Reindeer have not had an easy time recently. There are only about 600,000 left of them, down from 1.5 million in 2000 thanks to dwindling habitat due to climate change, and last August, 318 of those were struck by lightning in a single storm and killed.
Since last March, Norwegian officials have been keeping an eye out for cases of chronic wasting disease (CWD). The disease, which causes the brains of animals in the deer family, including moose and reindeer, to slowly turn to mush. It spreads through chemicals called prions, although scientists are not sure how exactly.
Prions are misshapen proteins that can cause other proteins—like vital ones in the brain—to change their shape, too. They’re found in the waste, saliva, and infected brain matter of diseased animals, and can stick around for years in the environment. Sometimes, the CWD-causing prions can form spontaneously brains of older animals, but in these cases the prions aren’t contagious.
Lab tests on the brains or excretions of animals have to confirm the presence of these prions. However, it’s easy to miss in most cases because it’s a degenerative disease that kills animals over time. Its symptoms include general health problems, like losing weight or drooling excessively, which could happen for any number of reasons.
According to Science, in 2016 officials found prions from CWD in the brains of two moose and three reindeer. The moose, they believe, likely developed the illness as result of old age, in which case prions would only be found in the brain and couldn’t spread to other animals. However, the reindeer all lived in the same herd in Nordfjella, a rocky region in the middle of the country.
Discovering three cases of CWD in dead reindeer likely means others in the herd are already sick, and potentially spreading prions to others. Although there’s never been a case of humans getting sick from CWD, we can contract a similar prion disease found in cattle—mad cow disease—from eating contaminated meat. Even if there’s no threat to human health, authorities are concerned that CWD could spread to other species and even across the globe through shipments of undiagnosed animals, or even prions that hitch a ride on human travelers.
For now, Norwegian park rangers will patrol the borders of the herd’s habitat to quarantine them until they have all been shot by amateur hunters. Reindeer won’t be allowed to live in the area until 2022 to ensure any leftover priors from current reindeer waste have broken down. Hopefully, the deaths of these reindeer will prevent the deaths of thousands more later on.