Lady vet here tells me that she has worked with corona for years. Chickens and cows, maybe?
corona viruses are mostly a mammal upper respiratory thing thing.
humans have several of them
so do dogs
cats have a few, one of which mutates into a fatal disease called FIP in vivo
SARS came from bats, as likely did COVID-19
MERS came from camels
part of why it's so difficult to test for is that the test has to be a very specific RNA (genetic) test for COVID-19 specifically. nearly every mammal (including humans) would test positive for generic "coronavirus" antibodies