All our vets have said over the years that simple viruses/colds can pass from cats to humans and vice versa.

In fact Weez had a depressed white count when she went for her spay, so they cancelled her surgery for two weeks. Said viruses come in on your shoes and hands (even tho we wash our hands when we come back from stores and other people's homes.

Oreo had a terrible upper respiratory virus right after going to Vet #1...at the end of July... this was the visit that found her thyroid nodule. They did blood work--normal. But when we arrived on vacation she sneezed and coughed for two days! endlessly and drooled etc. I think she caught this at the Vet.
(our other cat--still a kitten did not catch it because they are not close and Oreo was upstairs, and Weez downstairs for that time period.

Vet #2 I took her to after vacation, found the tumor in her belly and now I got the biopsy results this morning from Vet #3= mast cell carcinoma. Very disturbing news....the lump was totally missed by Vet #1.

Now we decide if she is to get surgery or not...and just get put to sleep in the near future. A very sad and difficult thing deciding for a 13 yr old cat!