Tick Bites Causing Increased Emergency Room Visits: See Where CA Stands

CALIFORNIA — Emergency rooms across the country are seeing a spike in visits for treatment of tick bites and tick-borne illnesses, especially in the Northeast and Midwest, according to new data from the U.S. Centers for Disease Control and Prevention.

In California and other western states, the figures aren't as high, but are still worth watching, according to health officials.

Nationally, from Jan. 1 to July 6 of this year, 447 ER visits per 100,000 visits were for tick bites, according to the CDC’s tick bite data tracker. That compares to 509 per 100,000 ER visits for the entire year of 2024.

According to the data, 116 visits per 100,000 ER visits in June alone this year were for tick bites. U.S. emergency rooms haven’t seen this level of tick-related visits during June since 2019. The highest rates of ER visits are among young children under 10 and older adults over 70, the CDC said.

In the Northeast, there have been 127 tick-related ER visits per 100,000 visits from Jan. 1 to July 14. In the Midwest, it was 85 per 100,000 ER visits reported for the same period, according to the CDC.

In the West, just 16 tick-related ER visits per 100,000 ER visits were reported for the same January through July period. However, for the entire year of 2024, the number was 11 visits per 100,000, according to the CDC data.

California's 2025 numbers could increase dramatically. The summer months traditionally see the lowest risk of exposure to infected Western blacklegged (Ixodes pacificus) ticks in California, according to the state's Department of Public Health.

In California, the Western blacklegged is the tick family's biggest disease spreader, primarily responsible for Lyme Disease in humans.

Come Halloween time, adult Western blacklegged ticks become very active in California, and this continues through early spring, according to the CDPH.

During the spring season, nymph Western blacklegged ticks arrive.

"Nymphs are most active in spring and early summer. These tiny ticks pose a greater risk of transmitting disease than adult ticks," the CDPH reports.

But the dog days of summer are not a good time to let your guard down against ticks, even though they are less prevalent in California during this period.

"The risk of tick bites is lower during the summer months, but ticks are active all year round in California," according to the CDPH.

Why Are Tick Bite Cases Surging In Parts Of The Country?

Tick populations have reached a record high in several states this year due to a combination of factors, including climate change, Dr. Dennis Bente, a professor of microbiology and immunology at the University of Texas Medical Branch, told CBS News. That has extended the tick season, he said.

"While tick bites are more common in the summer [in parts of the country] because of increased outdoor activity, evidence shows that people must stay vigilant year-round now that ticks are also active in the winter because of warming driven by climate change," Bente said.

Tick-Borne Illnesses Have Similar Symptoms

Many of the diseases that ticks spread through their bites have similar symptoms, including fever and chills, headaches, fatigue, and muscle aches. Patients with two of the most serious diseases, Lyme disease and Rocky Mountain spotted fever, also develop distinctive rashes.

According to the CDPH, tick-borne diseases in California also include:

• Anaplasmosis
• Babesiosis
• Tick-Borne Relapsing Fever
• Tick Paralysis
• Tularemia

U.S. health officials are also increasingly concerned about the spread of the aggressive lone star tick, which is linked to a mysterious meat allergy and whose larvae travel in what are colloquially called “tick bombs.”

The tick is identifiable by the white starlike splotch on the backs of adult females, and the larvae hunt in packs — hence, the tick bomb moniker. The tick is widely distributed in the eastern, southeastern, and south-central United States.

Scientists are unsure why some people bitten by the lone star tick develop a potentially life-threatening allergy to the red meat protein alpha-gal and others don’t, or if the allergies were triggered by something other than the tick bite. AGS, as the allergy is known, can be difficult to diagnose. Unlike other allergies, the symptoms may not appear for several hours after eating red meat. Some people develop an allergy to other products from mammals, including dairy products, and some may develop an allergy to certain medications. There is no known cure or treatment.

What You Should Do

If a tick bites you, the CDC recommends promptly removing it with fine-tipped tweezers, cleaning the bite area, and monitoring for symptoms like fever, rash, or flu-like symptoms for 30 days. If symptoms develop, see a doctor.

The best thing to do is to protect yourself against tick bites. Ticks live in grassy, bushy or wooded areas. Spending time outside, such as walking your dog, camping, gardening, or hunting, can bring you into close contact with ticks. Many people contract ticks in their own yard or neighborhood, according to the CDC.

The CDC recommends treating clothing and gear with products containing 0.5% permethrin before venturing into outdoor areas. Environmental Protection Agency-registered insect repellents are also a good idea. The EPA offers a search tool to help you find the product that best suits your needs.

For more information about ticks and tick bites in California, visit the CDPH's tick portal.