Tick-Borne Illness Surge: ER Visits Hit Highest Level Since 2017
Weekly emergency room visits for tick bites have reached their highest level since at least 2017, according to new CDC data.
The increase has been observed nationwide, with the Northeast region reporting the highest rates. Medical professionals and health officials have noted several potential contributing factors, including weather patterns and changes in disease reporting criteria.
National and Regional Data
According to CDC data updated in April 2025, the weekly rate of ER visits for tick bites is 71 per 100,000 total visits. This figure is more than double the seasonal average of approximately 30 per 100,000 visits typical for this time of year.
The Northeast region currently reports the highest rate of tick-bite visits. The order of regions by rate is:
- Northeast
- Midwest
- Southeast
- West
- South Central
In the Northeast specifically, data shows 163 tick-related visits per 100,000 ER visits, up from 52 in March. In Wisconsin, the rate for the week ending April 19, 2025, was 44 per 10,000 ER visits, approximately double the rate from the same week in 2024.
"Current levels are well above historic average and even well above last year."
— Dr. John J. Halperin, Atlantic Health Overlook Medical Center
Seasonal Context
The historical peak for ER visits related to tick bites is May. Health officials have stated it is unclear if the current upward trend will continue through the typical peak season.
Medical Professional Statements
Dr. John J. Halperin, chair of the New Jersey Stroke Care Advisory Panel and a member of the department of neuroscience at Atlantic Health Overlook Medical Center, stated that current levels are "well above historic average and even well above last year."
Dr. Halperin noted several factors that may contribute to the data:
- Ticks appear to have started their season earlier.
- There appears to be a greater number of ticks.
- A change in CDC criteria for confirming Lyme disease cases has led to an increase in reported numbers.
- It is not entirely clear how much of the increase in ER visits is due to increased public awareness versus an actual increase in tick populations.
- He stated it is possible the monthly average for April will level out to match prior years.
Dr. Christopher Bazzoli, an emergency medicine physician at Cleveland Clinic, stated that increased tick populations, warmer weather, and heavy rains could lead to some tick populations growing earlier in the season. He noted that ticks tend to become active when temperatures reach 45 degrees Fahrenheit or more.
Long-Term Trends
Tick-borne diseases have been increasing in recent years. Some scientists suspect this trend is partly linked to climate change, which has been associated with shorter winters, earlier springs, and hotter summers. Researchers also attribute the rise to growing deer populations and suburban development.
Spring and early summer are considered prime time for bites from the youngest form of ticks, which are responsible for most bites on humans.
Tick-Borne Diseases
According to the CDC, ticks are responsible for 90 percent of all vector-borne diseases in the United States. Diseases carried by ticks include:
- Lyme disease: Typical in the Northeast, Mid-Atlantic, and Midwest
- Rocky Mountain spotted fever: Found nationwide
- Anaplasmosis and ehrlichiosis: Common in eastern and southern U.S.
- Powassan virus: Common in the Northeast and Great Lakes region; 76 Americans were diagnosed with Powassan virus in 2025, a record annual count
- Babesiosis: Primarily found in the Northeast and upper Midwest
- Alpha-gal syndrome: Carried by the Lone Star tick; causes an allergic reaction to meat and dairy
In 2024, Wisconsin recorded 6,469 Lyme disease cases, with cases quadrupling over the past 20 years.
Prevention Recommendations
The CDC and medical professionals recommend the following measures:
Outdoor Activity Precautions
- Know where ticks live (grassy, brushy, or wooded areas, including backyards)
- Avoid high-risk areas such as tall grass, leaf litter, and dense brush
- Walk in the center of trails
Protective Clothing and Gear
- Wear long sleeves and pants to reduce exposed skin
- Wear light-colored clothing to make ticks easier to see
- Treat clothing, boots, and camping gear with products containing 0.5 percent permethrin, or buy pre-treated items
- Use EPA-registered insect repellents with ingredients like DEET, picaridin, or oil of lemon eucalyptus; avoid use for children under age 3
Post-Outdoor Activity Checks
- Check clothes after being outside and tumble dry on high heat to kill hidden ticks
- Shower within two hours of coming inside
- Perform a full-body tick check, paying attention to hidden spots
- Check pets for ticks, including between toes
Tick Removal
If a tick is found, use fine-tip tweezers to grasp it as close to the skin's surface as possible.
- Pull upward with steady, even pressure
- Clean the bite area after removal
- Take a picture of the tick to aid in identification