What it is
The viruses spread through droplets from sneezing, saliva and eye discharge, and also through bowls, toys and hands. The disease moves easily wherever many cats live together, such as shelters or boarding catteries.
Cats choose their food by smell, so with a blocked nose food no longer appeals to them, and mouth ulcers make eating painful. A cat that does not eat weakens quickly, which makes appetite a key sign in this illness.
Herpesvirus does not leave after recovery: it hides in the body and can flare up again under stress. That is why some cats get repeated bouts of flu or eye inflammation. Ask your vet how to protect your cat from this disease.
Signs you may notice
A cat sneezes, has a runny nose and watery, sticky eyes, and may drool because of mouth ulcers. A blocked nose takes away its sense of smell, so it stops eating, turns listless and runs a fever.
When to see a vet
Book a visit if your cat has been sneezing with a runny nose for more than a few days, or if a kitten has cat flu. If it has not eaten for a day or more, contact a vet the same day, and if it struggles to breathe or breathes with its mouth open, immediately.
This is general information, not veterinary advice. For your own cat's health, tests and treatment, see a vet.