Phylogeographic analysis of an Arctic rabies host species, the red (Vulpes vulpes) and arctic (Vulpes lagopus) fox, in the Eastern Subarctic region of Canada

Rabies is a fatal disease that raises public health concerns in the Canadian Eastern Subarctic region, however, the origins and the spread of epizootics of this lethal zoonotic disease are little understood. Coloured or red (Vulpes vulpes) and arctic (Vulpes lagopus) foxes across northern Canada are considered to be the principal maintenance or reservoir hosts of rabies virus. Therefore, I studied the phylogeography of one host, the red fox, to better understand the movement of the host and compare it with virus variant distribution across the landscape. Many studies confirm the impacts of environmental changes, particularly climate change, on the migratory behaviors of both fox and rabies virus variants. Also, different geographical areas have different population densities of red and arctic foxes. This study focused on red foxes sampled from the areas of Montreal, Abitibi-Témiscamingue, James Bay, Kuujjuarapik, Umiujaq, Inukjuak, and Kuujjuaq in Quebec, and Labrador City, North West River, Port Hope Simpson and Cartwright in Labrador. A series of 15-loci microsatellite profiles were used to genetically characterize 396 foxes and determine their phylogeographic relationships with respect to the landscape. Microsatellite markers were assessed using Micro-Checker to test for null alleles, stuttering or large allele dropout. Linkage disequilibrium among all pairs of loci was evaluated with GenePop. Genetic diversity and F-statistics was measured by using Arlequin in both loci and populations. Population structure was investigated with pairwise FST measures, Analysis of Molecular Variance, and individual clustering methods such as STRUCTURE and Geneland. FIT was significant at four loci and FST was significant at all loci indicating that the loci selected are suitable for analysis. FIS was not significant in any populations. The conclusions from the phylogeographic analysis were that there are four genetic groups of red foxes in this region of Canada, consisting of one in the Montreal area, one in James Bay, and two segregating in northern Quebec and Labrador. The Abitibi region was a mixture of the Montreal and the James Bay clusters. When a northwestern locality, Churchill NB, was included and 9-locus genotypes used, there were three distinct clusters, with Churchill dominated by one, Montreal by another and a third northeastern group prevalent in northern Quebec and Labrador. James Bay was a mixture of the Churchill cluster and the northeastern one, Abitibi- Témiscamingue was a mixture of the Montreal and the Churchill clusters, and the Churchill cluster also spread into northern Quebec and Labrador. These results suggest routes by which rabies virus could be spread via red fox movement patterns, such as along the coast, or from north to south, but also suggests a possible barrier to movement further south than Montreal. This study is important because the rabies virus is still a relevant public health concern for Canadians and, as such, research contributing to its effective eradication and control is of great importance. The results from this study will be used to inform theoretical models to help predict future rabies virus transmission and spread

Low levels of genetic differentiation and structure in red fox populations in Eastern Canada and implications for Arctic fox rabies propagation potential

Rabies is a lethal zoonosis present in most parts of the world which can be transmitted to humans through the bite from an infected mammalian reservoir host. The Arctic rabies virus variant (ARVV) persists mainly in populations of Arctic foxes (Vulpes lagopus), and to a lesser extent in red fox populations (Vulpes vulpes). Red foxes are thought to be responsible for sporadic southward movement waves of the ARVV outside the enzootic area of northern Canada. In this study, we wanted to investigate whether red foxes displayed notable levels of genetic structure across the Quebec-Labrador Peninsula, which includes portions of the provinces of Quebec and Newfoundland-Labrador in Canada, and is a region with a history of southward ARVV movement waves. We combined two datasets that were collected and genotyped using different protocols, totalling 675 red fox individuals across the whole region and genotyped across 13 microsatellite markers. We found two genetic clusters across the region, reflecting a latitudinal gradient, and characterized by low genetic differentiation. We also observed weak but significant isolation by distance, which seems to be marginally more important for females than for males. These findings suggest a general lack of resistance to movement in red fox populations across the Quebec-Labrador Peninsula, regardless of sex. Implications of these findings include additional support for the hypothesis of long-distance southward ARVV propagation through its red fox reservoir host