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Health officials report that warmer temperatures and increased outdoor activities are contributing to the rise in hospital visits for tick-borne diseases. 

The Minnesota Department of Health has observed an increase in emergency department visits related to tick bites over the past few months. This rise is consistent with the annual increase in tick-borne diseases. The number of visits appears to surpass the typical baseline seen during the colder months.

Dr. Diana Zychowski, an infectious diseases physician-scientist at Hennepin Healthcare, noted a trend in the number of reported cases based on years of surveillance data. She said that many of her friends and family are returning from their camping trips covered in multiple tick bites, a troubling phenomenon they have never encountered before this year.

This increase in tick-related bites suggests a possible shift in their behavior or habitat, raising concerns about public health during the outdoor season.

Not all ticks in Minnesota spread diseases

There are over 900 species of ticks worldwide, and Minnesota is home to about a dozen circulating tick species, but not all of these ticks spread diseases.

The most frequently encountered ticks in the state are the American dog tick, also known as the wood tick, and the blacklegged tick, referred to as the deer tick. While reports of the Lone Star tick exist in Minnesota, this species is rarely found in the state. Still, it can transmit diseases such as 

, which can be fatal for pets and life-threatening for humans if left untreated.

Ticks can carry various pathogens that lead to different diseases, according to Zychowski. While wood ticks bite people in Minnesota, they seldom transmit diseases. The most prevalent tick-borne infection in the state is Lyme disease, a bacterial illness primarily transmitted to humans through the bite of an infected deer tick. Zychowski said this pattern is consistent with what is observed nationwide, as an estimated 

 are diagnosed and treated for the bacterial infection each year.

Other types of infections commonly seen in Minnesota, aside from Lyme disease, include those that affect red blood cells, potentially leading to anemia or severe illness, according to Zychowski.

Though present in Minnesota, pathogens such as the 

 are found to a lesser degree. Zychowski also said there is a new tick-borne disease, known as Alpha-Gal syndrome, which is a tick-induced allergy that predisposes individuals to hypersensitivity reactions to eating red meat.

What ticks eat may determine what kind of disease-producing bacteria they carry

Benjamin Clarke, a professor of biomedical sciences at the University of Minnesota Duluth’s Medical School, studies ticks and the pathology of Lyme disease. “Somehow, I became an outdoor arthropod investigator,” he said.

Clarke wants to find out where ticks that carry Lyme disease are common and where they are less prevalent. He's studying the microbiome of ticks to understand why some have more Lyme bacteria than others.

A tick's diet may influence what kind of bacteria it carries, including the one responsible for Lyme disease. Clarke's team is exploring that relationship.

The main host for these bacteria is the white-footed deer mouse. Clarke said ticks feed on the mouse, pick up the bacteria, and can spread the disease when they bite humans or other animals.

“This bacterium has been in this area for a long time,” Clarke said. “On an evolutionary level, the mouse probably evolved and appeared about 40,000 years ago, during the Ice Age, and the tick itself adapted to it. Climate change and the way we alter the environment make it a bit more hospitable habitat for deer mice, and more deer mice means more Borrelia and more ticks.”

 has prompted blacklegged ticks to move north and reclaim territory they once inhabited. Clarke explained that warmer winters and extended temperatures in spring and fall enable ticks to survive in areas that were previously inhospitable environments, expanding the ranges of animals, like migratory birds and deer, that transport ticks.

Most ticks live in wooded and brushy areas and serve as prey for white-footed mice and other mammals. The highest risk of tick exposure occurs along trails and at the edges of woods.

Clarke likens ticks to tiny snare traps that position themselves on leaves, grass blades, or low-hanging branches. “They hang their arms out, kind of like they're grasping,” he said. “The term for that is called questing.” 

As people pass by, ticks detect motion, vibrations, and carbon dioxide from exhaled breath, allowing them to latch onto a passing person for a blood meal. “A deer tick is probably about the size of a small seed,” Clarke said. “You really have to actively look for them.”

If a tick latches onto your skin or clothing, the Minnesota Department of Health advises remaining calm. Health officials recommend removing the tick as soon as possible to reduce the risk of transmitting tick-borne diseases by using a pair of tweezers to grasp the tick as close to the skin as possible and pull steadily and slowly.

Clarke’s lab is keen to evaluate ticks for Lyme disease. He encourages people to send him their ticks. “Put the tick into a little baggie with a little bit of hand sanitizer,” Clarke said. “Mail it to me at the University of Minnesota Duluth Medical School."

To prevent tick bites, health officials recommend using repellents like DEET, showering after outdoor activities, and placing clothes in a hot dryer for 10 minutes after coming indoors.

Elizabeth Schiffman, supervisor of the Minnesota Department of Health’s Vectorborne Diseases Unit, emphasized the importance of enjoying the beautiful spring and summer weather while also taking precautions.

“If people are out at this time of year, it’s a good idea to be aware that the ticks are out as well, so this is the key time of year to implement prevention measures,” Schiffman said. “I often say that if it’s a time of year where you are thinking about sunscreen for outdoor activities, you should probably also be thinking about insect repellent.”

Schiffman added that if a person finds a tick on themselves, it's essential to monitor for symptoms such as fever, aches, flu-like symptoms, or rashes in the following weeks.

“A tick bite alone is typically not cause for concern, but it is important to keep an eye out for symptoms just in case,” Schiffman said.

Recent data assessing the effectiveness of a Lyme disease vaccine developed by 

 show promising results, indicating that the vaccine could reduce the risk of a person developing Lyme disease by more than 70 percent. The companies are now working towards regulatory approval for the vaccine.

While a vaccine may be available in the future, there are tests and treatments for many tick-borne infections, although not all have effective treatments, according to Zychowski from Hennepin Healthcare. She emphasized the importance of consulting a healthcare provider if there is a concern about tick exposure.

“If someone has a tick bite with an attached tick, and that tick is identified as a blacklegged tick, that person qualifies for doxycycline post-exposure prophylaxis within 72 hours,” she said. “Getting to a healthcare provider as soon as symptoms develop could lead to treatment for early-stage disease and help prevent the onset of Lyme disease.”

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Erica Zurek

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Health experts emphasize early detection and prevention as tick activity increases statewide.

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