I, For One, Welcome Our New Giant Viral Overlords
March 10, 2014
Increasing human contact with remote areas and species in Africa helped the AIDS virus leap the species barrier. Similarly, deadly hemorrhagic fevers like Ebola and Marburg have made the jump, seemingly aided by increasing development and commerce in remote African areas.
We expect that exotic viruses will occasionally emerge from Asia as novel organisms find pathways into increasingly large scale and mechanized animal husbandry.
Now we have a whole new vector.
French researchers who have revived a 30,000-year-old giant virus from a sample of Siberian permafrost are cautioning that the mining and drilling of northern regions could potentially free dormant pathogens out of the frozen soil.
“The thawing of permafrost either from global warming or industrial exploitation of circumpolar regions might not be exempt from future threats to human or animal health,” the researchers said in their paper published in this week’s Proceedings of the National Academy of Sciences.
“Our results … substantiate the possibility that infectious viral pathogens might be released from ancient permafrost layers exposed by thawing, mining, or drilling,” the paper said.
“What we’re trying to say is to be careful when you go into layers that haven’t been disturbed in several thousand or even millions of years. We risk digging up things we don’t necessarily want to see,” Dr. Abergel said by telephone from her office at Aix-Marseille University.
The risks are slim but “are more than theoretical since we have shown that we can reactivate a virus from such an ancient sample,” she said.
She noted that other researchers are already studying outbreaks of Siberian anthrax among domestic reindeer to see if they are linked to climate warming and the proximity of burial grounds of cattle that died from that spore a century ago.
Other scientists not involved in the research praised the French team for discovering the new virus, but were divided about the paper’s warning words.
Jacqueline Goordial, a permafrost microbiologist at McGill University, said the French team had found a simple, clever way to extract the Pithovirus.
“As for the pathogenicity, it is a definite possibility to be considered. … We do have evidence that cells can survive these long time scales … so it is a possibility that this could be of concern.”
Radiocarbon dating of the soil sample found that vegetation grew there more than 30,000 years ago, a time when mammoths and Neanderthals walked the Earth, according to a paper published in the US journal Proceedings of the National Academy of Sciences (PNAS).
P. sibericum is, on the scale of viruses, a giant. It has 500 genes, whereas the influenza virus has only eight.
It is the first in a new category of viral whoppers, a family known as Megaviridae, alongside two other categories that already exist.
The virus gets its name from “pithos,” the ancient Greek word for a jar, as it comes in an amphora shape.
At 1.5 millionths of a metre, it is so big it can be seen through an optical microscope, rather than a more powerful electron microscope.
Unlike the flu virus, though, P. sibericum is harmless to humans and animals, and only infects a type of amoeba called Acanthamoeba, the researchers said.
The work shows that viruses can survive being locked up in the permafrost for extremely long periods, France’s National Centre for Scientific Research (CNRS) said in a press statement.
“It has important implications for public-health risks in connection with exploiting mineral or energy resources in Arctic Circle regions that are becoming more and more accessible through global warming,” it said.