As the planet warms due to climate change, fears are growing among scientists that ancient disease-causing pathogens could be unleashed from the melting permafrost in the Arctic Circle.
Those fears are already being borne out. Just last August, in the tundra of the Yamalo-Nenets region of Siberia, nearly 100 people and 2,300 reindeer became infected with anthrax in the first outbreak there since 1941. One 12-year-old boy died.
Scientists believe the anthrax was released into the environment after being trapped in a long-frozen reindeer carcass that thawed during a summer-long heatwave.
Scientists have also discovered two viruses in the Siberian permafrost that were still infectious, even .
Thankfully, those viruses infect only amoebas and aren鈥檛 dangerous to humans. But that discovered the second virus noted "[the] fact that two different viruses retain their infectivity in prehistorical permafrost layers should be of concern in a context of global warming."
Dr. Stuart Harris, chief of the division of wilderness medicine at Massachusetts General Hospital, says it鈥檚 not unreasonable to think that more such outbreaks could happen as climate change brings warmth to soils that have been frozen for thousands of years.
He told CTV鈥檚 Your Morning on Tuesday that, given the thousands of hectares of ice that is covering 30,000 or 40,000 years of biologic history, 鈥渢he likelihood, if this melts, that you鈥檙e going to have something revealed would strike me as not trivial; it鈥檚 pretty high.鈥�
Harris says permafrost is a great preserver and 鈥渁cts like the best freezer you could have in your basement.鈥� It鈥檚 not only very cold, it鈥檚 continuously cold -- at least beneath the top few metres that melt and freeze with the season.
What鈥檚 more, the ice protects organisms and potential pathogens in ice that is preserved from ultraviolet light, which can break down DNA and RNA.
Harris said he wasn鈥檛 surprised to learn that anthrax managed to revive and spread, given that anthrax bacteria reproduce through spores, and spores are 鈥渞emarkably resistant鈥� and able to survive longer than average bacteria.
鈥淪o that is not at all surprising that it would be able to come back after 60, 80 or 100 years if it鈥檚 well-preserved,鈥� he said.
Other bacteria are more complex and fragile and may not survive as easily. But viruses, which are not organisms, can go dormant for years while waiting for a host cell to infect.
Harris says permafrost has proven to be a 鈥渞emarkably good preserver of biological specimens,鈥� which is why so many skeletons are found almost fully intact when the ice melts.
That鈥檚 good news if you鈥檙e looking to find bones and fossils of ancient animals, he says, 鈥�(but) it鈥檚 kind of scary if those ancient animals are harbouring pathogens that the human species has kind of forgotten about and can鈥檛 mount a good response against.鈥�
