By Gonzalo Lopez Sanchez
In 2014, a team of researchers from the French National Center for Scientific Research (CNRS) made a disturbing discovery deep in the permafrost in Siberia. About 30 meters above the surface, buried in the frozen ground, scientists detected the presence of a virus that had been inactivated for at least 30,000 years: Pithovirus sibericum. The worrying thing is that, back at the lab, the researchers verified that he was alive, and that he was capable of infecting his victims: amoebas.
But not all microorganisms that sleep on ice attack amoebas. American researchers found a 140,000-year-old plant pathogenic virus, and others managed to "revive" a harmless bacteria that had been trapped in ice for 750,000 years. There are also suspicions that the frozen carcasses of people and animals buried in the permafrost could be a haven for infectious agents from other times, such as the flu or smallpox.
In 2007, researchers found remains of the 1918 Spanish flu virus in the body of a woman who had died in the permafrost of Alaska 75 years ago, and this is believed to have happened at the end of last month, when Russian health authorities alerted of an outbreak of anthrax ("anthrax"), possibly originating from the carcass of a reindeer, in the Yamal region of Siberia. But anthrax is not the only threat.
"In 2012, a team of researchers found traces of smallpox in two 18th-century mummies," wrote Jean-Michel Claverie, a CNRS microbiologist and discoverer of the Phitovirus, in a review article. "If this virus were released into the environment, the consequences could be much more serious than this outbreak in Siberia."
Faced with anthrax, a disease associated with livestock in large areas of the world, a smallpox infection would mean the temporary return of a serious disease that has already been eradicated and that, in the 20th century alone, caused between 100 and 300 million deaths, according to the WHO . Opposite, it would have a population that is no longer vaccinated against it.
“Many viruses and many bacteria are stored in permafrost and survive there without problems. That is why there is a risk that when the soil thaws, the population will become infected with them, ”explained Felipe Gómez, a microbiologist at the Center for Astrobiology who investigates the ecology of this environment. But he does not think there are reasons to be alarmed: "It is a process that has already occurred in history, naturally, I do not expect great catastrophes."
For Bruno González-Zorn, director of the department of animal health of the veterinary faculty of the Complutense University of Madrid, the key to avoiding risks is to remain vigilant. “Ancient bacterial and viral pathogens will surely emerge, for which we are not prepared today, but they will also be pathogens that we have defeated in the past. I do not think they caused huge health alarms, but outbreaks that would be controlled quickly.
With the effects of climate change already visible in the Arctic, including a record year for Siberian temperatures, Jean-Michel Claverie believes there will be concern when the industry begins to access areas previously dominated by ice: “they are going to expose frozen soils for hundreds or thousands of years into the air, releasing the countless bacteria they contain.
Meanwhile, climate change threatens to spread tropical diseases, such as Zika, malaria or dengue, to temperate territories.
Microorganisms trapped in ice
A giant virus: Pithovirus sibericum
This giant virus infects amoebae and is harmless. Despite having been buried for 30,000 years, he was able to attack his victims in the laboratory.
Smallpox virus: Variola major
It was eradicated in 1979, but it is possible that it is present in the ice. "If this virus were released into the environment, the consequences could be much more serious than this outbreak in Siberia."
Enemy of plants: Tomato mosaic virus
This common tomato pathogen was able to survive buried in ice for 140,000 years.
Anthrax (“anthrax”), the threat in Siberia: Bacillus anthracis
It infects livestock and humans, and is spread through spores. These are very hardy and can survive on ice for decades.
The most fearsome flu: The 1918 Spanish flu virus
In 2007, researchers found remnants of the flu virus that killed 50 million people in the body of a woman who died in the permafrost of Alaska 75 years ago.