Could infectious threats capable of triggering pandemics emerge from the ice?

Once common, today only sporadic cases of anthrax occur in Europe and other parts of the world. However, the bacterium responsible for the disease, Bacillus anthracis, is capable of surviving for many years in the soil, enclosed within protective structures known as endospores. After ingesting them, an animal (in this case a reindeer) may develop a disease that is transmissible to humans.

The phenomenon was therefore attributed to the release of spores from the carcass of a reindeer that had died in 1941 and resurfaced from the ice or, more generally, from the ground, which had been softened by an unusual summer heatwave. Since then, no further cases of this kind have been reported, but rising global temperatures – which are increasing even more rapidly in the Arctic than in other parts of the world – could cause animal or human remains containing pathogens capable of triggering new epidemics, and not just anthrax, to resurface.

Among the infectious agents that require the closest monitoring is the human smallpox virus (Variola virus), which was declared eradicated from the planet in 1980. Again in Siberia – this time, however, during excavations at archaeological sites in the north-eastern regions – DNA fragments attributable to this virus were isolated in 2004 from a mummy exhibiting lesions consistent with the infection. Neither there nor elsewhere have whole, potentially infectious viral particles been found to date, let alone any cases of the disease, but the risk must not be underestimated. Stocks of smallpox vaccines do exist, but the capacity to produce huge quantities of the traditional vaccine in an emergency is currently limited, as reported by the World Health Organisation and a recent report by the National Academies of Sciences, Engineering and Medicine in the US. If necessary, new technologies would have to be utilised.

Outbreaks caused by influenza viruses are less likely, as their genetic material – RNA – is less stable than that of DNA viruses such as the smallpox virus. However, remnants of the virus responsible for the pandemic known as the ‘Spanish Flu’ have also been found in the ice. Between 1918 and 1919, the pandemic swept across every corner of the globe, and even the village of Brevig Mission in Alaska, with its 80 inhabitants, was decimated, with 72 deaths. Here, in the late 1990s, the body of an Inuit woman who had died almost 80 years earlier was exhumed from the permafrost in an excellent state of preservation; the virus’s genome was isolated from her lungs and sequenced. However, no intact virus particles capable of infecting and spreading between people were found.

Sometimes, to attract even more public attention by playing on people’s fears, scientists themselves coin terms from horror films, such as the term ‘zombie virus’, applied to giant particles (compared to the normal size of viruses, of course, but even larger than those of common bacteria), which, after 30–45,000 years of preservation in permafrost, have been shown to still be capable of infecting amoeba cells. In this case, what is more worrying than the size – which is irrelevant in terms of potential virulence for animals or humans – or the age of the particles, is the fact that a single group of researchers has found several different species in various locations across Siberia. If we were to look further, how many might we find?

There are also cases in which the threat posed by microorganisms emerging from the cold brings with it potential positive effects. For example, bacteria dating back some 5,000 years, recently discovered at the bottom of a frozen cave in Romania, have been found to be resistant to antibiotics and, at the same time, produce antimicrobial substances of their own. These could serve as a starting point for researching new medicines to combat other microorganisms that do not respond to the drugs currently available. On the one hand, two of the greatest threats of our time – the climate crisis and the phenomenon of antibiotic resistance – could therefore reinforce each other; but who knows, perhaps one might actually provide a solution to tackle the other.

Read the full factsheet on the dottoremaeveroche website run by Fnomceo