The dirt beneath your feet might be hiding more than 50,000 kinds of viruses you never knew existed.
That's the finding from the largest-ever study of RNA viruses in cities around the world. Scientists from the University of Hawaiʻi at Mānoa, working with researchers globally, collected samples from soil, sediment, and other environments in nearly 100 cities across 30 countries. They discovered more than 55,000 RNA virus sequences—and about 80% of them had never been documented before.
While that number might sound scary, researchers say it should actually make people feel hopeful.
"I don't think the results of this study recognize increased risk," said Joshua Burkhart, an affiliate assistant professor at the John A. Burns School of Medicine at UH Mānoa. "Actually, I think it's a very hopeful message."
The study, published in the journal Nature Communications, aimed to create a baseline map of viruses already floating around in the places where people live and work. Knowing what's out there could help scientists spot unusual viral activity more quickly during future disease outbreaks.
"We can do viral surveillance," Burkhart said. "Work like this, if conducted more regularly, could help us get ahead of the next pandemic."
The researchers found roughly 60 viruses that computer models predict could infect humans, plus 47 that may infect other animals. They also identified 166 viruses that appear to interact with antibiotic-resistant bacteria known as ESKAPE pathogens—germs that cause thousands of hospital infections every year.
"One of the most surprising findings was that about half of all RNA viruses we found infect bacteria, not animals," Burkhart said. That contradicts a long-held belief that RNA viruses mostly target animals.
Soil and sediment samples showed especially high viral diversity, suggesting these environments deserve closer monitoring. While Hawaiʻi samples were collected for related research, they weren't included in this particular study—but Burkhart hopes future work will expand monitoring throughout the islands.
The team sees real practical potential in their findings. Those viruses interacting with antibiotic-resistant bacteria could point scientists toward entirely new ways of fighting infections.
"It opens a door," Burkhart said. "These viruses could open new avenues for us to develop new antibacterial agents."
For Burkhart, the takeaway is simple: better to map what's already there than to get caught flat-footed by what comes next.
"I don't think we can propose that we have an idea of the next pandemic," he said. "But this gives us tools to prepare."