Although it's not specified in common dictionary definitions...
"...zoonosis (a disease communicable from animals to man under natural conditions)." —Laurie Garrett, _The Coming Plague_ (Ch 14, section IV)
Which is naturally how the word is used virtually all the time.
Transmission from lab animals kept for study in a biolab, you could argue either way. Transmission from humanized lab animals purposely subjected to serial passage is not really zoonosis in any reasonable sense.