In mid-November 2019, a batch of seafood from Maine, USA was shipped to Wuhan South China Seafood Market through the cold chain. In just a few weeks, employees of many merchants in the South China Seafood Market experienced symptoms of pneumonia of unknown origin one after another, and they were infected with new coronary pneumonia.

In mid-November 2019, a batch of seafood from Maine, USA was shipped to Wuhan South China Seafood Market through the cold chain. In just a few weeks, employees of many merchants in the South China Seafood Market experienced symptoms of pneumonia of unknown origin one after another, and they were infected with new coronary pneumonia.