I have wondered about the "upper respiratory virus" my cat had in late February. He was sneezing a lot and had a real raspy horse meow. No eye or nasal discharge. His appetite was good and he didn't seem to be in any distress. Hard to tell if a middle-aged cat is sleeping more than normal.
I took him to the vet's and $800 later they diagnosed an upper respiratory virus and said to let it run its' course, no meds required. Two more days and he seemed just fine. About the same time I had what I thought was a mild cold with a general run-down feeling. Now I am questioning what we both might have had.