A virus that replicates readily in one bat species might fail entirely in another
Bats have long been understood as nature's most consequential viral reservoirs, yet the inner workings of their immunity have remained beyond scientific reach. A team of Korean researchers has now built a biological library — lab-grown miniature organs from five bat species and four organ types — that allows the world to observe, for the first time, how pandemic-capable viruses truly behave inside bat tissue. The achievement shifts the posture of pandemic science from reactive to anticipatory, offering a shared foundation from which humanity might recognize the next outbreak before it begins.
- Three-quarters of emerging human infectious diseases trace back to animals, and bats sit at the center of that risk — yet science has lacked the tools to study them with any real precision.
- Previous research was confined to single-species, single-organ approximations that left a vast and dangerous gap between laboratory observation and what actually happens inside a living bat.
- The new platform revealed that viruses behave in highly specific ways across different bat species and organs — a discovery that begins to explain both why some pathogens leap to humans and why bats themselves rarely fall ill.
- Two previously unknown bat viruses were isolated from wild feces; one could only be cultured in the new organoids, immediately validating the platform's power to detect what conventional methods cannot.
- The research team is now moving to build a global biobank that would let scientists worldwide screen novel viruses and test antivirals, directly supporting WHO pandemic prevention efforts.
Three-quarters of the infectious diseases to emerge in humans over recent decades originated in animals, and bats occupy a singular place in that story — natural reservoirs for the viruses behind COVID-19, MERS, influenza, and hantavirus. Yet despite their epidemiological importance, bats have remained largely opaque to science. Researchers lacked the tools to observe how viruses actually replicate inside bat tissue, move between organs, or why bats themselves seem immune to the pathogens they carry.
The work had long been constrained by crude approximations — generic cell samples or organoids derived from a single tropical fruit bat species, limited to one organ type. A virus might behave one way in a petri dish and entirely differently in living tissue, and the gap between laboratory observation and biological reality was substantial.
A team at the Institute for Basic Science in Korea has now built something far more complete: a biological library of bat tissue — organoids grown from five species across Asia and Europe, representing four organ systems including airways, lungs, kidneys, and small intestine. For the first time, researchers can observe how viruses like SARS-CoV-2, MERS-CoV, influenza A, and hantavirus infect bat tissue under conditions that closely mirror the living animal.
What they found was striking. Viral behavior proved far more specific than previously understood — a pathogen thriving in one species' lung tissue might fail entirely in another species' kidney. The platform also revealed that bat immune responses vary by both organ and species, offering a potential explanation for the long-standing paradox of how bats harbor so many dangerous viruses without becoming ill.
The platform's value was demonstrated immediately when the team isolated two previously unknown viruses from wild bat feces. One of them could not be grown using standard laboratory methods — it survived only in the new organoids. The researchers also adapted the system to rapidly screen antiviral drugs, including Remdesivir, with results more reliable than conventional cell cultures.
The vision now reaches beyond any single laboratory. Led by Dr. Choi Young Ki of the Korea Virus Research Institute, the team plans to expand the work into a global biobank — a shared resource for hunting novel bat viruses, assessing their pandemic potential, and testing candidate treatments. The platform marks a fundamental shift: from waiting for a virus to cause human disease, to watching for it before it ever does.
Three-quarters of the infectious diseases that have emerged in humans over the past few decades originated in animals. Bats occupy a particular place in this calculus—they are natural reservoirs for some of the most consequential viruses on earth, the ones responsible for COVID-19, MERS, seasonal influenza, and hantavirus. Yet for all their epidemiological importance, bats have remained largely opaque to scientific study. Researchers lacked the biological tools to observe how these viruses actually behave inside bat tissue, how they replicate, how they move between organs, or why bats themselves seem immune to the diseases they carry.
Until recently, the work had been constrained by crude approximations. Scientists either worked with generic cell samples or relied on organoids—lab-grown miniature organs—derived from a single species of tropical fruit bat, and even then, from only one organ type. The limitations were obvious. A virus might behave one way in a petri dish and entirely differently in living tissue. A pathogen that thrives in one species might fail to establish itself in another. The gap between what researchers could observe and what actually happened in nature was substantial.
A team based at the Institute for Basic Science in Korea, working with international partners, has now closed that gap. They have constructed what amounts to a biological library of bat tissue—organoids grown from five bat species distributed across Asia and Europe, representing four different organ systems: the airways, lungs, kidneys, and small intestine. The achievement is not merely incremental. For the first time, researchers can test how viruses like SARS-CoV-2, MERS-CoV, influenza A, and hantavirus actually infect bat tissue in conditions that closely approximate the living animal. Koo Bon-Kyoung, who directs the IBS Center for Genome Engineering, described the advance plainly: reconstructing bat organ physiology in the laboratory allows exploration of how zoonotic viruses operate with unprecedented precision.
What the team discovered was that viral behavior is far more specific than previously understood. A virus that replicates readily in one bat species' lung tissue might fail entirely in another species' kidney. This specificity—this narrow compatibility between pathogen and host—offers a window into why some viruses successfully jump to humans while others remain confined to their original animal hosts. The researchers also found that bat immune systems respond differently to the same virus depending on both the organ and the species involved. This may explain the paradox that has long puzzled virologists: how bats manage to harbor so many dangerous pathogens without becoming ill themselves.
The platform proved its worth immediately. The team isolated two previously unknown viruses directly from wild bat feces—a mammalian orthoreovirus and a paramyxovirus. Critically, one of these viruses could not be cultured using standard laboratory methods. It grew only in the new bat organoids. This single finding vindicated the entire enterprise. By converting the organoids into a two-dimensional format, the researchers were also able to rapidly screen potential antiviral drugs, including Remdesivir, with results more reliable than traditional cell culture methods could produce.
The vision now extends beyond the laboratory. The team, led by Dr. Choi Young Ki of the Korea Virus Research Institute, plans to expand this work into a global biobank—a shared resource that would allow scientists worldwide to systematically hunt for novel bat viruses, assess their pandemic potential, and test candidate drugs against them. Such a resource would support the genetic mapping of key bat species and feed directly into the pandemic preparedness efforts of organizations like the World Health Organization. The platform represents a shift from reactive response—waiting for a virus to emerge and cause human disease—to proactive surveillance and prevention. For the first time, scientists have a tool that allows them to study dangerous pathogens in conditions that mirror nature, safely and at scale.
Notable Quotes
Reconstructing bat organ physiology in the lab lets us explore how zoonotic viruses behave in unprecedented detail— Koo Bon-Kyoung, Director of the IBS Center for Genome Engineering
This platform lets us isolate viruses, study infections, and test drugs all within one system—something you can't do with ordinary lab cell models— Senior Researcher Kim Hyunjoon
The Hearth Conversation Another angle on the story
Why does it matter that we can now grow bat organs in the lab? Couldn't we just study the viruses in bats directly?
You could, but it's risky and impractical. These are some of the most dangerous viruses known. Growing them in controlled lab tissue lets us observe them without the biosafety hazards of working with live animals or infected tissue. We can also test hundreds of conditions quickly.
So the organoids are safer. But are they accurate? Does a lab-grown kidney really behave like a kidney inside a living bat?
That's the crucial question. The answer is: much more accurately than a petri dish does. An organoid has the three-dimensional structure, the cell types, the interactions between cells. It's not perfect, but it's close enough to reveal how viruses actually behave in tissue—which organs they prefer, which species they can infect.
The article mentions they found two viruses that couldn't grow in standard cultures. Why would that happen?
Standard cultures are usually just one or two cell types in a flat layer. Real tissue is complex—multiple cell types, three-dimensional architecture, immune cells present. Some viruses need that complexity to replicate. The organoids provide it.
And the global biobank idea—what would that actually do?
It would let researchers everywhere access standardized bat tissue from multiple species. Instead of each lab growing its own organoids, they'd have a shared resource. You could screen thousands of wild viruses against it, identify which ones pose pandemic risk, test drugs. It's pandemic early warning at scale.
Does this mean we'll never have another COVID-like surprise?
No. But it means we could potentially catch dangerous viruses before they jump to humans, or at least understand their pandemic potential much faster. It's not prevention—it's preparation.