WORLD – SCIENCE
Scientists have found that ancient zombie viruses found in the permafrost can still infect living amoebas. This was reported by CNN, citing a study published in Viruses.
Permafrost covers a fifth of the Northern Hemisphere and has served as a kind of time capsule for thousands of years, preserving, in addition to ancient viruses, the mummified remains of a number of extinct animals that scientists have been able to discover and study in recent years.
The reason permafrost is a good storage area is not just because of the low temperatures; it is an oxygen-free environment, where light does not penetrate. However, temperatures in the Arctic are currently rising four times faster than in the rest of the planet, causing the top layer of permafrost in the region to thaw.
To better understand the dangers posed by frozen viruses, scientists are studying soil samples taken from the Siberian permafrost.
French Emeritus Professor of Medicine and Genomics Jean-Michel Claverie and his team have isolated several strains of ancient viruses from permafrost samples taken from seven different locations in Siberia.
These previously unknown strains represent five new virus families. The oldest of them, obtained from soil samples from the bottom of an underground lake, is nearly 48,500 years old. Younger samples, 27 000 years old, have been found in the remains of a woolly mammoth. It turned out that each was capable of infecting cultured amoeba cells.
Chances of spreading the virus
To date, scientists do not know how long these viruses, once in modern conditions, are able to maintain their ability to infect, or what the likelihood is that the virus will meet a suitable host.
In addition, not all viruses are disease-causing pathogens; some are benign or even beneficial to their hosts. Although the Arctic is home to 3.6 million people, it is still a rather sparsely populated area, making the risk of human exposure to ancient viruses very low.
Identifying viruses and other hazards contained in warming permafrost is the first step towards understanding the risks they pose to the Arctic. Other challenges include quantifying where, when, how fast and how deep the permafrost will thaw.
Thawing can be gradual, no more than a centimetre a decade, but it can also happen faster, such as in massive land slides, where deep and ancient layers of permafrost are suddenly exposed, releasing compounds and microorganisms that have not come into contact with living things for thousands of years.
According to scientists, the re-emergence of ancient micro-organisms could have unpredictable effects on soil composition and vegetation growth, and thereby further accelerate the effects of climate change.