• A new study indicates that the wildlife trade likely facilitated the spread of SARS-CoV-2 to humans, similar to the 2002 SARS outbreak.
• The study refutes the theory that the COVID-19 pandemic originated from a lab leak in Wuhan, China.
• Researchers emphasize the increasing risk of zoonotic spillover events due to human-animal interactions and the importance of monitoring bat populations.

A recent study published in Cell examined the origins of SARS-CoV-1 and SARS-CoV-2, the viruses responsible for the SARS and COVID-19 pandemics. The research, led by scientists at UC San Diego and other institutions, suggests that both viruses likely spread to humans through the wildlife trade. By analyzing the viruses' evolutionary history, the study concludes that the rapid movement of the viruses across China could not have been achieved through natural bat dispersal alone, pointing to the role of infected animals sold in markets.

• What: A genetic study tracing the origins of SARS-CoV-1 and SARS-CoV-2, concluding that wildlife trade likely facilitated their spread to humans.
• Who: Researchers from UC San Diego, University of Edinburgh, University of Arizona, and other institutions. Key individuals include Joel Wertheim, Jonathan Pekar, and Michael Worobey.
• When: The study was published on May 7, 2025, analyzing events leading up to the SARS outbreak in 2002 and the COVID-19 pandemic.
• Where: The study focuses on Western China, Northern Laos, and the Huanan Seafood Wholesale Market in Wuhan, China.

The study provides compelling evidence supporting the zoonotic origin of COVID-19 and underscores the risks associated with the wildlife trade. By comparing the evolutionary paths of SARS-CoV-1 and SARS-CoV-2, the researchers demonstrate a similar pattern of viral transmission from bats to intermediate hosts and eventually to humans via markets. This research challenges the lab leak theory and highlights the importance of monitoring bat populations and regulating wildlife trade to prevent future pandemics. The scientists are still trying to identify the intermediate host that bridged the gap between bats and humans.

When you sell wildlife in the heart of cities, you’re going to have a pandemic every so often.

The various iterations of the lab-leak theory all assume that there is something different and inexplicable about the emergence of COVID-19 compared with the emergence SARS. There is nothing unique about how far SARS-CoV-2 had to travel to emerge in Wuhan...Hence, there’s no need to invoke a 'lab leak' to explain the geography of SARS-CoV-2 emergence.

At the outset of the COVID-19 pandemic, there was a concern that the distance between Wuhan and the bat virus reservoir was too extreme for a zoonotic origin. This paper shows that it isn't unusual and is, in fact, extremely similar to the emergence of SARS-CoV-1 in 2002.

Echoing the SARS outbreak, the COVID-19 pandemic likely stemmed from zoonotic spillover events facilitated by the wildlife trade, with viral transmission patterns tracing back from bats to humans. This highlights the crucial need for enhanced surveillance of bat populations and stricter regulation of the wildlife trade to diminish the risk of future pandemics. While the specific intermediate host for SARS-CoV-2 remains under investigation, research suggests the virus may have "hitched a ride" via the wildlife trade, traveling long distances from its origin in Western China or Northern Laos to reach Central China. Studies indicate that the ancestor of SARS-CoV-2 emerged just years before the pandemic, a timeframe too short for natural dispersal by bats. This implies human-mediated wildlife trade, rather than natural bat migration, transported the virus. Although bats are considered the natural reservoir of SARS-CoV-2, palm civets and raccoon dogs, common in live-animal markets, are potential intermediate hosts. Unsanitary conditions and the mixing of various species in wildlife markets create ideal conditions for zoonotic spillover. Deforestation and illegal trading of wildlife also bring humans into closer contact with wildlife, increasing the risk of zoonotic transmission. Implementing regulatory harmonization and timely information sharing are key to preventing future outbreaks.