These episodes may recur for the life of the cat though as the cat matures, symptoms become less and less severe and ultimately may not be noticeable to the owner. A cat with Herpes is contagious to other cats for a couple of weeks after a stressful event. Cats infected with Calici are contagious for several months after infection but do not appear to have recurrences the same way cats with Herpes do. Sometimes though an upper respiratory infection can be serious. If a cat is sick enough to stop eating or drinking, hospitalization may be needed to support him or her through the brunt of the infection.
Painful ulcers can form on the eyes, nose or in the mouth.
Sometimes fever is high enough to warrant monitoring. In young kittens, pneumonia may result from what started as an upper respiratory infetion. If you think your cat or kitten is significantly uncomfortable with a cold you should seek veterinary assistance with an office visit. The reason for this is that it is common for these viral infections to become complicated by secondary bacterial invaders. The antibiotics act on these.