Many of us make a habit of ignoring warning signs even when we are aware of the risk.
We roll through stop signs, smirk at the numbers on the bathroom scale and shrug off reminders about filing income taxes.
Sure, it's in our best interests to pay attention, to be more careful -- but we often don't.
That's why last week's warnings about Lyme disease raise some disturbing red flags that should be taken seriously.
The Lake County Health Department said the 20 cases reported this year is a record. Suburban Cook County said it has seen 22 cases, up dramatically from the past two years.
But the disease might be even more prevalent, based on preliminary estimates from the Centers for Disease Control and Prevention in Atlanta. CDC officials said extensive studies and surveys show the number of Americans diagnosed with Lyme disease has been underreported by doctors. They put the number at around 300,000 -- 10 times greater than what is reported yearly.
What that means, experts say, is many people may have been bitten and infected by the deer tick that carries the disease but ignored symptoms and warning signs and didn't seek medical care.
That's risky because a tiny deer tick infected with the bacteria packs a wallop.
Lyme disease is characterized by -- here's one of those warning signs -- a bull's-eye rash or lesions around the bite site accompanied by flu-like symptoms, such as fever, fatigue, headaches and muscle or joint aches, generally seven days or more after the bite.
It can be treated with antibiotics. If untreated, some patients develop arthritis, including episodes of swelling and pain in large joints, abnormalities such as aseptic meningitis, facial palsy or encephalitis.
In rare cases, there is inflammation of tissues surrounding the heart or an enlarged heart.
"It is a serious illness," Leslie Piotrowski, a Lake County Health Department spokeswoman, told the Daily Herald's Mick Zawislak. "We really want people to be aware of ticks and avoid being bitten."
Experts say one reason the disease may be unreported is that some people may have the flu-like symptoms but not the rash. Thinking they caught a cold or the flu, they ride it out instead of talking to their medical professional.
Lake County health officials also stressed the deer tick is not some exotic bug. It can hitch a ride during your trip to a forest preserve or while you work in your yard.
None of this means you should avoid the great outdoors. But experts say -- here's another warning sign -- you can take precautions to stay healthy. They include keeping grass mowed around your home, applying insect repellent containing 30 percent or less of DEET to clothes or exposed skin and steering clear of high grasses and bushes.
Heed the warning signs about Lyme disease because it's just not worth the risk.