One of my cats is sneezing a lot. More and more every day. He's having a sneezing fit right now, in fact. He has no discharge from his nose though. Should I be worried yet? Or is it just a cold? This post somewhat coinsides with my other post about my new HIV + cat. Should I be even more worried for my other cat who is HIV +? Or could this just be like a common cold that shouldn't harm either of them?