Parasite ecology, evolution and population genetics: the evolutionary ecology of epidemiological triangles

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There is a lack of knowledge regarding the evolutionary ecology of vector-borne diseases, that is, the ecological and historical interactions, and changes in the population genetic structure of the three groups of organisms that make up an 'epidemiological triangle'; vectors (e.g. mosquitoes & ticks), hosts (vertebrates), and pathogens (e.g., bacteria & viruses) transmitted by vectors to hosts. Ticks are the most important reservoirs and vectors of human infectious diseases in North America, and they are responsible for transmitting pathogenic agents to domestic animals and wildlife. There are over 30 tick species that occur in Canada, yet for many species, we know very little of the types (i.e. species and strains) of bacteria they contain. Over the next 5 years, graduate and undergraduate students in my research group will conduct innovative and exciting research projects on the population genetics and coevolution of organisms in epidemiological triangles, in which the vectors are different species of tick that differ in their life cycles, types of hosts used and/or their relative host specificity. Molecular techniques will be used to quantify the population genetics of ticks, bacteria and small mammals for multiple genetic markers. Spatial and temporal changes in the genetic structure of tick populations and of different bacterial strains will also be explored. Detailed knowledge of the population genetics and coevolutionary relationships of ticks, their bacteria and hosts, permits an understanding of anomalies in the epidemiology of vector-borne diseases, which might otherwise go explained. Our findings will provide key insights into the ecological and evolutionary factors influencing the population genetic structure of epidemiological triangles, and provide critical information for the construction of ecological epidemiological models of microbial transmission and the population dynamics of vector-borne diseases. Such work is also of importance because some tick species are expanding their geographical ranges in Canada, which poses an increased threat to human and animal health.