McHenry County Department of Health - Environmental Health
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Ticks and Lyme Disease

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Ticks and Tick-borne Disease

Deer TickMore than 15 species of ticks are found in Illinois, but the three most prominent are the Black-legged Tick, or Deer Tick, the American Dog Tick, or Wood Tick, and the Lone Star Tick.  In general these ticks are most active from March through November. 

Ticks are not insects; they belong to the arachnid family (i.e. scorpions, spiders, mites). Ticks do not jump or fly, instead they climb or drop.  They wait in tall grass or weeds for a suitable host to pass by.  When brushed by a moving animal or person, they let go of the plant and climb onto the host.

Ticks are very skilled disease carriers because they attach firmly, feed very slowly and often go unnoticed.  Their sensory organs can track small amounts of gases, such as carbon dioxide left by warm blooded animals and man.  It is impossible to tell by sight which ticks are infected with disease, so it is important to avoid tick bites when in areas where ticks may be present.

The risk of tick exposure is greatest in wooded areas, but ticks can also be carried by animals into houses by pets.

For tick identification and testing services, click here.


Common Ticks of Illinois Lyme Disease
Tick Life Cycle Protecting Yourself from Ticks
Tick Removal  FAQs
Educational Materials Tick Identification and Testing Services



Deer Tick-Thumb
Relative Size of a Deer Tick

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