Scientists long expected climate change to harm human health. But one of the clearest signs of health risks in a warming world has emerged in one of the world’s most advanced economies, as Canada belatedly struggles to cope with Lyme disease's migration in North America.
Canada should have seen this coming. In the United States, reported cases of Lyme disease have increased from fewer than 10,000 reported cases in 1991 to more than 27,000 cases by 2013. Canada was well-positioned to be affected by the spread of the disease. As early as 2005, modeling published by researcher Nicholas Ogden, then at the University of Montreal, indicated that the geographic range of the Lyme-carrying tick could expand northward significantly due to climate change in this century.
Scientists long have anticipated that global warming would harm human health, and the most recent Intergovernmental Panel on Climate Change report highlights the risk for poor populations that don't have access to quality health care or other public services. For example, the risk of heat stroke is greatest in areas without access to power for air conditioning, and water-borne illnesses like cholera and intestinal viruses flourish in areas without safe drinking water.
But one of the clearest signs of the changing health risks in a warming world has emerged in two of the world's most advanced economies, the United States and Canada, as Lyme disease spreads in North America.
The U.S. Environmental Protection Agency this year added Lyme disease to its list of climate change indicators, a report meant to aid in public understanding of the effects of warming that scientists have been able to document....
'An emerging clinical problem'
The doctors presented their findings in April at an American College of Rheumatology symposium but declined to talk to The Daily Climate about their research until it is published in a medical journal. They are still working on finalizing their paper, an IWK Health Centre spokeswoman said. But in the abstract presented at that meeting, they called Lyme arthritis "an emerging clinical problem in Nova Scotia," with cases expected to continue to rise.
Untreated, Lyme disease can spread to joints, the nervous system, and even the heart. Heart block due to Lyme carditis can develop in minutes or hours, and is a rare but fatal complication. A more common problem that causes even greater concern in the health community: Lyme patients with symptoms persisting long after antibiotic treatment. There's great controversy over how long antibiotic treatment should be continued in such cases and who should bear the costs. The issue underscores the importance of early detection. "Almost always the persistent cases are in patients who were not treated early," said the CDC's Beard.
Robert Strang, Nova Scotia's chief public health officer, says one problem with diagnosis has been that Lyme involves "a lot of non-specific symptoms." Of the cluster of pediatric arthritis cases at IWK, he said, "that case series reminded us that there are joint and neurologic and cardiac ways that Lyme disease can present itself."...