Climate Change May Cause a Comeback of Historical Diseases

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by Helen Gloege ’23

Environmental Reporter

While many hope COVID-19 will be the only pandemic in their lifetime, recent research indicates that climate change may cause a comeback of several historical diseases.

The return of historical diseases may come from permafrost: ground that remains completely frozen at 32 F (0 C) or colder for at least two consecutive years. In many cases, permafrost has been frozen for tens of thousands — or even hundreds of thousands — of years. Permafrost includes rock, soil, sediments and varying amounts of ice that bind the elements together. Under a layer of soil, permafrost can be 3 to 4,900 feet thick and stores carbon-based remnants of plants and animals that were frozen before they could decompose. When permafrost warms and begins to thaw, it releases the stored carbon dioxide and methane into the atmosphere. This past summer, the Arctic experienced wildfires which caused additional permafrost to melt. 

Along with the risk of melting permafrost releasing carbon dioxide, it may also cause a resurgence of ancient disease-causing bacteria. The microorganisms that live in soil particles will have the ability to move toward the surface and thrive again in the environment outside the permafrost. Carcasses in the permafrost may also be infected with harmful pathogens.

Professor Jean-Michel Claverie and Chantal Abergel from Aix-Marseille University in France have been working with and studying viruses from permafrost. Claverie compares virus dormancy to seeds. When you put a seed in frozen soil for thousands of years, nothing happens to the seed, but when the soil warms and is no longer frozen, the seed will germinate. In the case of viruses, the same rules apply. 

There have been fragments of the 1918 influenza virus found in corpses in Alaska’s tundra, and smallpox and bubonic plague are likely buried in Siberia. Vectors of deadly infections of the 18th and 19th centuries may come back, especially in cemeteries where victims of infections have been buried. In the 1890s, there was a major epidemic of smallpox in Siberia that led to a 40 percent population loss. The victims from that incident are currently buried under the upper layer of permafrost.

In the 1990s, scientists from the State Research Center of Virology and Biotechnology in Novosibirsk tested remains of people from the Stone Age found in southern Siberia. While they didn’t find the virus itself, the scientists did find fragments of DNA. Later, in 2005, NASA scientists were able to revive bacteria that were located in a frozen pond in Alaska for 32,000 years. In 2007, scientists revived an 8 million-year-old bacteria as well as bacteria over 100,000 years old. In 2016, there was a large anthrax outbreak in Siberia that caused further curiosity about permafrost and viruses. It is believed that a heat wave in the Arctic thawed a layer of permafrost and reindeer carcasses containing anthrax warmed, causing the bacteria to thaw and anthrax to spread. Anthrax and other bacteria such as the one that causes botulism to form spores can then survive for extended periods of time. 

Increasing heat as a result of climate change isn’t the only environmental factor threatening the release of viruses. The Siberian north shore — now more accessible by sea — is being exploited through mining and drilling, which exposes ancient layers of permafrost.

Permafrost-caused viruses might not seem immediately problematic, as most viruses are inactive outside host cells and some viruses can’t survive long periods. However, there are exceptions. The idea that a virus can be eradicated gives a false sense of security. Bacteria that have been isolated and never come into contact with people or antibiotic drugs can, in some cases, produce antibiotic resistance and the human immune system wouldn’t be prepared.