After gardening in her Lake Villa, Ill., front yard last month, Lori Brunk noticed a tiny spot not much bigger than a sesame seed on her left foot. It was a tick burrowing into her skin.
She removed the eight-legged critter but soon developed a fever, joint pain and a rash around the bite. Her doctor put her on antibiotics for Lyme disease, and she said she's now feeling better.
"Unfortunately, it kind of puts a stop on your life and any plans you had," said Brunk, who said she contracted the disease once before and it caused constant pain and memory loss. "This little bug can change your life for a long time."
Lyme disease - known by its bull's-eye-shaped rash and flu-like symptoms - usually can be treated successfully with antibiotics, medical experts say. But without proper medical attention, the disease can cause lasting severe problems like arthritis, numbness and even paralysis.
And reported cases might only amount to a small fraction of actual infection, experts say. This week, the U.S. Centers for Disease Control and Prevention reported that, while about 30,000 cases of Lyme disease are reported annually, the actual number could be 10 times higher. Some patients don't seek treatment, the CDC said, some doctors don't report cases, and some cases are misdiagnosed.
In the decades since the malady was identified near Lyme, Conn., in 1975, the footprint of the disease has expanded from heavily wooded rural areas in the Northeast and Upper Midwest to some suburban Chicago backyards.
In each of the last two years, Illinois saw record-setting spikes in the number of reported Lyme disease cases, topping 200 new diagnoses last year alone. So far this year, reported cases are coming in under those record years, but certain areas - including Lake County, where 20 cases have been confirmed - have already topped 2012's highs.
Early on, infected black-legged ticks were not found in Illinois, and people who came down with the disease here were believed to have contracted it elsewhere.
But over the past 20 years or so, studies show, ticks that carry the disease have become increasingly common in Illinois. In Lake County, the first black-legged tick that carried the bacteria was found in 2006. Now, 40 percent of ticks tested there carry the pathogen, according to the county health department.
The bacteria can be carried by deer, birds and small mammals like mice and chipmunks down the Des Plaines River corridor from Wisconsin, said Mark Pfister, director of population health services for Lake County, Ill.
A couple of times while out in tick habitats, he said, he has found himself covered with hundreds of the bugs, so many he used duct tape to get them off without getting a bite.
"We don't want to scare people from going out, but just be aware, whether it's mosquitoes or ticks, take proper precautions," Pfister said.
Those precautions include wearing long pants, long sleeves and hats when going into wooded areas or tall grass, using insect repellent, and checking for ticks and taking a shower within two hours of being outside.
Homeowners can protect their yards by putting a 3-foot-wide buffer of gravel or wood chips where lawns abut wooded areas and brush.
On the medical front, researchers reportedly are trying to come up with a vaccine against the disease. One formulation would alert people by making them itch as soon as a deer tick bites, while another would kill the bacteria, but neither is publicly available yet.
Despite the research and educational steps taken by public health agencies, Lyme disease activists say much more needs to be done.
Some patients claim they have a chronic form of the disease that often goes undetected, misdiagnosed and untreated, and can cause a host of crippling symptoms.
"It's a huge problem," Kimberly Heeres-Frank, founder of the Lyme Support Network, which meets monthly in Ingleside, Ill. "It's a very debilitating disease."
The CDC says some cases go undiagnosed or misdiagnosed as arthritis or multiple sclerosis, and some people do not respond to the typical treatment, which involves several weeks of antibiotics. Not all cases show the classic target-shaped rash, the antibodies don't show up in tests for several weeks after infection, and some symptoms may not appear until months or years after a tick bite.
In addition to more frequent diagnoses, some local practitioners are running into more hard-to-treat cases.
In Crystal Lake, Ill., Dr. Benjamin Nager, a neurologist with Centegra Physician Care, said he has seen more local cases in the past five to 10 years, some with severe symptoms. Patients come in with headaches, numbness or weakness. One patient was deaf in one ear, and others have Bell's palsy, a paralysis of the face.
Most recent cases have responded well to antibiotics, he said, but those who've had multiple symptoms for months or years are much more difficult to treat.
Patients are often amazed, Nager said, that such serious problems could come from a bug bite. "It catches people by surprise. Many times they don't even know they've been bitten."
Explore further: Large-scale study of preventive antibiotic usage against Lyme disease