New Bat Coronavirus Discovered in China: Assessing the Potential Human Threat

Chinese researchers have identified a novel bat coronavirus, designated HKU5-CoV-2, which exhibits the capability to infect human cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. This discovery has prompted discussions within the scientific community regarding the potential for cross-species transmission and the implications for public health. The research, led by virologist Dr. Shi Zhengli, involved collaboration among scientists from the Guangzhou Laboratory, Guangzhou Academy of Sciences, Wuhan University, and the Wuhan Institute of Virology. Their findings were published in the peer-reviewed journal Cell on February 18, 2025. The study reports that HKU5-CoV-2, a member of the merbecovirus subgenus—which includes the Middle East respiratory syndrome coronavirus (MERS-CoV)—can utilize not only bat ACE2 receptors but also human ACE2 and those of various other mammals. This receptor usage is significant because ACE2 serves as the entry point for several coronaviruses into host cells. The identification of HKU5-CoV-2 traces back to surveillance efforts in bat populations, particularly the Japanese pipistrelle bats in Hong Kong, where the original HKU5 strain was first detected. The newly discovered lineage, HKU5-CoV-2, was isolated from bat samples and demonstrated the ability to infect human cells in vitro. However, the researchers emphasize that the efficiency of HKU5-CoV-2 in binding to human ACE2 is significantly lower than that of SARS-CoV-2, the virus responsible for the COVID-19 pandemic. This reduced binding affinity suggests a lower potential for human infection under natural conditions. Despite the lower binding efficiency, the study highlights the importance of monitoring bat coronaviruses due to their potential to adapt and cross species barriers. The researchers caution against exaggerating the immediate threat posed by HKU5-CoV-2 but advocate for continued surveillance and research to understand its evolution and potential risks. They note that bat merbecoviruses, such as HKU5-CoV-2, pose a risk of spillover to humans, either through direct transmission or via intermediate hosts. The World Health Organization (WHO) has recognized the significance of such pathogens by including merbecoviruses on its list of emerging pathogens that require urgent attention for pandemic preparedness. This inclusion underscores the necessity for global collaboration in monitoring and researching zoonotic viruses to preempt potential outbreaks. Dr. Shi Zhengli, often referred to as "Batwoman" for her extensive work on bat-derived viruses, has been a central figure in coronavirus research. Her team’s discovery of HKU5-CoV-2 adds to the growing body of evidence that bats serve as natural reservoirs for a variety of coronaviruses, some of which have the potential to infect humans. Understanding the mechanisms that allow these viruses to jump between species is crucial for developing strategies to prevent future pandemics. The origins of SARS-CoV-2 have been a topic of extensive research and debate. While bats are considered the primary reservoir, the pathway through which the virus was transmitted to humans remains under investigation. Studies have suggested that intermediate hosts, possibly species sold in wildlife markets, may have facilitated the spillover. The discovery of HKU5-CoV-2 reinforces the need for stringent controls on wildlife trade and increased surveillance of animal populations that are in close contact with humans. In conclusion, the identification of HKU5-CoV-2 serves as a reminder of the dynamic nature of viruses and their ability to cross species barriers. While there is no immediate cause for alarm, this finding emphasizes the importance of proactive research and surveillance to identify and mitigate potential zoonotic threats before they can impact human health on a global scale.