Sneezing and a runny nose in young cats is almost always a viral infection; however, viral infections are not alwaysï¿½harmless colds but can be serious infectious disease. The severity of the illness varies from cat to cat, but in order to avoid later damage to eyes and lungs, every cat with suspected viral infection should be treated immediately. The longer you wait to bring him/her to the vet, the more elaborate and expensive the treatment will be.