Hi Deb, thanks for the reply.
He does eat human food a little, but not a lot. And my husband and I are both vegetarians so I know it couldn't have been spoiled meat or something like that. I opened 5 cans in the same case and all looked a little different.
I did call Wellness and they said take it back to where I bought it, full refund, etc. Which I did.
I don't want to Just give him dry food - but I bet dry has less chance of spoiling compared to wet.
Too bad the vet couldn't say where he might have gotten the bug. I doubt it was from our food because I'm Extremely sensitive and I know I would have gotten sick first.
Also, he's an indoor cat with no other pets around.