At the end of the summer in 2002, Mary de Lisser and her husband went on a camping trip near Courtenay, B.C. On their last day, she noticed a round mark on her calf. It kept getting bigger, and by the next afternoon it was the size of an orange and felt hot and tight. The Abbotsford resident went to see a doctor, who said it was a bug bite, possibly a spider bite, and told her not to worry about it. She took his advice, and the mark eventually faded. But her health drastically deteriorated over the ensuing months. It wasn't until the following June that another doctor told her she had Lyme disease as a result of being bitten by a tick.

"I was sick from head to toe," the 54-year-old says on the line from her home. "I had muscular and skeletal pain, neurological and cognitive effects, gastrointestinal problems. The pain was the worst, but the hallucinations were the scariest."

De Lisser began researching the disease on the Internet and saw a picture of a bull's-eye rash, which is a classic sign of a tick bite. "I thought, 'Holy mackerel, I had one of those on my leg.' I started reading about the symptoms and everything clicked."

Her new doctor prescribed antibiotics, which she took for 15 months. Although she's no longer taking medication, de Lisser says she can't work, limps, is fatigued, still experiences pain, and has ongoing cognitive difficulties.

"My story is the same as everyone else's," she adds. "Doctors had no idea what it was, other than it was systemic. They were considering multiple sclerosis.…Other people have been told they have ALS [amyotrophic lateral sclerosis], arthritis, or Crohn's."

Lyme disease in Canada is caused by a bacterium called Borrelia burgdorferi that's normally carried by mice, squirrels, birds, and other small animals, according to the Public Health Agency of Canada. It can be passed to humans when ticks feed on infected animals, become infected themselves, then bite people.

The health agency reports that two species of ticks are known to transmit the disease in this country: the western black-legged tick, which is established in parts of southern British Columbia; and the black-legged tick (also known as deer tick), which exists in parts of Ontario, Manitoba, and Nova Scotia. In B.C., tick populations are largest in the Lower Mainland, on Vancouver Island, and in the Fraser Valley.

"However, surveillance has shown that migratory birds can carry these ticks to other parts of Canada," states the PHAC Web site. "In addition, researchers believe the ticks may be establishing themselves in areas that are not identified yet. This means there is a risk that people in other regions of Canada may also be exposed to infected ticks."

According to the Westbank, B.C.–based Canadian Lyme Disease Foundation ( www.canlyme.com/ ), signs of the condition include initial flulike symptoms such as fever, headache, nausea, jaw pain, light sensitivity, red eyes, muscle aches, and stiffness in the neck. Those are followed by a vast range of other symptoms that sometimes fluctuate, including sore throat, blurry vision, plugged ears, diarrhea, chest pain, night sweats, confusion, dizziness, and slurred speech. The classic bull's-eye rash (erythema migrans) doesn't appear in everyone, so a lack of rash doesn't rule out the presence of disease. There might be more than one rash, and they can vary in size and appearance.

The foundation claims that people with the condition are frequently misdiagnosed with such illnesses as fibromyalgia, lupus, chronic-fatigue syndrome, irritable-bowel syndrome, depression, and Alzheimer's.

Lyme disease can be diagnosed through blood tests, but according to the U.S. Centers for Disease Control and Prevention, the tests may be falsely negative in the early stages of the illness. If untreated, Lyme disease can affect musculoskeletal, nervous, and cardiovascular systems and develop into a chronic condition that's hard to treat. The Public Health Agency of Canada states that Lyme disease can be treated effectively with antibiotics but that full recovery is more likely when treatment begins in the early stages of the disease. Fatalities from Lyme disease are rare, but during pregnancy it can cause serious health problems in the baby, including stillbirth.

In British Columbia, the B.C. Centre for Disease Control reports, there have been more than 60 confirmed cases of Lyme disease to date. De Lisser questions that figure, though, and says she believes the incidence is much higher. In the U.S. in 2005 alone, according to the CDC, there were 23,305 reported cases.

The BCCDC warns that anyone who's going to be spending time outdoors between May and November should take precautions to prevent tick bites. The tiny insects are usually found on the tips of grasses or shrubs and can be passed to people brushing past the vegetation.

The Public Health Agency of Canada recommends walking on cleared trails wherever possible instead of in tall grass or woods. Wear light-coloured clothes, tuck your top into your pants, and tuck your pants into your boots or socks. Use insect repellent containing DEET. When you're leaving a wooded or forested area, check your clothing, skin, and scalp for ticks. And check household pets that wander into tall grass and wooded areas for ticks as well.

If you find a tick embedded in the skin and want to remove it yourself, use tweezers to carefully grasp the insect and pull slowly upward, avoiding twisting or crushing it. Do not try to burn, smother, or douse the tick. Cleanse the bite area with soap and water, alcohol, or antiseptic. Save the tick in a secure container and send it to the BCCDC's vector-borne diseases laboratory for testing.