A detailed look at the coronavirus's first days at a Wuhan market

Michael Le Page is a person.

According to three preliminary studies, the covid-19 epidemic began when the SARS-CoV-2 virus jumped from animals to humans at the Huanan seafood market in Wuhan, China.

The picture is depicted by the studies. At some point before 2020, the ancestor of the coronaviruses jumped from bats into other mammals. We don't know what happened or which mammals were involved.

The coronaviruses was spreading among mammals kept in cages at the Huanan seafood market. There were nearly 600 objects at the market in January 2020. According to a report by the Chinese Center for Disease Prevention and Control, 33 people tested positive for the virus.

The precise locations of the positive objects have been mapped by an international group of coronaviruses researchers. The western part of the market where live mammals were kept was where 31 of the 33 objects were found.

There were five positive samples in one stall. A metal cage in the back room, two carts used to move cages, and a hair/feather removal product were all items that tested positive for animals.

There were live mammals present at the Huanan market in November of 2019. All of these animals can be carriers of the disease, and we know that the animals are capable of spreading it.

The coronaviruses jumped from one of the mammals to a person. It happened again around 2 December with a slightly different version of the virus.

Multiple sources show that the Huanan market was the source of the virus. The early covid-19 cases were clustered around the market, and many were directly linked to it. The first confirmed case of covid-19 was in a seafood vendor who went to the hospital on December 16th after becoming ill on December 10th.

If you only map those cases in December, they still cluster around the market.

Two distinct jumps

It has been known for a long time that there were two different versions of the same disease, known as lineage A and B.

There have been reports of intermediate forms, suggesting that one line came from another. A study by Jonathan Pekar at the University of California, San Diego and his colleagues suggests that the intermediate forms are a result of errors in the sequence of the virus, and that the two early lineages were the result of two separate jumps of the virus from animals.

George Gao at the Chinese Center for Disease Control and Prevention has done a third study that gives more information on the tests done at the market. This research shows for the first time that an object tested positive for A.

This is the first evidence that there are two versions of the same virus in the market. The market was the place where the jumps to people took place.

There is a chance that some mammals at the market were exposed to the SARS-CoV-2 virus, but that is not likely to happen anymore.

Stray cats, dogs, snakes, rabbits, and mice were tested by health authorities in China. The farms and wild areas that supplied the market were never tested, as far as the team is aware.

There are multiple lines of evidence that add up to a strong case.