The small, blacklegged ticks that cause Lyme disease are popping up in new regions across the country, prompting the Public Health Agency of Canada to develop new maps to educate the public about the spreading risk.
The tick population in Canada used to be confined to one region of Ontario, on the Long Point peninsula in Lake Erie.
But in the past 10 years, the bugs have spread across the country, carried by the birds on which they feed, and Public Health says doctors should no longer rule out infection because of geographic location.
"What we've seen is definitely an expansion," said Robbin Lindsay, a research scientist with the agency.
"Tick populations are expanding into new areas and in different provinces where we haven't seen them before."
The agency has now confirmed populations in B.C.'s Lower Mainland, on Vancouver Island, in the southeastern corner of Manitoba, along the shores of Lake Erie and Lake Ontario and within Nova Scotia, where the critters appear to be moving inland from the coast.
"We're investigating a third location in Nova Scotia this month," he said. "There's a good chance there'll be a new dot on the map."
There have also been human cases of Lyme disease corresponding with the spread of the bugs across the country, and Dr. Lindsay expects the numbers to grow as the ticks establish new habitats.
Lyme disease can have devastating effects for those it infects. It can often be hard to diagnose, which can result in months of suffering and confusion.
The organism responsible for the disease moves through a person's tissue, eventually embedding itself in the central nervous system, heart, brain, liver, spleen and joints, causing everything from mild pain and dizziness to paralysis.
For many, the first sign is a circular rash that appears from three days to a month after a tick bite.
This can be followed by fatigue, chills, fever, headache, muscle and joint pain, and swollen lymph nodes.
Although the disease is easily treated with antibiotics, if it goes undiagnosed it can progress to migraines, skin rashes, stiff joints, an abnormal heartbeat and extreme fatigue, and can potentially result in chronic arthritis and neurological symptoms, including paralysis.
The official number of reported cases of Lyme disease in Canada remains relatively low, with approximately 300 cases since 2004, according to Health Canada.
But a growing number of Canadians are sending blood tests south of the border for diagnosis. In the United States there are more than 20,000 cases each year, and some believe the disparity in diagnoses may be because many Canadian physicians still believe ticks are not endemic in Canada.
"The doctors will just say there are no ticks around here, even if the patient has just been bitten by one," said Jim Wilson, president of the Canadian Lyme Disease Foundation, whose own diagnosis took years. "They're sending people away who are clearly suffering."
In the past, some physicians have ruled out a Lyme disease diagnosis if their patient lived in an area not known to be home to ticks. But Dr. Lindsay said geographic location can no longer be tied to Lyme disease risk.
"They should not rule out Lyme disease because they're 10 or 20 or 100 or even 500 kilometres from an established population," he said. "It's possible that a person could be bitten by an infected tick far from an endemic area."
Lyme disease is often mistaken for everything from arthritis and fibromyalgia to chronic fatigue syndrome, multiple sclerosis, Lou Gehrig's disease, Parkinson's, Alzheimer's and bipolar disorder.
An effective way to avoid infection is to check for ticks and remove them as quickly as possible with tweezers. Grab the tick as close to the skin as possible and pull it straight out without twisting or crushing it.
Public Health is in the process of developing a risk map to show the new tick populations, and is trying to predict their spread by studying patterns of bird migration and the impact of climate change.
Dr. Lindsay believes the map will be ready later this year and says the agency is also informing doctors of the new reality of Lyme disease through peer-reviewed journals and other publications read within the medical community.
"It really is an evolving situation," he said. "Where the boundaries of that population end are often difficult to define. The risk is never zero."