Scientists plan to reanimate a 30,000-year-old giant virus that has been found preserved in the frozen wastelands of Siberia, one of several pre-historic viruses to have been unearthed in the last 15 years. But while the researchers believe the finding will be of great scientific interest, they warned that the effects of climate change were likely to unearth more such microscopic pathogens, a reality which could pose an increased threat for the spread of disease.

Reporting this week in the flagship journal of the U.S. National Academy of Sciences, French researchers announced the discovery of Mollivirus sibericum, the fourth type of pre-historic virus found since 2003 — and the second by this team.

Before waking it, researchers will have to verify that the bug cannot cause animal or human disease. "A few viral particles that are still infectious may be enough, in the presence of a vulnerable host, to revive potentially pathogenic viruses," one of the lead researchers, Jean-Michel Claverie, told AFP.

To qualify as a "giant,” a virus has to be longer than half a micron, a thousandth of a millimeter or 0.00002 of an inch. Mollivirus sibericum — "soft virus from Siberia" — comes in at 0.6 microns, and was found in the permafrost of northeastern Russia.

Climate change is warming the Arctic and sub-Arctic regions at more than twice the global average, which means that permafrost is not so permanent any more.

The regions in which these giant microbes have been found are coveted for their mineral resources, especially oil, and will become increasingly accessible for people intent on industrial exploitation as more of the ice melts away.

"If we are not careful, and we industrialize these areas without putting safeguards in place, we run the risk of one day waking up viruses such as small pox that we thought were eradicated," Claverie added.

In safe laboratory conditions, Claverie and his colleagues will attempt to revive the newly discovered virus by placing it with single-cell amoeba, which will serve as its host.

Claverie, who runs a lab at France's National Centre for Scientific Research (CNRS), and a team discovered another giant virus, which they called Pithovirus sibericum, at the same location in 2013, then managed to revive it in a petri dish.

Unlike most viruses circulating today, and to the general astonishment of scientists, these ancient specimens dating from the last Ice Age are not only bigger, but also far more complex genetically than many.

Mollivirus sibericum has more than 500 genes, while another family of giant virus discovered in 2003, Pandoravirus, has 2,500. The Influenza A virus, by contrast, has eight genes.

In 2004, U.S. scientists resurrected the notorious Spanish flu virus, which killed tens of millions of people in 1918 to 1919, in order to understand how the pathogen was so virulent.

U.S. researchers then flew to Alaska to take frozen lung tissues from a woman who was buried in permafrost. By teasing genetic scraps out of these precious samples and from autopsy tissues stored in formalin, the team painstakingly reconstructed the code for the virus' eight genes.

The work was done in a top-security lab at the U.S. Centers for Disease Control and Prevention (CDC).

Al Jazeera and Agence France-Presse