[jacquesm]

All it would take is a bat taking a dump on a pigsty and then the unlucky pig that now happens to be infected being taken to the market. Which is the most likely backstory of several other bat-to-intermediary-to-human viral jumps. And if you're unlucky the intermediary species doesn't just carry the virus but serves as an amplifier. Hendra for instance.

[nradov]

Fecal-oral transmission of SARS-CoV-2 is suspected to be possible, but I don't think it has ever been definitively established.