PRINCETON, NJ – Great uncertainty surrounds the origins of SARS-CoV-2. Early on, some suggested a link between COVID-19 and a fish market in Wuhan, China. Other theories are now circulating, although the origins of the virus are still unknown.

In response, governments have pushed for the closure of so-called “wet markets” around the world, but this is not an effective policy solution, researchers at Princeton University report.

Widespread closure of all wet markets could have the unintended consequences of disrupting critical food supply chains, stimulating an unregulated black market in animal products, and fueling xenophobia and anti-Asian sentiments. In addition, the majority of these informal markets – which specialize in fresh meat, seafood and other perishable outdoor products – pose little risk to human health or biodiversity.

Instead, policymakers should target the riskiest aspects of markets to prevent disruption to local food supply chains while reducing threats to human health and biodiversity, the researchers argue in the journal The Lancet Planetary Healthet. The markets that sell live animals, especially live wildlife, pose the greatest risks to human health and biodiversity, the researchers conclude.

“The use of the term ‘wet market’ is riddled with negative undertones, especially in light of COVID-19. I believe this is due in part to a misunderstanding of what these markets actually are and how they can differ from and from other markets. Given this confusion, the term is slowly being replaced in the academic and popular literature with more specific terminology, ”said Bing Lin, lead author of the study, a sophomore student. Student in the Science, Technology and Environmental Policy program at Princeton School of Public and International Affairs. “Our research clarifies what wet markets are and how their risks can be considered and classified.”

“In the wake of the COVID-19 pandemic, many nations have temporarily closed their wet markets, but that will not last – at some point some will be opened while others will be more strictly regulated or closed entirely,” said co-author of the study David S . Wilcove, Professor of Ecology and Evolutionary Biology and Public Affairs at the High Meadows Environmental Institute and a member of the core faculty at the Princeton Center for Policy Research on Energy and the Environment. “Our work provides a way to see which ones are worth focusing on for tighter regulation or closure.”

Lin and Wilcove began by defining wet markets, which sell consumer-oriented, perishable goods in an environment outside of the supermarket. These markets are named for their often wet floors, created by washing regularly to keep food stalls clean and melting ice to keep food fresh. Wildlife markets, on the other hand, sell non-domesticated wildlife and live animal markets sell live animals. Huanan Seafood Wholesale Market – which is believed to be a potential source of the COVID-19 pandemic – was a wet market, live animal market, and wildlife market rolled into one.

To help policymakers distinguish relatively harmless markets from dangerous ones, Bing and its staff analyzed the different types of markets, how they work and what risk they pose to humans and animals. They then developed a unique framework that identifies the main risks associated with these markets, including size and cleanliness, whether they sell high-risk animals, and the presence of live animals.

For the paper, Lin and Wilcove drew on medical and peer-reviewed literature on markets from July to December 2020. They assessed six specific risks that informal markets can pose to human health: the sale of animals at high risk of disease; the presence of live animals; Hygiene conditions; Market size; Animal density and interspecies mixing; and the length and extent of the animal supply chains. They also identified the factors that pose risks to biodiversity, including sales of threatened and declining wildlife.

They report that numerous moist markets around the world only sell processed domesticated animals such as poultry. This includes all markets in Singapore and Taiwan as well as the farmers markets in the USA. A smaller number of markets sell live domesticated animals. Still fewer are selling wild animals, dead or alive, alongside livestock or meat from domesticated animals.

When you compare all of these, the markets that sell live animals pose the greatest risks to human health and biodiversity, especially when they sell live wildlife – which are linked to emerging infectious diseases. These are the markets that policy makers should target when trying to contain future infectious disease outbreaks, the researchers report.

“When I grew up in Greater Indonesia and in the midst of the hustle and bustle of downtown Taiwan, I knew from experience that wet markets differ dramatically in terms of their composition and texture,” said Lin, “and good politics must be based on a clear but differentiated understanding are based. ”of the different types of markets and the associated and variable risks. We believe that targeted, risk-adjusted measures to mitigate the highest market risks are preferable to comprehensive, but ineffective, short-term change. “

The researchers emphasize that these markets are not solely responsible for global pandemics. Instead, they represent a hub of zoonotic transmission potential along the global wildlife trade supply chain. They hope that future research will continue to quantify the risk factors in these markets so that decision-makers can better protect human health and biodiversity.


The paper “Better Classification of Wet Markets is Key to Protecting Human Health and Biodiversity” was published on June 10 in. released The Lancet Planetary Healthet. Other co-authors are Madeleine L. Dietrich ’20 and Rebecca A. Senior, a postdoctoral fellow at Princeton SPIA.

The researchers cite the High Meadows Foundation for supporting the work of Lin, Senior, and Wilcove; and the World Wide Fund for Nature for supporting part of Dietrich’s research.


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