Federal health data suggest 2026 could mark the most severe tick season in nearly ten years, with emergency departments nationwide seeing an unusual surge in visits related to tick bites.

Experts warn that the combination of mild winters, expanding tick habitats and thriving wildlife populations may make this year particularly active.

The Centers for Disease Control and Prevention’s Tick Bite Data Tracker shows tick‑bite ER visits running above historical averages across nearly every U.S. region except the South Central states. The Northeast is leading with the highest levels so far this year.

During the fourth week of April, roughly 114 out of every 100,000 emergency visits nationwide involved tick bites, the CDC reported. That rate is the highest for this point in the year since at least 2017.

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Overall, the agency estimates about 31 million Americans are bitten by ticks each year, with approximately 476,000 receiving treatment for Lyme disease, the country’s most common tick‑borne illness.

“Tick season is here and these tiny biters can make you seriously sick,” said Dr. Alison Hinckley, epidemiologist and Lyme disease expert at the CDC’s Division of Vector‑Borne Diseases. “Now is the time for people to take steps to protect themselves and their loved ones.”

Hinckley noted that higher emergency room visits reflect a number of factors including weather patterns and tick population expansion rather than an absolute count of ticks. She emphasized that the overall ranking of 2026 will only be clear once the full season concludes.

Experts say the boundaries of tick season have shifted. Once limited mainly to the hottest months, ticks are now active for longer stretches of the year. Dr. Jim Fredericks, chief entomologist for the National Pest Management Association, attributes this to milder winters and shortened shoulder seasons between winter and summer.

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“These conditions let a greater proportion of tick populations survive the winter, even in places where there has been snow cover,” Fredericks said.

Warmer temperatures arriving earlier and lasting longer have enabled ticks and other pests to thrive. Snow, which was long thought to kill ticks, can in fact serve as an insulating layer, said Dr. Kathryn Reif, associate professor of parasitology at Auburn University’s College of Veterinary Medicine. “Ticks actually do better when there’s more snow rather than less snow because a snowpack is insulating for them,” she said.

Reif and Fredericks also point to what is known as the “acorn effect.” Milder weather and a surge in acorn production over recent years have fed an increase in small mammals such as mice, deer and squirrels, key hosts for ticks seeking food.

A strong “mast year” of acorns can result in more wildlife, leading to a proliferation of tick hosts and a greater possibility for disease transmission.

Ticks do not carry pathogens when they hatch but acquire them from infected host animals. More mice and squirrels therefore mean additional hosts and potential carriers of disease.

Although Lyme disease dominates public awareness, experts caution that ticks are spreading a growing list of pathogens. Besides Lyme, diseases such as ehrlichiosis, anaplasmosis, Rocky Mountain spotted fever, babesiosis, tularemia and tick paralysis have been observed in various regions.

According to Reif, Lyme, ehrlichiosis and anaplasmosis are most prevalent in dogs and their owners, with their spread forecast to expand in 2026. The Companion Animal Parasite Council, which monitors such diseases, projects these infections with an accuracy rate exceeding 94 percent.

Early signs of ehrlichiosis and anaplasmosis often resemble the flu, but if untreated can lead to serious complications including respiratory and organ failure, bleeding and neurological damage, according to the CDC.

Lyme disease can produce a wide range of symptoms from rash and fever to more severe effects like joint pain, facial paralysis and heart irregularities.

“We have the traditional hot spots where these tick‑borne diseases are most common,” said Reif. “And as years go on, these zones never really contract. They only continue to expand.”

Experts uniformly stress prevention as the most effective tool. Homeowners can reduce risk by landscaping to limit tick‑friendly environments, installing boundaries between lawns and wooded areas and keeping grass trimmed.

Pet owners are advised to discuss flea and tick prevention or vaccination options with their veterinarians, and to check animals regularly for parasites after outdoor activity.

The CDC recommends checking the body closely after spending time outside, paying special attention to warm, hidden places where ticks might attach. Proper clothing can also reduce exposure.