Lions worked with polio viruses, back in biology school. Don't have any memory of what experiment it was for, but it might have been using polio as a vector for altering the genes of another cell. 70 years ago, it would have been unthinkable to use polio viruses in a class, but it was assumed we were all vaccinated & the procedures were very aseptic.

Most of what humans know about viruses comes from handling viruses in labs. A lot of biology money goes to making viruses jump hosts, for use in gene editing. Some of them are extremely dangerous & there are serious protocols for keeping them contained.

Eating bats dates back to the Mao famine, yet China's large virus outbreaks only became consistent events 20 years ago, when gene therapy was big & lions were majoring in biology.

Maybe a butcher contracted it from a bat, but maybe a worker in a biology lab got it & gave it to the butcher. It would be easy enough to compare mutations in the virus to natural mutations, to determine if it was an experimental virus.