Although the ancient “giant virus” called a pithovirus found alive in the permafrost of Siberia does not pose a direct threat to humans (this time), the discovery of the virus by Jean-Michel Claverie and Chantal Abergel of Aix-Marseille University in Marseille, France is causing alarm in the science world.
Measuring a robust 1.5 microns in length, the giant virus is now the largest of its kind ever found and can be seen using only a regular microscope. The record was previously held by a virus named the pandoravirus that was discovered by the same Aix-Marseille University team.
What makes both the pithovirus and the pandoravirus so remarkable are the amount of genes found inside of them, with the pithovirus containing up to 500 genes, and the pandoravirus containing up to a whopping 2500. For comparison sake, the HIV virus contains only 12 genes in its make up.
According to National Geographic:
Amazingly, even after more than 30,000 years embedded in ancient permafrost, when Claverie and Abergel exposed amoebas in their lab to the virus, they found that the virus was still active and quickly infected the host cell. “We use amoeba on purpose as a safe bait for capturing viruses. We then immediately verify that they are not able to infect animal/human cells,” stressed the researchers.
Giant viruses are not just bigger but are hardier than others as well, said the researchers. This hardiness, along with a favorable environment, likely helped the newly discovered specimen stay intact for the thousands of years that it did. Viruses are often destroyed or rendered inactive by a number of factors, including light and biochemical degradation.
“Among known viruses, the giant viruses tend to be very tough, almost impossible to break open,” said Claverie and Abergel. “Special environments such as deep ocean sediments and permafrost are very good preservers of microbes [and viruses] because they are cold, anoxic [lacking oxygen], and in the dark.”
Although the discovery of this ancient virus causes no immediate human threat, the fact that an ancient virus was able to survive this long-buried in ice, raises questions about what other unknown viruses and pathogens dangerous to humans could be unearthed as climate change and land development break into these long-lost frozen viral time capsules.
The chance of an ancient killer virus making its way into the human population, although slim, is not completely out of the question.
“Mining and drilling means … digging through these ancient layers for the first time in millions of years. If ‘viable’ [viral particles] are still there, this is a good recipe for disaster,” said Claverie and Abergel.
But Edward Mocarski, a professor of microbiology at Emory University, says the risk of a virus pathogenic to humans being released from the ice is very small.
“The idea would make a great movie but is extremely unlikely unless the virus came from a frozen human being who possibly died from a virus that is no longer in circulation,” said Mocarski when contacted via email.
“A very small proportion [of the viruses on Earth] represent viruses that can infect mammals and an even smaller proportion pose any risk to humans.”
University of Nebraska’s Van Etten agreed that such a situation was unlikely but possible with the right conditions.
“The biggest source of genes on the planet is probably from viruses, and they’re just everywhere, but in general they’re highly specific for the organisms that they grow in,” said Van Etten.
But hey, let’s all just continue to ignore climate change and that whole pesky global warming topic, because it’s not like anything bad could happen. Right?