Also known as "feline viral rhinotracheitis", feline herpes (FVR) is an acute upper respiratory disease of cats caused by the feline herpesvirus type 1 or FHV-1.

Feline herpesvirus is the most common cause of upper respiratory disease in cats, it is more common in kittens, cats in stressed/overcrowded environments such as animal shelters & multi cat households. Kittens & older cats are more at risk than healthy adults, and are also at greater risk of dying. Once your cat becomes infected with the feline herpesvirus it will have it for life.

The first outbreak is usually the most severe. Once recovered, in the healthy cat the immune system usually manages to keep the virus in check, but there may be the occasional outbreak at times of stress (pregnancy, lactation, overcrowding, while boarding etc.) or sickness. Corticosteroid injections may also bring on an outbreak in the infected cat.