Of the five tick species encountered by humans, three — the American dog tick, the blacklegged tick and the lone star tick — are known to transmit diseases to humans, the public health department states. In Illinois, the most common diseases associated with tick bites are Lyme disease, Rocky Mountain spotted fever and ehrlichiosis.
Ticks – which are actually arachnids and not insects, as commonly thought – are divided into two categories, hard ticks and soft ticks. Hard ticks have a hard shield behind their mouth parts and are shaped like a flat seed when they are unfed, while soft ticks do not have a shield and more typically resemble a raisin in shape, the Department of Public Health reports.
The species most often "picked up" by humans are the hard ticks commonly found in Illinois. Soft ticks, on the other hand, feed on bats and birds and are not usually encountered by humans unless they are nesting or roosting in a building.
After ticks hatch, they must consume blood from humans and other animals for survival. Because they feed on different animals during different stages of their lives, they can pick up diseases and transfer them to their hosts.
Tick-borne diseases can range from mild to severe, and many of the illness have similar symptoms, including fever, chills, body aches and pains, and a rash, the CDC reports. Rashes can vary depending on the illness. For example, with Lyme disease, a target- or bullseye-shaped rash is often the hallmark and typically develops before other symptoms. The rash that accompanies Rocky Mountain spotted fever can vary greatly from person to person, but typically starts as small, pink-colored, non-itchy spots that later proceed to a reddish or purple-colored spotted rash.
The CDC advises anyone who experiences a tick bite and develops symptoms associated with tick-related illness within a few weeks of the bite to consult a health-care provider.
Protecting Yourself from Tick Bites