Francesca Tomasi received her B.A. from the University of Chicago and currently does microbiology research.
In 2014, scientists revived a 30,000-year-old virus they found buried deep in the Siberian permafrost. Pithovirus sibericum was dormant for millennia, nestled about one hundred feet below the tundra, and it never posed a threat to humans. The virus only infects amoebae, and is part of a group known as giant viruses; its genome encodes at least 500 genes and the virus itself can be seen under a microscope, unlike most viruses (contrast this with Ebola, for instance, which encodes a mere 7 genes to carry out its infectious cycle). P. sibericum, along with other giant viruses, may hold clues to the origins of life on Earth – the fact that these viruses contain so much genetic material suggests to many scientists that they evolved from a cellular life form that no longer exists. That’s why the French and Russian team transplanted P. sibericum from its millennia-old permafrost home into a lab. Despite its thirty thousand-year lie-down, a feat that dwarfs Sleeping Beauty’s fabled siesta, the thawed virus successfully infected laboratory amoebae cultures, indicating that Siberian permafrost had served the exact same purpose as the artificial freezers researchers use to store biological samples for future use (and without the added costs of powering and maintaining large freezers 24/7).
Fast forward two years to another remote corner of Siberia. This time, instead of a controlled laboratory experiment, a heatwave is responsible for reactivating an old pathogen previously encased by protective permafrost. And instead of a harmless virus (to everything besides amoebae), this is a bacterium that still makes the US Department of Defense shudder due to its use as a bioterror weapon as recently as 2001. Bacillus anthracis is the causative agent of anthrax, a deadly disease that has affected humans and other animals across the globe. The main reservoir for anthrax is soil, but for the most part in the developed world naturally-occurring anthrax has not caused significant public health concern in decades.
Three quarters of a century ago, anthrax struck the Yamal Peninsula, a corner of Siberia that sits on top of the world, miles above the Arctic Circle. And despite the remoteness of the Yamal Peninsula, its ecology is teeming with organisms, including massive reindeer populations. Reindeer began dropping like flies as they contracted B. anthracis, their carcasses largely untouched after their death. Soon, it became just another anthrax outbreak for the books, its victims buried forever in frozen soil. Suddenly, in July 2016, Siberia saw a heatwave that began melting this permafrost. One fateful day saw the uncovering of a seventy-five-year-old reindeer corpse. Patient Zero was already dead, but it didn’t take long for thousands of living reindeer to become infected: anthrax forms environmentally robust spores, which quickly spread through the surrounding tundra, infecting unsuspecting grazers. Soon thereafter, human residents of the Yamal Peninsula began to get sick too. Russian officials have airlifted multiple families and hospitalized dozens of individuals. One child so far has died in the ongoing outbreak.
At the end of the 19th century, Siberia saw an outbreak of smallpox, one of history’s most nefarious killers. Few regions around the world (if any) have actually been fully spared of the virus’s grip. It is therefore no surprise that Siberia, despite its frigid winters and geographic isolation, faced its own slew of smallpox. The outbreak occurred along the Kolyma River, which runs along northeastern Siberia, and killed as much as 40 percent of the population of one particular town. The victims were buried along the Kolyma, eventually getting buried beneath thick layers of permafrost.
It is not unusual for thawing to occur during the summer in the Arctic Circle. Levels of thawing are usually between 30 and 40 centimeters, but increasing global temperatures have led to thawing as much as one meter deep. This includes thawing along the Kolyma River, and researchers have already uncovered corpses bearing the telltale sores of smallpox victims.
The effects of climate change on public health have been widely discussed over the last several years, as researchers warn about emerging and re-emerging pathogens. The events unfolding in Siberia – melting permafrost likely instigating an anthrax outbreak, smallpox-plagued corpses emerging from century-old burial grounds (so far, the virus itself has not been isolated from these bodies) – are providing a real-life manifestation of predictions and warning bells that have been sounding for years. There are two official (known) stocks of smallpox in the world: one at the CDC in Atlanta, Georgia, and another at the Vektor Institute in Novosibirsk, Russia. These stocks are tucked away in a small vial, frozen, at the bottom of a high-security freezer. In the words of the scientists who uncovered and studied P. sibericum in 2014, “Our results…substantiate the possibility that infectious viral pathogens might be released from ancient permafrost layers exposed by thawing, mining, or drilling.” Permafrost is just as good a freezer as the ones holding smallpox at the CDC or Vektor, if not better. In a world where the environment, humans, animals, and public health are becoming more inextricably connected every day, it is more than appropriate to caution against the very real threats posed by climate change and other environmental interventions. Just as infections (such as HIV and Ebola) have emerged from deep within the previously untouched rainforests of Africa, ancient or never-before-seen plagues may resurface from the melting permafrost of the Arctic Circle.