Jenni Gritters

Nov 6th 2020

Thawing Permafrost May Reawaken Dormant Diseases


During summer 2016, a 12-year-old boy in Siberia died from a puzzling disease linked to thawing permafrost. Scientific American reported that 20 other people in the same remote area were diagnosed with the same disease; another 80 were hospitalized with suspicious symptoms. Then, more than 2,300 reindeer were found dead because of this disease.

The cause? Anthrax.

Thawing Permafrost Releases Anthrax

Most Americans associate anthrax with a white, powdery substance used to poison other people via the mail. However, anthrax is an infectious disease caused by the bacterium bacillus anthracis. Anthrax is usually spread by contact with the bacterium’s spores, which often occur in infected animals. In the case of remote Siberia, scientists believe that the infection began in a reindeer that died 75 years ago, according to The Washington Post.

Scientific American warned that when permafrost — a permanently frozen layer of soil — begins to thaw because of the Earth’s changing temperatures, previously frozen spores that cause deadly diseases can be released into the air. These spores can get into the water and soil, and may eventually enter a community’s food supply.

In Siberia, a heatwave caused melting permafrost. Then came water and bubbling methane in the permafrost fields. Record fires lit up Russian grasslands, according to The Washington Post. The anthrax bacteria, which lay dormant and frozen for 75 years, thawed. Reindeer started to die. Reindeer herders fell ill. Eventually, the entire community found itself in quarantine.

Global Warming and Dormant Diseases

Scientific American noted that researchers have been predicting that warmer temperatures could cause permafrost to thaw, initiating a new spread of dormant diseases. When permafrost thaws, whatever is frozen also thaws, meaning ancient bacteria could be released into the environment more frequently as the Earth’s temperatures increase.

The release of these dormant diseases depends on how deeply the permafrost melts and how high temperatures go. It also depends on how strong the type of frozen bacteria is: some microorganisms can’t survive in the cold for very long, while others, like anthrax, seem built for long-term freezes.

Viruses also have the potential to survive for a long time in frozen Earth layers. It is possible, if not probable, that viruses that infected humans on a large scale (such as smallpox or the Spanish flu) could return. In 2014, two scientists resurrected the largest virus ever seen from a 30,000-year-old chunk of ice, according to Nature. The disease was still infectious, despite the time that had passed.

Cause for Concern?

Research published in Global Health Action warned that scientists should carefully monitor permafrost conditions, especially in areas where anthrax outbreaks have occurred in the past. Many scientists are doing just that. Janet Jansson of the Pacific Northwest National Laboratory uses molecular approaches to study the microbial communities that live in soil and sediments, specifically in permafrost. Paul F. Shuster and his team of scientists found significant stores of mercury in permafrost sites in Arctic regions, according to Geophysical Research Letters. In Woods Hole, Massachusetts, scientists are drilling into permafrost cores to see what they can find, hoping to offset the surprise release of new deadly diseases, said the New York Times.

Overall, the threat of thawing depends upon which microorganisms are unearthed. The risk of releasing dormant diseases also depends upon how warm our planet gets and how much our climate changes in the coming years. Heat waves could thaw permafrost more quickly than expected, so more research will be required before we are fully prepared.