More than 47,000 live animals were on sale in Wuhan markets for over two years before the first Covid-19 cases were reported there in late 2019, new research showed, highlighting the risks of disease from China's wildlife trade.

A paper published in the journal Scientific Reports said as many as 38 species were sold in 17 markets in Wuhan between May 2017 and November 2019, including 31 protected species, with poor welfare and hygiene raising health risks.

Many of the earliest cases of human Covid-19 infection...