title: Different Ecological Niches for Ticks of Public Health Significance in Canada.
abstract: Tick-borne diseases are a growing public health concern as their incidence and range have increased in recent decades. Lyme disease is an emerging infectious disease in Canada due to northward expansion of the geographic range of Ixodes scapularis, the principal tick vector for the Lyme disease agent Borrelia burgdorferi, into central and eastern Canada. In this study the geographical distributions of Ixodid ticks, including I. scapularis, and environmental factors associated with their occurrence were investigated in New Brunswick, Canada, where few I. scapularis populations have been found to date. Density of host-seeking ticks was evaluated by drag sampling of woodland habitats in a total of 159 sites. Ixodes scapularis ticks (n = 5) were found on four sites, Ixodes muris (n = 1) on one site and Haemaphysalis leporispalustris (n = 243) on 41 sites. One of four adult I. scapularis ticks collected was PCR-positive for B. burgdorferi. No environmental variables were significantly associated with the presence of I. scapularis although comparisons with surveillance data in neighbouring provinces (Québec and Nova Scotia) suggested that temperature conditions may be too cold for I. scapularis (< 2800 annual degree days above 0°C [DD > 0°C]) across much of New Brunswick. In contrast, the presence of H. leporispalustris, which is a competent vector of tularaemia, was significantly (P < 0.05) associated with specific ranges of mean DD > 0°C, mean annual precipitation, percentage of clay in site soil, elevation and season in a multivariable logistic regression model. With the exception of some localized areas, temperature conditions and deer density may be too low for the establishment of I. scapularis and Lyme disease risk areas in New Brunswick, while environmental conditions were suitable for H. leporispalustris at many sites. These findings indicate differing ecological niches for two tick species of public health significance.
authors.affiliation: Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Gabriele-Rivet
authors.affiliation: Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada; Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Arsenault
authors.affiliation: Office of the Chief Medical Officer of Health, New Brunswick Department of Health, Fredericton, New Brunswick, Canada.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Badcock
authors.affiliation: Environment Canada, Ottawa, Ontario, Canada.
authors.forename: Angela
authors.initials: A
authors.lastname: Cheng
authors.affiliation: Jim Edsall Insect Identification Services, Dartmouth, Nova Scotia, Canada.
authors.forename: Jim
authors.initials: J
authors.lastname: Edsall
authors.affiliation: New Brunswick Department of Aquaculture, Agriculture & Food, Fredericton, New Brunswick, Canada.
authors.forename: Jim
authors.initials: J
authors.lastname: Goltz
authors.affiliation: New Brunswick Natural Resources, Fredericton, New Brunswick, Canada.
authors.forename: Joe
authors.initials: J
authors.lastname: Kennedy
authors.affiliation: Public Health Agency of Canada, National Microbiology Laboratory, Winnipeg, Manitoba, Canada.
authors.forename: L Robbin
authors.initials: LR
authors.lastname: Lindsay
authors.affiliation: Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Saint-Hyacinthe, Québec, Canada.
authors.forename: Yann
authors.initials: Y
authors.lastname: Pelcat
authors.affiliation: Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada; Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Saint-Hyacinthe, Québec, Canada.
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Ogden
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology / Q000502:physiology*; D025065:Borrelia burgdorferi / Q000235:genetics / Q000302:isolation & purification; D002170:Canada; D017753:Ecosystem; D018884:Ixodes / Q000382:microbiology / Q000502:physiology*; D008193:Lyme Disease / Q000635:transmission*