seafood market

(Photo by Francesco Ungaro from Pexels)

TUCSON, Ariz. — The origins of COVID-19 have been a mystery since the virus emerged in 2019. Scientists have traced the virus — which has killed over six million globally — to the Chinese city of Wuhan. However, what’s still unclear is how COVID became a deadly pandemic. Did the virus naturally jump from animals to people, or did local researchers create it in a lab? Now, two new studies may have found an answer.

An international team says live animals sold at the Huanan Seafood Wholesale Market in Wuhan were the likely source of the pandemic and that the virus jumped from animals to humans on more than one occasion. The studies also claim that alternative COVID-19 origin theories are extremely unlikely.

In the first study, researchers from the University of Arizona and Scripps Research analyzed the geographic pattern of COVID-19 cases in the first month of the outbreak in December 2019. Researchers were able to determine the locations of nearly all of the 174 coronavirus cases identified by the World Health Organization at that time. Of those 174 cases, 155 were in Wuhan.

These cases were tightly congregated around the Huanan market, with later cases spreading widely throughout Wuhan — a city of about 11 million people. Researchers discovered that a large percentage of early COVID-19 patients had no history of recently visiting the Wuhan market but resided significantly closer to it than other people.

Lead author Michael Worobey, an evolution expert at the University of Arizona, says this shows that the market was the epicenter of the pandemic — with vendors getting sick first and then setting off a chain of infections among the community.

“In a city covering more than 3,000 square miles, the area with the highest probability of containing the home of someone who had one of the earliest COVID-19 cases in the world was an area of a few city blocks, with the Huanan market smack dab inside it,” says Worobey, who heads the university’s Department of Ecology and Evolutionary Biology, in a university release.

Worobey says another finding was able to support this conclusion. When researchers looked at the geographical distribution of later COVID cases, from January and February 2020, they found a “polar opposite” pattern. Those cases coincided with areas of the highest population density in Wuhan, while the cases from December 2019 mapped “like a bullseye” on the market.

“This tells us the virus was not circulating cryptically,” notes Worobey. “It really originated at that market and spread out from there.”

Which animals spread the virus?

In the first study, researchers also examined swab samples from market surfaces like floors and cages after the Huanan market closed. Samples testing positive for the SARS-CoV-2 virus tended to come from stalls selling live wildlife.

Researchers determined that animals now known to be susceptible to the virus, including red foxes, hog badgers, and raccoon dogs, were sold in the Huanan market in the weeks prior to the first recorded COVID-19 cases. Researchers ended up developing a detailed map of the market and showed that positive samples reported by Chinese scientists in early 2020 had a clear association with the western portion of the market. This area is where merchants butchered meat or sold live animals in late 2019.

“Upstream events are still obscure, but our analyses of available evidence clearly suggest that the pandemic arose from initial human infections from animals for sale at the Huanan Seafood Wholesale Market in late November 2019,” explains Kristian Andersen, co-senior author of both studies and a professor in the Department of Immunology and Microbiology at Scripps Research.

Animal transmission was likely rampant in Wuhan

For the second study, researchers combined epidemic modeling with analyses of the virus’ early evolution based on the earliest sampled genomes. Scientists determined the pandemic likely arose from at least two separate infections of humans due to animal contact at the Huanan market in November and possibly December 2019. Their analyses also suggested there were several other animal-to-human transmissions of the virus at the market, but these failed to develop into COVID-19 cases.

Researchers conclude that COVID-19 originated through jumps from animals to humans at the Huanan market. These animals likely contracted the virus from coronavirus-carrying bats in the wild or on local farms in China.

“To more fully understand the origin of SARS-CoV-2, we need to more fully understand events upstream of the Huanan market, which will require close international collaboration and cooperation,” Andersen concludes.

The findings are published in the journal Science.

About Matt Higgins

Matt Higgins worked in national and local news for 15 years. He started out as an overnight production assistant at Fox News Radio in 2007 and ended in 2021 as the Digital Managing Editor at CBS Philadelphia. Following his news career, he spent one year in the automotive industry as a Digital Platforms Content Specialist contractor with Subaru of America and is currently a freelance writer and editor for StudyFinds. Matt believes in facts, science and Philadelphia sports teams crushing his soul.

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  1. Stephen Pinn says:

    The article does a good job in identifying the way Covid spread it doesn’t identify the source of the virus

  2. Lisa says:

    These live animal markets in China need to be shut down permanently! If the bats infected the animals, what can be done to eliminate these disease carriers? How did the disease develop in their bodies? Is China going to be held accountable?

  3. Dale Scott says:

    Let’s say a lab worker was infected first. The lab worker happens to go to the popular nearby market to pick up dinner. A market vendor is infected. The single lab worker stays home a few days with mild “flu-like” symptoms. The results would be identical. This is also assuming the data out of China isn’t tainted. That is a big assumption. In addition, if the Chinese government was convinced the wet market was the source, as they originally claimed, why in the world would they open the market back up weeks later??? I used to have some respect for the journal, Science.

  4. A.O. says:

    Matt & Editors:

    First of all I am troubled by Web page title, “Study Finds.” Did that way of framing the conclusions and results of the work of researchers come from journalists? Studies don’t really find anything. It’s researchers who conduct studies that publish their conclusions and results from a given study. If your title were more accurate, as in near the truth, then it would be “Researchers Find,” and not as it is, which is not the whole truth. By the way, I studied science on the Colorado Plateau in Arizona in Northern AZ.

    Also, why do serious scientists make statements as you published them herein, “The studies also claim that alternative COVID-19 origin theories are extremely unlikely.” Theory does not come off the cuff, but rather, it comes at the end of lots of analysis and synthesis of information, and more importantly, it can be repeated by other researchers using the same methodology, etc. Good science starts with a hypothesis, or a well thought-out assumption, or good educated guess, or even with a few pieces of evidence, but it’s not conjecture, speculation or good educated guess work that creates a “theory.” Again, studies don’t make claims, as the researchers along with the help of peers reviewing their analysis, and results that leads researchers who conduct the studies to make the claims, accordingly. However, those claims would NOT be theories, but alternative COVID-19 origin hypotheses that are unlikely. Every thought, idea, guess, even educated guessing, or assumption is NOT a theory, even when a scientist makes such claims according to speculation or guessing or conjecturing. I suggest that journalists learn the meaning of hypothesis, and conjecture, and then you can teach the public to better understand science, and how it works. Unfortunately, many scholars learn about theory from journalists, and the public is lead to believe that theory is nothing more than educated guessing even when there has been rigorous testing and verification of a hypothesis.

    Here is an excerpt from the National Academies of Sciences:

    “An idea that has not yet been sufficiently tested is called a hypothesis. Different hypotheses are sometimes advanced to explain the same factual evidence. Rigor in the testing of hypotheses is the heart of science, if no verifiable tests can be formulated, the idea is called an ad hoc hypothesis—one that is not fruitful; such hypotheses fail to stimulate research and are unlikely to advance scientific knowledge.

    A fruitful hypothesis may develop into a theory after substantial observational or experimental support has accumulated. When a hypothesis has survived repeated opportunities for disproof and when competing hypotheses have been eliminated as a result of failure to produce the predicted consequences, that hypothesis may become the accepted theory explaining the original facts.

    Scientific theories are also predictive. They allow us to anticipate yet unknown phenomena and thus to focus research on more narrowly defined areas. If the results of testing agree with predictions from a theory, the theory is provisionally corroborated. If not, it is proved false and must be either abandoned or modified to account for the inconsistency.

    Scientific theories, therefore, are accepted only provisionally. It is always possible that a theory that has withstood previous testing may eventually be disproved. But as theories survive more tests, they are regarded with higher levels of confidence.

    In science, then, facts are determined by observation or measurement of natural or experimental phenomena. A hypothesis is a proposed explanation of those facts. A theory is a hypothesis that has gained wide acceptance because it has survived rigorous investigation of its predictions.
    Science accommodates, indeed welcomes, new discoveries: its theories change and its activities broaden as new facts come to light or new potentials are recognized. Examples of events changing scientific thought are legion. Truly scientific understanding cannot be attained or even pursued effectively when explanations not derived from or tested by the scientific method are accepted.”

    SOURCE: National Academy of Sciences and National Research Council(1984), pp. 8-11.
    National Academies of Sciences, Engineering, and Medicine. 1992. Responsible Science: Ensuring the Integrity of the Research Process: Volume I. Washington, DC: The National Academies Press.

    In closing, journalists lead by example, and you have the responsibility to lead the public to the most truthful understanding of science and how science works. Theory is not extemporaneous explanations of natural phenomena, or the randomness thereof. Science is not about alternative “truths,” but about getting to a real understanding of the reality in which we live, think, and reside.

  5. Luke says:

    The Wuhan virology research center is almost next door to the seafood market. The testing of samples from the market is not new news. They were found and tested many months ago and were found not to be an intermediate between viruses such as were found in bats, but to be identical to the virus shed by initial human cases. The number of samples testing positive for the virus were extremely small compared to the total number of samples taken making it more likely that the material was deposited by a human host rather than transferred from a number of animals to a large number of humans. All of this is discussed, with extensive references, in the book “Viral”.

  6. Joe S. Ragman says:

    This is all bs. China created this virus with money and at the behest of/from the US democrat party to destroy Trump, his presedency, and the republican party. However, it wasn’t supposed to go world wide, that was an accident. Look up Diamond Princess cruise lines, and how it was introduced to the US, and purposely spread from coast to coast, and not quarantined. How the democrats and media made the “prediction” of how this would determine/effect Trump’s reelection, depending on how he handled it when it first “affected” the US in late 2019.. Why did the democrats raise such a stink, and call Trump a racist and xenophobe for trying to ban flights/people coming to the US from China…? There’s much more to this if you have the ability to think for yourself and do some research and not be a democrat/media parrot and sheep.

  7. Jim says:

    Let’s think about this: How in the heck would they do this?

  8. Dan says:

    This smacks of more obfuscation by the WHO, probably under threat from the CCP, which seems to be threatening everybody these days. The WHO may simply be trying to keep peace rather than find the truth. We’ve already had studies of the wet market and no evidence was found in any animals there. Now we suddenly get this reversal, and based on a CCP study (who would have every reason to lie, simply to avoid being disappeared by their government as some of the early Chinese scientists were, or outright killed).

    As others have noted, the Wuhan lab is also smack in the area of the early infections, just yards from the market. So the supposed geographic evidence also could implicate the lab. Which, by the way, is the only known repository of SARS-like coronaviruses in the region. The closest relative of the virus is found 900 miles away. In bats. Which are not sold at the market, even though we were initially led to believe they were.

    Dr. Andersen, quoted in the article, has also had credibility issues due to his being involved in the series of emails that delayed accurate information getting in the hands of the public. Also, he privately thought the lab could be a source. He is not the person to quote or rely on here.

    Very disappointed in the reporting in this article, which is essentially spreading propaganda from the CCP. Well, at least most of the media is simply regurgitating what they are told, unquestioningly, so I guess SF is no worse. But I thought they were better and they are losing their own credibility by uncritically examining this report, which proves nothing but makes big claims.