Discover how scientists isolated SARS-related coronaviruses from animals in Southern China and what this reveals about pandemic prevention.
Imagine a bustling market in Southern China, filled with the sounds and smells of various wild animals. Amidst the cages holding Himalayan palm civets, raccoon dogs, and ferret badgers, something invisible was lurking—a virus that would soon captivate the world's attention. This is where the story of SARS begins, not in hospitals, but in the vibrant ecosystem of a live-animal market. The discovery of viruses closely related to the SARS coronavirus in these animals marked a pivotal moment in our understanding of how dangerous pathogens emerge from wildlife to threaten human global health 1 9 .
For years, scientists had suspected that the SARS coronavirus, which caused the 2003 outbreak that spread to 28 countries, originated from animals. But the crucial evidence came when researchers decided to investigate the markets where various wild animals were housed in close proximity. What they found revolutionized our understanding of disease emergence and revealed the intricate dance between animal viruses and human populations 9 .
This article will take you through the fascinating science behind the isolation and characterization of SARS-related coronaviruses from animals in Southern China. We'll explore the key experiments that uncovered these viruses, examine what makes them tick, and consider what this means for our ongoing battle against emerging infectious diseases.
Coronaviruses are a large family of viruses known for their distinctive crown-like appearance when viewed under an electron microscope—hence the name "corona," which means crown in Latin. They're single-stranded RNA viruses that can infect a wide range of animals, from birds to mammals, including humans 7 .
Zoonotic diseases are infections that naturally spread from animals to humans, and they've played a significant role throughout human history. Approximately 6 out of 10 known infectious diseases in people have a zoonotic origin 7 .
| Disease | Animal Origin | Key Features |
|---|---|---|
| Bubonic Plague | Rodents (via fleas) | Caused 50 million deaths in 14th century Europe 7 |
| Rabies | Various mammals | Nearly 100% fatal once symptoms appear; vaccine available 7 |
| HIV/AIDS | Chimpanzees | Has killed more than 25 million people 7 |
| SARS | Bats (via civets) | First severe transmissible disease of 21st century 8 |
| COVID-19 | Bats (likely via intermediate host) | Global pandemic with millions of deaths 7 |
Why invest time and resources in looking for viruses in animals before they cause human outbreaks? The answer lies in the concept of pandemic prevention. By identifying potentially dangerous viruses in animal populations, scientists can develop tools—like diagnostic tests, treatments, and vaccines—that might be deployed rapidly if a spillover event occurs 2 .
As Dr. Amira Roess, a professor of global health and epidemiology, explains: "It helps us understand what happens in the event that this does spill over and pose a risk. It's good to get ahead of that. The more we know about these viruses, the better" 2 .
In 2003, as SARS was spreading across the globe, a team of scientists made a crucial decision: they would investigate the live-animal markets of Guangdong Province, China, where some of the earliest human cases had been reported. Their groundbreaking work would reveal the animal origins of SARS and transform our understanding of emerging infectious diseases 1 9 .
Using swabs, they collected nasal and fecal samples from the animals, preserving them in a special medium with bovine serum albumin and antibiotics 9 .
The samples were tested for SARS coronavirus nucleic acid using reverse transcription-polymerase chain reaction (RT-PCR) 9 .
Specimens were inoculated into FRhK-4 cells to detect live, infectious virus through visible cytopathic effect 9 .
Once viruses were isolated, researchers sequenced their entire genomes to understand their relationship to the SARS coronavirus found in humans 9 .
Blood samples from both animals and humans working in the markets were tested for antibodies to the novel virus, indicating previous infection 9 .
The findings were striking. The researchers detected SARS-like coronaviruses in several animals:
Perhaps most importantly, when the researchers tested humans working at the market, they found that 40% of wild-animal traders and 20% of animal slaughterers had antibodies to the virus, compared to only 5% of vegetable traders. This provided compelling evidence that people with greater exposure to these animals were being infected with the virus 9 .
Genetic analysis revealed that the animal viruses were 99.8% identical to human SARS coronavirus, confirming their close relationship. However, the animal viruses contained a distinctive 29-nucleotide sequence not present in most human SARS viruses 1 9 .
| Animal Species | Virus Detected by RT-PCR | Virus Isolation | Antibodies Present |
|---|---|---|---|
| Himalayan palm civet | 4 of 6 animals | 2 of 6 animals | 3 of 4 animals tested |
| Raccoon dog | 1 of 1 animal | 1 of 1 animal | 1 of 1 animal |
| Chinese ferret badger | 0 of 1 animal | 0 of 1 animal | 1 of 1 animal |
| Beaver | 0 of 3 animals | 0 of 3 animals | Not reported |
| Chinese hare | 0 of 4 animals | 0 of 4 animals | Not reported |
As the researchers noted in their publication: "Our findings suggest that the markets provide a venue for the animal SCoV-like viruses to amplify and to be transmitted to new hosts, including humans, and this is critically important from the point of view of public health" 9 .
Virology research relies on specialized tools and techniques to isolate, identify, and characterize viruses. Here are some of the essential components of the coronavirus researcher's toolkit:
Detects viral genetic material. Identified SARS-like viruses in animal swab samples 9 .
Measures infectious virus quantity. Determined viral titers and infection efficiency in different cell types 4 .
Detects protective antibodies. Measured immune response in animals and humans exposed to SARS-like viruses 9 .
Determines complete genetic code. Revealed evolutionary relationships between animal and human coronaviruses 9 .
These tools have been essential not only for understanding SARS but also for responding to COVID-19. The techniques developed during the SARS outbreak provided a head start when SARS-CoV-2 emerged in 2019 4 .
The work that began with SARS continues today, with scientists regularly discovering new coronaviruses in animal populations. In early 2025, researchers at the Wuhan Institute of Virology identified another bat coronavirus, named HKU5-CoV-2, that can enter human cells using the same ACE2 receptor as SARS-CoV-2 2 6 .
The interconnectedness of human, animal, and environmental health has led to the adoption of a "One Health" framework. As demonstrated by the CDC's efforts, this approach brings together public health, animal health, and environmental health experts to collaborate on disease surveillance and response 3 .
The OH-FICC Group, for instance, includes representatives from more than 20 federal agencies who coordinate on COVID-19 issues at the human-animal-environment interface 3 .
The isolation and characterization of SARS-related coronaviruses from animals have directly informed our pandemic preparedness strategies:
As Dr. Alex Greninger from the University of Washington Medical Center notes: "There are probably a lot of coronaviruses circulating in bats that can enter human cells" 2 . This reality makes the work of virus discovery and characterization more urgent than ever.
The discovery of SARS-related coronaviruses in animals in Southern China represents a triumph of scientific detective work. What began with swabs from civets and raccoon dogs in a bustling market has grown into a comprehensive understanding of how viruses move between species and sometimes pose grave threats to human health.
The critical importance of surveillance at the human-animal interface
The value of international scientific collaboration
The need for a One Health approach to disease prevention
While the COVID-19 pandemic has made the world acutely aware of coronavirus threats, it's crucial to maintain perspective. As Dr. Phoebe Lostroh, a virologist and author, reminds us: "I think we ought to be a lot more worried about problems like avian flu and its impact on cows and kitties and all sorts of other mammals than this new coronavirus..." 2 . The key is balanced vigilance—respecting wildlife as potential sources of pathogens while recognizing that most animal viruses will not cause human pandemics.
The next time you hear about a new virus discovered in bats, civets, or other wildlife, remember the dedicated scientists working to understand these pathogens before they become global threats. Their work in the markets and laboratories represents our first line of defense against future emerging diseases.