May 9, 2012, 10:11 a.m.
Meet the Ixodes Scapularis (otherwise known as the disease-carrying tick that could ruin your summer). Thanks to warmer temperatures, this ugly little bug has become a most unwelcome U.S. import, moving further north with each passing year, and flourishing in some of the most populated parts of Canada. (Complain about those bitterly cold Saskatchewan winters if you like, but prairie campers are less likely to be tweezing the hard-shelled bloodsuckers off their bodies.)
Know thine enemy: Black-legged ticks are arachnids (related to spiders and scorpions) with hard oval bodies in shades of brown, and short legs. Depending on their life cycle, they come as small as a poppy seed, though they can swell to twice their size the longer they feed on an animal – humans included.
Thank you, climate change: Ticks travelled up from the United States via deer and migratory birds, and the first populations began to grow along the border, from Nova Scotia to southern Manitoba. Warmer temperatures are the primary reason why the numbers have exploded, according to a recent Canadian study. In 2010, about 18 per cent of inhabited parts of eastern Canada had ticks – by 2020, that’s expected to rise to 80 per cent. (A West Coast version of the black-legged tick, Ixodes pacificus, which also carries Lyme disease, is making its own steady advance into British Columbia.) “If we have conditions in the future where temperatures are warmer than they are now, that’s going to speed the spread of ticks in new areas,” says Patrick Leighton, an assistant professor of Veterinary Medicine at the University of Montreal who co-authored a recent study tracking the tick invasion. “The public health issues raised with that will be confronting us more quickly.”
How they make us sick: Ticks transfer a bacteria called Borrelia burgdorferi, which causes Lyme disease. It’s been around for a while: This week, Italian doctors reported finding evidence of Lyme disease in a blood sample from a 5,000-year-old “iceman.” In the United States, 30,000 cases of the illness are reported annually, but in Canada, where doctors have been reporting incidences only since 2009, just 150 cases have been documented each year (of which half were contracted outside the country). But Nicholas Ogden, a research scientist and Lyme disease expert with the Public Health Agency of Canada, says that Canadian numbers are underestimated and expected to rise. The illness typically (though not always) begins with an bull’s-eye rash around the bite area, and flu-like symptoms. If it is not quickly treated with antibiotics, it may progress to joint pain, extreme fatigue, Bell’s Palsy, meningitis or heart palpitations.A tick has to be attached for about 24 hours to spread the bacteria. The risk of contracting Lyme disease is higher in the late spring and summer, when ticks “wake up” from their winter dormancy, and barbecues and nature walks make us more likely to encounter them.What to do if you get bitten: Don’t yank a tick off, like a mosquito. The public-health agency recommends using tweezers to gently pull the tick away at the closest part of the skin. If it’s possible the tick has been attached for more than 24 hours, and especially if you are in an area with a reported incidence of Lyme, contact your doctor. Federal health guidelines say that Lyme disease can be diagnosed clinically (without a lab test), and conclusively if the rash appears (so take a picture), and then treated promptly with antibiotics. However, symptoms may not develop immediately.
The controversy: The sooner you get treated, the better the outcome, but since the disease is still making inroads into Canada, not all doctors are familiar with it. The general symptoms of Lyme disease fit many other illness, so patients without evidence of a bite or who only start feeling sick weeks later, are often misdiagnosed. The testing for Lyme disease, like many illnesses, isn’t perfect – false positives and negatives are common, and there is an ongoing debate about the quality of testing that has led some Canadians to pay for further lab work in the United States (or even seeking treatment there). A small portion of patients experience debilitating symptoms long after their initial antibiotic treatment. While some physicians, who believe that leftover but well-hidden bacteria may be causing the illness to flare again, advocate prescribing long-term antibiotics, this treatment is challenged in the mainstream medical community. “All the science has not been done, that’s the problem,” says Pat Smith, the president of the U.S. Lyme Disease Association, which this week launched a billboard in Time Square to raise awareness and research dollars: “All over the world … Throughout the body. Chronic Lyme Disease – Are you next?”
Tick Check - a game the whole family can play: Prevention is the best defence. That means, for example, cutting long grass around walking trails in wooded areas (many parks now post warning signs for hikers), keep your lawn short, and checking your pets for ticks they might bring into the house. If you walk in tick-infested areas, cover as much skin as possible and avoid wearing sandals. Regularly check every member of your family for the tiny bugs, especially under clothes, and hard to see places such as behind the knees. (Usually, you can feel them by rubbing your hands along your skin.) But don’t panic: With proper prevention “we are not entirely helpless in the face of this emerging risk,” says Dr. Ogden, pointing out that, “Staying home to watch the tely and eat chips is not a healthy option compared to pursuing activity in the great outdoors.”