Prehistoric diseases laying dormant in ancient ice could soon be unleashed due to climate change.
Cities built on permafrost in Russia are now seeing temperatures which could destroy their infrastructure and result in anthrax poisoning.
In some parts of Russia, anthrax is known as the “Siberian plague”.
This is because the anthrax bacteria, which can occur naturally in the soil, has been killing livestock and people there for hundreds of years.
Anthrax and other deadly disease-causing bacteria can lie dormant in permafrost or ice and will only be released if melting occurs.
Permafrost is a thick layer of soil below the ground which has remained frozen for longer than two years.
Two-thirds of Russia's territory is permafrost, which can be hundreds of feet deep.
An anthrax poisoning event which occurred 70 years ago in the Arctic region of Yamal in Russia, has already been linked to rising temperatures.
This incident results in the deaths of an estimated 2,000 reindeer and the hospitalization of 96 people.
A 12-year-old boy also died at the time because he ate some venison infected with anthrax.
Experts at the time concluded that the "appearance of anthrax was stimulated by the activation of 'old' infection sites following anomalously high air temperature and the thawing of the sites to a depth beyond normal levels."
Ancient mass "cattle graves" dug deep into permafrost may be of increasing risk to life as temperatures rise and water running through these regions carries deadly bacteria to new areas.
The locations of these cattle graves are kept a secret but experts are calling for the potential spread of bacteria from these grave sites to human populations and livestock to be closely monitored.
Other old diseases such as smallpox and the Spanish flu could also be awoken in the warming temperatures.
Scientists also fear that the diseases could be spread all over the world due to craters in the Serbian permafrost known as frozen "methane bombs" which could erupt if they thaw.
Biologist Boris Kershengolts told the Telegraph: "If the area of these emissions overlaps with the burials of animals or humans who died from diseases in previous centuries, these spores and pathogens could spread over a huge area. It would be a disaster not just for the Arctic. The catastrophe could exceed Chernobyl.
This story originally appeared in The Sun.