Glossary

Upper respiratory infection

A contagious infection of the nose, throat and eyes that causes sneezing, discharge and a poor appetite, common in kittens and shelter cats.

Also called: URI, cat flu, feline respiratory disease complex, snuffles

An upper respiratory infection, or URI, is the cat equivalent of a bad cold, often called cat flu. Most cases come from feline herpesvirus or feline calicivirus. Bacteria such as Chlamydia felis, Bordetella bronchiseptica and Mycoplasma can cause or add to the illness. It spreads easily in shelters, catteries and homes with several cats.

Typical signs are sneezing, runny or crusty eyes, a congested nose, drooling, a mild fever and tiredness. A cat that cannot smell its food may stop eating, which can become dangerous quickly, especially in kittens and in overweight cats. Mild cases often ease within a week or two, though some cats keep flaring up.

See a vet the same day if your cat refuses food for more than a day, breathes with an open mouth, has green or bloody discharge, a squinting eye, or is a young kitten or an older or sick cat. A vet may examine the cat, take swabs and offer supportive care, and may prescribe medicines where bacteria are involved. Keep a sick cat apart from others and ask your vet which signs to watch. The FVRCP vaccine reduces how severe these infections are.

Last reviewed November 7, 2026

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Related terms

Feline herpesvirus A common virus that causes sneezing, eye inflammation and nasal discharge, and stays in the body for life, flaring up in times of stress. Feline calicivirus A common virus behind cat flu that causes sneezing, eye discharge and painful mouth ulcers, and sometimes severe illness. FVRCP vaccine The combination cat vaccine that protects against feline herpesvirus, calicivirus and panleukopenia. Feline asthma A long-term inflammation of a cat's small airways that causes coughing, wheezing and sometimes sudden breathing difficulty. Dehydration A shortage of body water that can accompany vomiting, diarrhea, kidney disease and many other illnesses in cats.

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