title: Evolutionary aspects of emerging Lyme disease in Canada.
abstract: In North America, Lyme disease (LD) is a tick-borne zoonosis caused by the spirochete bacterium Borrelia burgdorferi sensu stricto, which is maintained by wildlife. Tick vectors and bacteria are currently spreading into Canada and causing increasing numbers of cases of LD in humans and raising a pressing need for public health responses. There is no vaccine, and LD prevention depends on knowing who is at risk and informing them how to protect themselves from infection. Recently, it was found in the United States that some strains of B. burgdorferi sensu stricto cause severe disease, whereas others cause mild, self-limiting disease. While many strains occurring in the United States also occur in Canada, strains in some parts of Canada are different from those in the United States. We therefore recognize a need to identify which strains specific to Canada can cause severe disease and to characterize their geographic distribution to determine which Canadians are particularly at risk. In this review, we summarize the history of emergence of LD in North America, our current knowledge of B. burgdorferi sensu stricto diversity, its intriguing origins in the ecology and evolution of the bacterium, and its importance for the epidemiology and clinical and laboratory diagnosis of LD. We propose methods for investigating associations between B. burgdorferi sensu stricto diversity, ecology, and pathogenicity and for developing predictive tools to guide public health interventions. We also highlight the emergence of B. burgdorferi sensu stricto in Canada as a unique opportunity for exploring the evolutionary aspects of tick-borne pathogen emergence.
authors: National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, Québec, Canada Groupe de recherche en épidémiologie des zoonoses et santé publique, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada Nicholas.ogden@phac-aspc.gc.ca.
authors: N H
authors: NH
authors: Ogden
authors: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom.
authors: E J
authors: EJ
authors: Feil
authors: Groupe de recherche en épidémiologie des zoonoses et santé publique, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
authors: P A
authors: PA
authors: Leighton
authors: National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.
authors: L R
authors: LR
authors: Lindsay
authors: Ludwig-Maximilians-Universität München, Department for Infectious Diseases and Zoonoses, Munich, Germany, and National Reference Centre for Borrelia and Bavarian Health and Food Safety Authority, Oberschleissheim, Germany.
authors: G
authors: G
authors: Margos
authors: Groupe de recherche en épidémiologie des zoonoses et santé publique, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
authors: S
authors: S
authors: Mechai
authors: National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, Québec, Canada Groupe de recherche en épidémiologie des zoonoses et santé publique, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
authors: P
authors: P
authors: Michel
authors: Faculties of Dentistry (Matrix Dynamics Group) and Medicine (Laboratory Medicine & Pathobiology), University of Toronto, Toronto, Ontario, Canada.
authors: T J
authors: TJ
authors: Moriarty
mesh_terms: D025065:Borrelia burgdorferi / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D002170:Canada / Q000453:epidemiology; D021821:Communicable Diseases, Emerging / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D008193:Lyme Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology* / Q000473:pathology; D009656:North America / Q000453:epidemiology; D058974:Phylogeography