• The study provides evidence that the initial spread of COVID-19 was likely due to the wildlife trade, similar to the 2002 SARS outbreak.
• Researchers traced the origin of SARS-CoV-2 to horseshoe bats in western China or Northern Laos, with spread facilitated by wildlife trade to Wuhan.
• The findings dispute the lab leak theory, suggesting that the emergence of COVID-19 is not unique compared to the emergence of SARS.

A new study published in Cell suggests that the initial spread of COVID-19 was likely due to the wildlife trade, mirroring the SARS outbreak in 2002. Researchers at UC San Diego and other institutions analyzed the genomes of SARS-CoV-2 and related coronaviruses, tracing their origins to horseshoe bats in western China or Northern Laos. They found that the virus likely spread to Wuhan through the wildlife trade, similar to how SARS-CoV-1 spread to humans. This evidence contradicts the theory that COVID-19 originated from a lab leak in Wuhan.

• What: A study suggests COVID-19's initial spread was likely due to wildlife trade, similar to the SARS outbreak.
• Who: Researchers from UC San Diego, University of Edinburgh, and University of Arizona, including Joel Wertheim, Jonathan Pekar, and Michael Worobey.
• When: The study was published in May 2025. SARS-CoV-2 originated in horseshoe bats several years before the first COVID-19 cases were reported in Wuhan.
• Where: The precursor to SARS-CoV-2 originated in horseshoe bats in western China or Northern Laos, and spread to Wuhan, China.

The study provides compelling evidence linking the initial spread of COVID-19 to the wildlife trade, challenging the lab leak theory. By comparing the evolutionary history of SARS-CoV-2 with that of SARS-CoV-1, researchers found striking similarities in their spread patterns. Both viruses likely originated in bats and were transmitted to humans through intermediate animal hosts sold in wildlife markets. This suggests that the emergence of COVID-19 is not unique and can be explained by natural zoonotic spillover events. The findings underscore the risks associated with the wildlife trade and the importance of monitoring wild animal populations for potential viral threats.

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.

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

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.

The latest research strengthens the argument that the COVID-19 pandemic originated in the wildlife trade, akin to the SARS outbreak, with the SARS-CoV-2 virus likely traveling from bats in western China or northern Laos to Wuhan via intermediate animal hosts. This challenges the lab leak theory, emphasizing the significance of monitoring zoonotic spillover events. The specific intermediate species remains unknown, but evidence points to wild animals traded for meat or fur. This highlights the risks of human contact with wild animals and the crucial need for surveillance of bat populations and animals in live-animal markets to prevent future pandemics. Furthermore, the study underscores the rising risk of zoonotic pandemics due to habitat destruction, urbanization, and the global wildlife trade.