Rabies outbreaks in the Canadian Arctic soon predictable? | Polarjournal
The population of Arctic foxes rises and falls with the availability of their prey. More voles and lemmings mean more foxes, which increases the likelihood of rabies spreading. Photo: Dr. Michael Wenger

Rabies outbreaks among Arctic foxes in the Canadian Arctic have occurred periodically for decades. The fluctuations in the frequency of the viral disease, which is practically always fatal, are closely related to the population fluctuations of lemmings and voles — the more prey available, the larger the fox population and the more rabies cases occur among them. The population in Arctic communities has become accustomed to this and generally knows how to deal with it. Still, scientists are working to develop a predictive model for future rabies outbreaks in Arctic Canada.

We recently reported that a large number of infected Arctic foxes had been identified in Nunavut this winter. Some reportedly showed up in several communities and attacked dogs. And, in the hamlet of Igloolik, a woman was reportedly bitten.

Speaking to Canadian news outlet Eye on the Arctic, Brian Stevens, wildlife pathologist with the Canadian Wildlife Health Cooperative, explained that it is “something that’s enzootic — so it’s always present in Arctic fox populations”. According to Stevens, local rabies outbreaks occur on a 10-to-15-year cycle.

Ben Kovic, a former conservation officer in Nunavut and former chair of the Nunavut Wildlife Management Board, put this winter’s rabies outbreak into perspective to Eye on the Arctic. He said he is not sure if the current outbreak is more severe than previous ones. Still, Stevens and other wildlife researchers suspect the population of Arctic foxes is booming this winter, leading to a greater spread of rabies.

Regardless of the magnitude of this year’s outbreak, many scientists are working to predict periodic peaks of infections in the future. Apart from prey population trends, researchers need to incorporate another aspect into their predictive models — climate change.

“Climate change is really going to affect the dynamics of rabies among Arctic foxes,” Dr. Emily Jenkins, a professor of veterinary microbiology at the University of Saskatchewan, told Eye on the Arctic.

Arctic foxes may not be able to migrate so freely and so far across sea ice in the future due to climate change. This would reduce the spread of rabies, but could lead to increased contact with humans and dogs. Photo: Dr. Michael Wenger

Normally, Arctic foxes roam the high Arctic in search of food, especially over sea ice, covering impressive distances. Dr. Jenkins hypothesizes that different fox populations could become more isolated as sea ice recedes and foxes can no longer move as freely or as far. This could reduce the overall spread of rabies.

On the other hand, foxes remain on land in greater numbers as sea ice disappears, increasing the likelihood that they will come into contact with humans and dogs.

Another aspect that complicates predictions about rabies in the Arctic is the northward advance of red foxes. The impact on Arctic foxes is not yet clear, but Dr. Jenkins suspects the arrival of the new competitor could have a detrimental effect. “Wild canids don’t tend to tolerate each other very well and they will compete for the same prey and they will actively kill each other,” she said.

Functioning predictive models would enable a kind of early warning system for rabies, allowing the public and communities to respond early by vaccinating dogs, for example. In addition, Dr. Jenkins is considering using bait to vaccinate Arctic foxes against rabies as well, similar to the way red foxes are vaccinated in Europe.

Development of the predictive models is underway; however, due to the Covid-19 pandemic, the researchers lack data from the past two years, during which they were unable to conduct the planned field seasons. “It means that we really lose some of our ability to track changes over time, which is, of course, one of the bigger questions about the Arctic, especially the western Canadian Arctic, which is undergoing climate change at about three times the rate of the global rate,” Dr Jenkins said.

Julia Hager, PolarJournal

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