A report from the U.S. Centers for Disease Control and Prevention (CDC) says illnesses from mosquito, tick and flea bites have tripled since 2004. Tick-borne diseases are the biggest threat, accounting for more than 60% of cases. In the Midwest, milder winters may be somewhat to blame for the abundance of ticks because climate change can have a major impact on arthropods and the animals they feed on. 

The change of even one degree can affect the survival rate of the insects and their population size, according to infectious disease specialists with the Froedtert & the Medical College of Wisconsin health network. The warmer the climate, the more of this we can expect and the more important prevention efforts become. 

The distribution of ticks in Wisconsin and throughout the United States changes over time due to many things, including climate change, as well as the fact that ticks can act as “hitchhikers,” attaching themselves to migratory birds or other animals and people, helping them quickly populate new areas.

What Is Lyme Disease?

Lyme disease is a bacterial infection caused by Borrelia burgdorferi and possibly Borrelia mayonii, a newly discovered bacteria similar to Borrelia burgdorferi. Humans come into contact with the bacteria through a tick bite.

Lyme disease is the most common tick-borne disease in the United States with about 476,000 cases diagnosed and treated, while only 35,000 cases are reported to the Nationally Notifiable Diseases Surveillance System

“When an infected tick bites the skin, bacteria are inoculated where the tick is feeding,” said Jenifer Coburn, PhD, a professor at the Medical College of Wisconsin who studies Lyme disease-causing bacteria. “It takes at least 24 hours for Lyme disease bacteria to be transmitted because the bacteria need to change their own gene expression to infect an animal. There are other pathogens that can be transmitted in a matter of hours. In general, the longer a tick is attached, the higher the risk of infection.”

Do All Ticks Transmit Lyme Disease?

In Wisconsin, there are at least 16 species of tick, but not all of them transmit disease to humans. Only one type of tick, Ixodes scapularis (commonly known as the black-legged tick or deer tick), carries and transmits Lyme disease. Contrary to what the tick’s name might imply, deer do not transmit Lyme disease bacteria to ticks. Deer are simply a common food source for the ticks. Also, not all of the Ixodes scapularis ticks are capable of transmitting Lyme disease. Only those that carry the bacteria can transmit it.
“Ticks become vectors for Lyme disease when they are larvae or nymphs, in their early stages of life,” Dr. Coburn said. “By feeding on small animals such as mice, chipmunks, squirrels or certain birds that are infected, the juvenile ticks will ingest the bacteria and can transmit them to their next food source.”

Other Tick-Borne Diseases on the Rise

There are five different types of infections that can be transmitted by the bite of the Ixodes scapularis tick  – Powassan virus, anaplasmosis, ehrlichiosis, babesiosis and Lyme disease.  While Lyme disease is the most prevalent, these other diseases are catching up.

Lyme Disease Symptoms

Early symptoms of Lyme disease can appear anywhere between three and 30 days after a tick bite, and they can often mimic symptoms of other diseases. It is important to talk to your health care provider about your symptoms and if you think you may have had a tick bite. 

A classic early sign that an individual has been infected with Lyme disease is erythema migrans, a rash that begins at the site of the tick bite and gradually increases in size.

 “A common first sign of a Lyme infection is a red, spreading patch on the skin that can sometimes be shaped like a bull’s-eye,” Dr. Coburn said. “It won’t be painful or itchy; it will simply look like a red spot that is at least two and a half inches in diameter and expands day to day.”

Erythema migrans is a rash development that gradually increases in size in a bulls-eye shape.

Early Signs and Symptoms 

  • Rash development -- erythema migrans
  • Flu-like symptoms that may include fever and chills
  • Enlarged or swollen lymph nodes
  • Muscle and joint aches
  • Fatigue

Later Signs and Symptoms in Untreated Individuals

  • Severe headaches
  • Facial palsy (drooping on one or both sides of the face)
  • Increased muscle and joint pain
  • Memory loss
  • Numbness or tingling due to nerve problems
  • Irregular heartbeat, known as Lyme carditis

Laboratory Tests for Diagnosing Lyme Disease 

Diagnosis relies on clinical observations and laboratory tests for the presence of antibodies against the B. burgdorferi bacteria. Since it can take several weeks for antibodies to develop against the bacteria, lab tests help confirm the diagnosis. If Lyme disease goes undetected and untreated, the disease will continue to progress and symptoms may appear months after the tick bite. Some patients who have untreated Lyme disease are hospitalized because the bacteria can affect the brain, the nervous system and the heart. 

The CDC recommends a two-step laboratory blood sample test to accurately diagnose Lyme disease. New tests are also being developed as alternatives to the two-step process but still require review and clearance from the Food and Drug Administration.

It is not always necessary to obtain a blood test to confirm early Lyme disease since the necessary protein antibodies in the blood that make a test positive may take many days to form. Thus, it is common to have a negative blood test early in infection.  If a patient is at risk and might have an infection early, it is usually better to treat for Lyme disease rather than rely on a blood test.  Blood tests are more helpful for late disease that may have gone untreated early in the infection course.

Lyme Disease Treatment

Treatment as soon as symptoms appear is important to prevent complications from the disease. In most early-stage cases, Lyme disease can be treated with oral antibiotics for a period of two to three weeks, and the patient can make a full recovery. With time, it becomes increasingly difficult to fight Lyme disease, though it is still treatable. In more advanced cases, hospitalization and intravenous antibiotics may be necessary.

For a small percentage of people, symptoms such as muscle aches, arthritis and fatigue can last for more than six months, even after treatment. This is commonly known as chronic Lyme diease.The cause of these symptoms is not known, and there is no laboratory proof that bacteria are still present. In these cases, studies funded by the National Institutes of Health have shown that extended antibiotic therapy is not helpful.

In 2020, the Infectious Diseases Society of America published a detailed updated set of free guidelines for the diagnosis, treatment and prevention of Lyme disease. These guidelines provide a wealth of data from clinical and laboratory research that was used to develop these recommendations.

Lyme Disease Protection

Taking steps to protect yourself and your family from ticks is the best way to ensure you stay healthy. While peak tick season is when ticks are most active particularly from May to September, the risk still exists from October to April, especially when temperatures are warmer.

Ticks should be removed as soon as possible per the CDC’s recommendations, with tweezers and by pulling upward with steady pressure. Tick removal tools (a plastic or metal v-shaped notch) and kits are widely available online and in some health care locations.  

It is strongly recommended to conduct a thorough tick check and examine clothing, hair and skin after spending time in grassy or forested areas. A close examination is important, as juvenile ticks can be the size of a poppy seed or smaller. Infectious disease specialists recommend people inspect their skin and scalp, and if a tick is detected, it should be extracted appropriately, photographed and saved in a bottle because it could provide helpful information.

“Putting the tick(s) in a sealable plastic bag in the freezer is another easy way to preserve them,” Dr. Coburn said. “When checking for ticks, be extremely careful, and look for a tiny, shiny freckle.”

Ixodes scapularis — commonly known as the deer tick or black-legged tick — transmits Lyme disease.

There are online resources that can help identify the most common ticks. If you discover that the tick you pulled off is not a black-legged tick, you do not have to worry about Lyme disease. Keeping the tick in a plastic bag can help you identify it by comparing it to photos online. For example, the very common dog ticks and wood ticks look quite different.

If you or someone you know thinks they have experienced a tick bite, they should consult with their primary care provider as soon as possible. 

Ways to Prevent a Tick Bite

  • Use insect repellent containing at least 20% diethyltoluamide (commonly known as DEET). Lemon eucalyptus oil is also an effective option to repel ticks. Consult EPA.gov to read more about which repellent is best for you
  • Use permethrin (an anti-parasitic product) to treat clothes, shoes, camping or hunting gear. Do not apply permethrin on skin.
  • Wear clothing that you can tuck into pants and socks to prevent ticks from getting on the skin. Light-colored clothing also helps you spot ticks easily.
  • Stay in the center of hiking trails and avoid areas with high grass and brush.
  • After being outside, do a full-body check, including in and around hair and clothes.
  • Check pets and any outdoor gear, as they can carry ticks into the house that can attach to a person. 
  • Shower as soon as possible after time outdoors.

Learn more about our infectious disease services and treatment.

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on June 12, 2019 - 5:08 pm

I don't see that any of the Infectious Disease specialists at Froedtert list "Tick Borne Diseases" as their specialty even tho it is listed on their Infectious Disease Clinic page. You would think in a state known for it's tic population/Lyme Disease, ect. there would be specialists in Milwaukee and SE WI to help those of us who suffer greatly with Lyme Disease.

on June 17, 2019 - 1:04 pm

Hello Shawn – Several of our Infectious Disease providers treat patients with lyme disease. If you would like more information or to schedule an appointment, please call 414-777-7700. Thanks.