ABSTRACT
BACKGROUND: Investigations of rabid animals that cross provincial/territorial boundaries are resource intensive and complex because of their multi-jurisdictional and multi-sectoral nature. OBJECTIVE: To describe the multi-jurisdictional responses to two unrelated rabid puppies originating from Nunavut. METHODS: A descriptive summary of the investigations following the identification of a rabid puppy in Alberta (August 2013) and another in Saskatchewan (December 2014). RESULTS: These investigations involved public health and agriculture authorities in five provinces/territories, as well as the Canadian Food Inspection Agency (CFIA). In Alberta, a puppy who became ill after being transported by air from Nunavut was euthanized and diagnosed with rabies (Arctic fox variant). Eighteen individuals were assessed for exposure to rabies; nine received rabies post-exposure prophylaxis (RPEP). An exposed household dog that tested negative was electively euthanized. In Nunavut, the rabid puppy's mother and litter mates were placed under quarantine. In Saskatchewan, another puppy became ill during transit by air from Nunavut. It was subsequently euthanized and diagnosed with rabies (Arctic fox variant). Two of three Saskatchewan individuals, including a veterinary technician, received RPEP. Two Nova Scotia residents were exposed to the puppy while in Nunavut and received RPEP. One household dog received booster vaccination, was quarantined for 45 days and remained asymptomatic. In Nunavut, the rabid puppy's mother and litter mates were not identified. In both cases, exposure to an Arctic fox was the probable source of rabies in the puppies. CONCLUSION: Translocation of dogs from the north where Arctic fox rabies is endemic poses a risk to human and animal health and may negatively impact control of rabies in Canada. There is currently no national framework to prevent inter-jurisdictional movement of potentially rabid animals in Canada.
ABSTRACT
To form clinically evident metastases--the main cause of death in cancer patients--, tumor cells (TC) must complete a highly complex series of steps called the metastatic cascade, including local invasiveness, intravasation, circulation, adhesion and extravasation, survival, proliferation and angiogenesis. Since failure of any one of these steps results in metastatic failure, understanding the metastatic cascade may guide us to new therapeutic concepts. Here we review the role of specific TC adhesion and migration processes for organ-selective metastasis formation. TC adhesion in the microvasculature of host organs is a specific and highly regulated process mainly mediated by selectins for TC/endothelial cell binding and by integrins for TC/extracellular matrix interactions. Defined expression of the adhesion molecules and their corresponding ligands in the host organs and on the TC governs organ-selective non-random TC arrest. TC motility and subsequent chemotactically guided extravasation of adherent cells is the second rate-limiting step in organ-specific metastasis formation. Only if cells have completed adhesion and extravasation the growth of micrometastases and finally clinically evident metastases can occur.
