie McCarthy emphasizes that it is an important part of tick prevention
. In addition to personal protection, homeowners can reduce the tick load on their property by keeping grass mowed short and cutting back bushes, as these areas serve as primary hiding spots for ticks.
Pet owners face a secondary risk: the role of animals as vectors. Sharon Woo, a dog owner in Jamaica Plain, noted that she has seen more ticks on her dogs this year, which serves as a reminder that pets can carry ticks into the home and eventually transfer them to their owners.
“First thing when tick season starts, I’m more worried about my dogs,” Sharon Woo, dog owner
Some pet owners utilize preventative measures such as vaccinations and regular tick checks to manage the risks associated with pets bringing ticks into the household environment.
What to watch for as the season peaks
While ER visits are spiking now, the full impact of the season will not be clear immediately. State health officials in Wisconsin expect Lyme disease cases to typically peak around June. Because of this timing, officials noted that they will not know if it is a particularly bad year for the disease until that peak is reached.
For those who have spent time outdoors, the priority is a thorough tick check on both themselves and their pets. Because the bite is often painless, visual inspection is the most reliable method of detection. If a tick is found, prompt removal is necessary.
Patients should monitor their health closely in the weeks following a suspected encounter. According to <a href="https://valleynewslive.
- Fever
- Rash (particularly the characteristic “bullseye” rash associated with Lyme)
- Joint pain
Early intervention is key to preventing the long-term joint and neurological complications associated with tick-borne According to state health officials, this monitoring is essential to ensure that any potential case of the disease is detected as quickly as possible.
