Rabies and the Arctic Fox (Vulpes lagopus): A Review.

The Arctic fox (Vulpes lagopus) is the primary infection reservoir of Arctic rabies, the dynamics of which are poorly understood and subject to significant spatiotemporal variation. Although rabies presence has been documented in the region since the mid-19th century, there is currently no evidence of rabies impacting Arctic fox population size. Under the influence of climate change in a rapidly evolving Arctic ecosystem, alterations in transmission dynamics are predicted, with implications for this species. Concurrently, the World Health Organization leads the United Against Rabies collective in the aim of elimination of dog-mediated rabies by 2030, and although efforts have justifiably been directed to tropical regions, elimination will require a good understanding of rabies in the Arctic. Therefore, this review aimed to provide an overview of current Arctic rabies understanding, while identifying the key knowledge gaps. The review covered spatiotemporal trends in rabies populations, population dynamics of the host species, and current theories about Arctic rabies persistence. It is still unclear how Arctic rabies can persist under low host densities, which has led to several hypotheses in recent years. Creation of high animal density "hotspots" caused by heterogenic fox distribution and multispecies congregations in response to food availability, extensive Arctic fox migration patterns, and the potential evolution to a less lethal variant of rabies may all be part of the explanation. Evidence for these theories by using recent genetic and modeling studies was evaluated within the review. There is currently insufficient evidence about the efficacy and feasibility of vaccines against Arctic rabies. Key knowledge gaps need addressing to enable future control campaigns.