Spatio-temporal occurrence of rabies epizootics across Canadian Arctic, 1953-2014: from disease surveillance to ecological mechanisms

Rabies is endemic throughout the Arctic, and domestic dogs that have come in contact with rabid wild carnivores are the main source of rabies exposure for humans. Rabies is an ongoing public health concern for residents of... [ view full abstract ]

Rabies is endemic throughout the Arctic, and domestic dogs that have come in contact with rabid wild carnivores are the main source of rabies exposure for humans. Rabies is an ongoing public health concern for residents of northern communities, but little is known about the epidemiology of Arctic rabies. The aim of this study is to provide a descriptive overview of the spatio-temporal distribution of animal rabies cases across the Canadian Arctic and to explore the mechanisms underlying the onset of rabies outbreaks in the fox populations. In Canada, the Canadian Food Inspection Agency (CFIA) is responsible for rabies diagnostic testing of all wild and domestic animals suspected to be rabid and where there was a potential human or domestic animal exposure. The data collected through this surveillance system represent the largest and most comprehensive database of rabid animals across Canada, and provides unique information about spatio-temporal distribution of rabies cases in the Canadian Arctic. Here, we present an analysis of rabies cases collected in Yukon, Northwest Territories, Nunavut, Nunavik and Labrador from 1953 to 2014. Preliminary results show that rabies cases were found in all Arctic regions of Canada except Yukon, and were relatively synchronous among species. Nunavut seems to be an endemic region for Arctic rabies with an apparent 9-year cycle. This study provides the first portrait of rabies across the Canadian Arctic, and for the first time explores density and dispersal of fox populations as drivers in rabies transmission dynamics. Further analysis of these data in an epidemiological modelling context may allow us to better understand and predict the spatio-temporal dynamics of rabies occurrence in both wild and domestic carnivores, leading to better estimates of the varying risk of human exposure.