It has been over six years since the COVID-19 pandemic began, and researchers are once again raising concerns: relatives of the SARS-CoV-2 virus are still circulating in animals, potentially waiting for an opportunity to infect humans. This time, the warning is backed by new evidence. Scientists from around the world have identified new members of the coronavirus family that are similar to SARS-CoV-2, and early laboratory tests indicate that some of these viruses can actually infect human cells.
New Research Findings
The study, recently published in the journal Cell, is the first major work of the Genotype to Phenotype Asia (G2P-Asia) Consortium, an international research collaboration formed as a continuation of the G2P-Japan Consortium. Led by Kei Sato from the Division of Systems Virology at The Institute of Medical Science, The University of Tokyo, the consortium worked with Chulalongkorn University to analyze bat samples from Thailand.
Discovery of Clade B Viruses
The researchers identified a new group of SARS-CoV-2-related viruses, which they have named Clade B. These viruses were found in acuminate horseshoe bats (Rhinolophus acuminatus) inhabiting an artificial cave in Thailand's Chachoengsao Province. Interestingly, a previously known group, Clade A, was also found co-circulating with Clade B, sometimes even infecting the same individual bat. The key difference between the two clades is that Clade B viruses can bind to the human ACE2 receptor, the same receptor that SARS-CoV-2 uses to enter human cells, while Clade A viruses cannot.
Potential for Human Infection
So far, there is no evidence that any of these viruses are spreading among humans. No outbreaks have been reported, and there is no immediate pandemic threat. However, scientists emphasize that the discovery is crucial for early detection. By identifying these viruses before they have a chance to spill over into humans, researchers can stay one step ahead. The findings highlight the importance of wildlife monitoring, which has been intensified since the COVID-19 pandemic.
Many of these discoveries come from stepped-up surveillance efforts across Asia and Africa, where scientists have been collecting samples from bats and other wild animals to map the diversity of coronaviruses in nature. This study focused on several SARS-CoV-2-like viruses found in bats, with particular attention to their spike proteins. The spike protein is the part of the virus that attaches to host cells, and if it can bind to human receptors, the virus may have the potential to infect humans.
Previous Evidence and Context
It is well known that bats are reservoirs for many coronaviruses. However, what is new and concerning is the proof that some of these viruses can already attach to human ACE2 receptors, particularly those in the lungs. Previous research published in Nature found bat coronaviruses in Laos that are only a few amino acids away from being nearly identical to SARS-CoV-2, and lab experiments showed they could infect human cells. Still, it is important to keep things in perspective: the ability to infect cells in a petri dish does not necessarily mean a virus can easily transmit between humans. Such a leap requires multiple mutations, the right environmental conditions, and a degree of chance. Nonetheless, the findings underscore that the animal kingdom harbors many viruses that are increasingly close to making the jump to humans.
Implications for Pandemic Preparedness
The discovery has reignited debates about the origins of COVID-19. While various theories circulate, most scientists agree that the virus likely originated from wildlife, particularly bats. As more close relatives of SARS-CoV-2 are found across Asia and beyond, the scale of the coronavirus universe becomes clearer. The World Health Organization continues to stress the importance of global surveillance, especially among wildlife. Recent studies, such as the discovery of a bat coronavirus (CcCoV-KY43) in the UK and Kenya that can bind to human lung receptors, show that some animal viruses are even more adaptable than previously thought.
For the general public, there is no immediate cause for panic. These are laboratory discoveries, not real-world outbreaks. However, they serve as a reminder that investing in monitoring, vaccine development, and treatment strategies for animal viruses is far more effective than scrambling for answers after a pandemic begins. Virologists warn that coronaviruses are particularly challenging because they mutate quickly, swap genetic material, and when multiple versions infect the same animal, they can combine to create entirely new and unpredictable threats.
