McHenry County Department of Health - Environmental Health
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Frequently Asked Questions on Ticks and Tick-borne Disease

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Q: What is Lyme Disease?
A: Lyme Disease is the most common tick-borne infection in North America and is transmitted through the bite of an infected tick.

Q: If I am bitten by a tick, does that mean that I will develop a tick-borne illness?
A: No, not all ticks carry disease. It is impossible to tell by sight which ticks are infected, so it is important to avoid tick bites whenever possible.

Q: Do all ticks transmit Lyme Disease?
No. Not all ticks carry the bacterium and a tick bite does not always result in the development of Lyme Disease.

Q: Which tick-borne disease is most common in Illinois?
A: Lyme Disease is the most common tick-borne disease in Illinois. Keep in mind that the bite of a deer tick can occur while traveling to Wisconsin, Minnesota and other surrounding states.

Q: Which tick transmits Lyme Disease?
A: In Illinois, the tick which transmits Lyme Disease is the Black-legged or Deer Tick.
Q: How common is the Black-legged or Deer tick in Illinois?
The deer tick is well established in some areas in Illinois, especially along the forested river corridors. That is not to say that you will not encounter ticks anywhere in the State.

Q: How do ticks acquire Lyme Disease?
Deer ticks acquire the bacterium that causes Lyme Disease by feeding on small mammals infected with the bacteria. The Deer Tick has a two year life cycle, and can acquire the disease at any feeding during that two year cycle.

Q: What are the symptoms of Lyme Disease?
Symptoms vary greatly from person to person. A ring-like or bulls eye rash occurs in about 70 - 80% of the cases. This rash is often accompanied by fatigue, chills, fever, headache, swollen lymph nodes and joint and muscle pain.

Q: When should I seek medical attention?
If you experience a rash or any unexplained illness accompanied by fever and have had possible tick exposure, consult with your physician. Explain that you may have been bitten by a tick.

Q: Can Lyme Disease be treated?
Yes. The usual course of treatment for Lyme Disease is antibiotics. The type and use varies depending on the patient’s symptoms and whether he/she was treated early in the infection.

Q: What is the prognosis of Lyme Disease?
Patients treated with antibiotics in the early stages of the infection usually recover rapidly and completely. Most patients, who are treated in the later stages of the disease, respond well to antibiotics. Varying degrees of permanent damage to joints or the nervous system can develop in patients with late Lyme Disease. Lyme Disease is rarely life threatening.

Q: How can I avoid getting bit by a tick?
The best way to avoid tick bites is to avoid tick infested areas. If you are in wooded areas with tall grass and weeds, follow these precautions:

  • Wear light colored clothing, so you can spot a tick on your clothing.
  • Wear long sleeved shirts and long pants. Tuck pant cuffs into socks.
  • Apply insect repellent containing DEET (up to 30%) to clothing and sparingly to skin. Always wash hands after using any insect repellent and follow label directions.
  • Walk in the center of trails so weeds do not brush up against you.
  • Check yourself and your children every two to three hours for ticks. 

Q: How long does it take for a tick to transmit Lyme Disease?
In general, a tick needs to be attached for 36 hours before they can transmit the Lyme disease bacterium.

Q: Can I only get Lyme Disease if I have been in the woods or tall grassy areas?
NO. Ticks can also be carried by animals into lawns and gardens and into houses by pets.

Q: Which diseases can be transmitted by the bite of an infected tick?
The most common diseases transmitted by ticks are Rocky Mountain Spotted Fever, Ehrlichiosis, Lyme Disease and Tularemia.

Q: What is Rocky Spotted Fever?
Rocky Mountain Spotted Fever is an infectious disease transmitted to humans by the bite of an infected tick. Symptoms of Rocky Mountain Spotted Fever are a sudden onset of a fever (which can last for two to three weeks), severe headache, fatigue, deep muscle pain, chills and rash. The rash typically begins on the legs or arms.

Q: In Illinois, which tick carries the disease for Rocky Mountain Spotted Fever?
The most common carrier is the American Dog Tick. The adult tick is dark brown or black, with white markings behind the head. The Lone Star Tick has been known on occasion to carry the disease.

Q: What is Ehrlichiosis?
Ehrlichiosis is a disease of humans and animals caused by bacteria that are transmitted through a bite of an infected tick. The Lone Star Tick, the American Dog Tick and the Deer Tick have been associated with this disease.

Q: What are the symptoms of Ehrlichiosis?
Symptoms vary, but the most common include fever, headache and muscle aches. A person may experience loss a appetite, nausea and vomiting, occasionally accompanied by a rash.

Q: What is Tularemia?
Tularemia is a bacterial disease associated with animals and humans. Not known to spread from person to person, people may become infected with Tularemia through: 

  • Bite of an infected tick, deerfly or other insect
  • Handling infected bodies of dead animals
  • Eating or drinking contaminated food or water
  • Breathing in the bacteria

Q: What are the symptoms of Tularemia?
The symptoms from Tularemia may include, fever, chills, muscle pain and lack of energy. Antibiotics are used to treat Tularemia.

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