Comparison of the ticks and tick-borne bacteria of small mammals in Western Canada
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Ticks are important vectors of pathogenic agents that cause disease in humans, domestic animals, and wildlife. They are also hosts for a variety of bacterial endosymbionts. However, little is known about the microbial diversity of many tick species, particularly those species that parasitize small mammals in western Canada. In this thesis, I used a combined morphological and molecular approach to identify, to the species-level, ticks that parasitized small mammals from three localities in Saskatchewan and British Columbia. The genetic diversity and phylogenetic relationships of these tick species was also examined. Comparisons were also made of the composition and diversity of bacteria within individuals of each tick species. Questions relating to the biology, systematics, and vector ecology of the vole tick (Ixodes angustus), the rotund tick (Ixodes kingi), the sculptured tick (Ixodes sculptus) and the Rocky Mountain wood tick (Dermacentor andersoni) were also addressed. The results of my thesis work revealed that I. kingi and I. sculptus were the most encountered tick species on northern pocket gophers (Thomomys talpoides) and Richardson’s ground squirrels (Spermophilus richardsonii), respectively, in Saskatchewan, while I. angustus was the most abundant tick on red-backed voles (Clethrionomys gapperi) in Kootenay National Park (British Columbia). At least 40 genera of bacteria were detected in the four tick species; however, there were significant differences in the composition of the bacteria among tick species. Two novel species of Rickettsia and three putative new species of Rickettsiella were also discovered. The findings of this thesis make an important contribution to our understanding of the evolution and ecology of ticks and tick-borne bacteria.
DegreeDoctor of Philosophy (Ph.D.)
SupervisorChilton, Neil B.
CommitteeCota-Sanchez, Hugo; Neal, Dick; Hwang, Yeen-Ten
Copyright DateJuly 2013
ticks, bacteria, small mammals, Western Canada