Can infectious threats capable of triggering pandemics arrive from the ice?

Once frequent, today only sporadic cases of anthrax (also known as 'anthrax') occur in Europe and other parts of the world. However, the bacterium responsible for the disease, Bacillus anthracis, has the ability to preserve itself for many years in the soil, within protective structures called endospores. After ingesting these, an animal (in this case the reindeer) can develop a disease that can be transmitted to humans.

The phenomenon was then attributed to the release of spores from a dead reindeer carcass in 1941 that resurfaced from the ice or, more generally, from the ground, softened by an abnormal summer heat wave. Since then, no such cases have been reported, but the increase in the planet's temperature - which in Arctic areas is proceeding even faster than in other parts of the globe - could lead to the resurfacing of animal or human remains containing germs capable of triggering new epidemics, and not only of anthrax.

Among the infectious agents on which closer surveillance must be maintained is the human smallpox virus (Variola virus), declared eradicated from the planet in 1980. Also in Siberia - this time, however, by excavating archaeological sites in the north-east - DNA fragments traceable to this virus were isolated in 2004 from a mummy that had lesions compatible with infection. Neither there nor anywhere else to date have whole, potentially infectious virus particles been found, let alone cases of disease, but the risk should not be underestimated. There are stocks of smallpox vaccines, but the capacity to produce huge quantities of conventional vaccine in an emergency is currently limited, as reported by the World Health Organisation and a recent report by the US National Academies of Sciences, Engineering and Medicine. In the event, new technologies would have to be used.

Less likely are outbreaks from influenza viruses, whose genetic material, RNA, is less resistant than DNA viruses such as smallpox. However, remnants of the pandemic influenza virus known as 'Spanish flu' have also emerged from the ice. Between 1918 and 1919, the scourge reached every corner of the earth, and even the village of Brevig Mission, Alaska, with its 80 inhabitants, had been 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, from whose lungs the virus genome was isolated and sequenced. However, whole virus particles, capable of infecting and transmitting between people, were not found.

Sometimes, in order to arouse even more public attention by playing on fear, scientists themselves coin horror-movie expressions, such as the term 'zombie virus', attributed 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 storage in the permafrost, have shown that they can still infect amoeba cells. In this case, more than the size - irrelevant to potential virulence for animals or humans - or the antiquity of the particles, it is of concern that a single group of researchers found several species in different locations in Siberia. If more were searched, how many could we find?

There are also cases where the threat of microorganisms emerging from the cold brings with it potential positive effects. For example, bacteria some 5,000 years old that were recently discovered at the bottom of an icy cave in Romania are proving to be resistant to antibiotics and, at the same time, are themselves producing antimicrobial substances. These could be used as a starting point to study new drugs against other microorganisms that do not respond to the drugs available to us. On the one hand, two of the worst threats of our time, the climate crisis and the phenomenon of antibiotic resistance, could thus be mutually reinforcing, but who knows, maybe from one will come help in tackling the other.

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