When a new zombie virus discovered due to permafrost melting made its way into headlines in March 2023, it caused concern. Some wondered if this meant we were on the brink of another worldwide health crisis. Here's a look at what researchers have brought back from the (near) dead, and how this undead infection could relate to public health.
What Is a Zombie Virus?
A zombie virus is a virus frozen in time. They're often caught up in permafrost after hitching a ride in the immune system of a long-deceased animal or insect. If these viruses are thawed out and introduced into a suitable host, however, they can effectively resurrect and get back to doing what they do best: infecting organisms.
According to Scientific American, zombie virus genomes could play a positive role in disease treatment. These genomes are byproducts of viral infections that are no longer capable of reproducing on their own. If they're introduced to cells compromised by other infections, they can hijack existing viruses and use them to replicate, in effect reducing the overall viral load. In healthy cells, meanwhile, these zombies have no effect. While research on zombie virus benefits remains in the early stages, the work suggests that not all zombies are out for brains.
Playing the Long Game: A Virus Threat 48,500 Years in the Making
How long can a virus survive and then be brought back to life in melting permafrost? If you said 50,000 years, you were just 1,500 years off the mark.
This is because permafrost offers the ideal environment to keep viruses in stasis. Not only is the temperature cold, but it's also oxygen-free and doesn't let in light. In other words, the energy sources needed to help the virus replicate — or kill it completely — are absent in permafrost.
As climate change drives rising temperatures, however, the top layers of permafrost are beginning to melt. This has made it possible for researchers like Jean-Michel Claverie, Emeritus professor of genomics at the School of Medicine of Aix-Marseille University, to obtain and revive virus samples that are tens of thousands of years old. Most recently, he discovered five new families of viruses in samples ranging from 48,500 years old and found in the soil of an underground lake to those discovered in a 27,000-year-old wooly mammoth's stomach contents and coat.
The biggest threat posed by these viruses? A lack of natural human immunity. Since we've never encountered these viruses, our immune systems have no natural defense against their infection vectors. As a result, it's possible that these old issues could become modern problems. This isn't without precedent: Consider the impact of the European colonization of the Americas, which led to massive outbreaks of diseases, such as smallpox and influenza.
Is Permafrost Melting a Public Health Risk?
Yes and no. So far, the viruses reanimated by scientists are only capable of infecting amoebas. While it's possible that less-permanent permafrost could bring human- and animal-infecting viruses back to life, Claverie notes that any unearthed microbes would be "quick to decay once they're exposed to heat, UV light and oxygen." Claverie also points out that, while humans might lack the inherent ability to combat zombie infections, the chance of infection itself is "extremely low" because these viruses have never encountered a modern human immune system.
While the chances of a zombie virus going viral are slim, however, they're never zero. Increasing temperatures mean that more permafrost is melting more quickly, which means that more zombie viruses are getting a second shot. As the COVID-19 pandemic made perfectly clear, it doesn't take much for a new virus to spread once it successfully infects an immune system that lacks effective defenses.
In short, while the new zombie virus discovered doesn't spell disaster for humankind, it does speak to the second-order effects of climate change. If we're not careful, crop and coastline loss could be the precursors to an unopposed, undead viral vector.
Are you interested in science and innovation? We are, too. Learn more about our people and life at Northrop Grumman, or check out our career opportunities to see how you can be a part of defining possible.