Tuesday, December 4, 2007

The Effects of Climate Change on Lyme Disease

Currently, Lyme disease is not a nationally reportable disease in Canada; however, this may soon change. The increased effects of global warming are creating an environment favorable to disease bearing ticks, even in typically cooler countries such as Canada. Lyme disease is typically transmitted by ticks carrying the infectious spiral bacteria. These ticks are highly sensitive to temperature change and are unable to survive in cold environments. For this reason, cases of lyme disease are usually reported in southern Manitoba, Ontario and BC where temperatures are milder.
Unfortunately, with global warming comes increased humidity and shorter winters, leading to a more hospitable climate for ticks and their hosts. Short winters mean a longer season for tick activity, allowing them to infect an increased number of hosts. Recent studies have shown that globally, tick activity is not only prolonged but is shifting further north geographically. Incidences of lyme disease have been reported in mountainous regions of Europe as well as Canada.
Within Canada, rates of lyme disease are expected to increase at quite a shocking rate. By the 2020s, the northern range limit of the disease is expected to shift a minimum of 200 kms. The range is only likely to increase exponentially from there. Currently, the Public Health Agency of Canada is researching just how dramatically global warming will affect disease rates in the country. It appears; however, that the spread of lyme disease is inevitable on a global scale.