Upper Respiratory Infections in Cats

Upper Respiratory Infections in Cats

Animals affected

Cats and kittens


Upper respiratory infections, also known as URIs, are very common in cats. They are similar to colds in people, but they are caused by different types of germs.

URIs are especially common in kittens, and almost all cats will have experienced an upper respiratory infection by the time they reach adulthood. A very large proportion of kittens adopted from shelters suffer from URIs shortly after adoption.

The vast majority of upper respiratory infections resolve within two weeks, and cats diagnosed with URIs generally have excellent prognoses.

Although termed respiratory infections, the mildest of these infections manifest as eye problems. More severe cases may involve sneezing or discharge from the nose.

Dozens, or possibly hundreds, of different viruses and bacteria cause URIs in cats. The most common are a type of herpes virus and a Chlamydia bacteria. Despite the implications of their names, these diseases are not sexually transmitted.

Most types of URI are technically contagious. However, infection depends largely on a weakened immune system, so many (or perhaps most) healthy cats who are exposed to the causative agents of URIs will not get sick.


Symptoms typically include one or more of the following:

  • One or both eyes held shut or partially shut
  • Clear, yellow, or green discharge from one or both eyes
  • Swelling of the membranes around the eyes, causing the eyes to look puffy
  • Sneezing
  • Nasal discharge
  • Increased respiratory noise due to sinus congestion
  • Coughing

Risk Factors

  • Young kittens are at dramatically increased risk of URIs because their immune systems are not yet fully developed.
  • Stress, triggered by events such as moving, introducing a new cat to the house, or family emergencies, weakens cats’ immune systems and predisposes them to URIs.
  • Kittens and cats who have had respiratory infections in the past have an increased risk of recurrent infections.
  • Exposure to large numbers of other cats causes stress and increases the likelihood of disease transmission.
  • Vaccines are available for some agents that cause URIs. Unvaccinated cats are at higher risk.
  • Cats with feline immunodeficiency virus (FIV), feline leukemia virus, or other concurrent illnesses are more likely to suffer URIs.


Most URIs do not represent a major threat to health or well-being. The vast majority will resolve spontaneously or with minor medical intervention.

Severe infections can lead to decreased appetite and failure to thrive, especially in kittens.

Profound, untreated infections can lead to changes in the anatomy of the sinuses. This, in turn, can lead to chronic sinus infections as well as other problems.

In rare circumstances, untreated upper respiratory infections can progress to life-threatening pneumonia.


Diagnosis is made based on symptoms and history. It is best for a veterinarian to examine any cat with a suspected URI to confirm the diagnosis.  In some cases blood tests or analysis of samples using polymerase chain reaction (PCR) are performed.


Many upper respiratory infections do not require treatment and resolve spontaneously over time.  Severe infections may be treated with one or more of the following.

  • Eye ointments.
  • Oral antibiotics such as penicillins.
  • Nebulization, or placing the cat in an environment with increased humidity to help break up respiratory secretions.
  • L-lysine, an amino acid that may be administered orally to inhibit herpes virus.
  • Antiviral medications are used in severe cases of herpes.

In all cases, nursing care is important. This involves ensuring that adequate food and water are consumed, as well as ensuring that crusted discharge does not accumulate around the nose and eyes.



Most URIs resolve within 14 days. Any cat with a URI that persists longer than 14 days should undergo a follow-up veterinary evaluation.



URIs are exceptionally common in kittens, especially those originating from a shelter or rescue organization.

URIs can be frustrating to treat. In rare instances, cats and kittens suffer from prolonged (longer than 14 days) URIs or repeated URIs. Often, individuals will outgrow these problems as their immune systems mature.

Because of the stress that is inherent in overcrowding, URIs are occur with increased frequency in households with multiple cats.

Cats with healthy immune systems have lower rates of upper respiratory infections. Therefore, the best way to prevent URIs is to offer a healthy, stable environment that is free of overcrowding. A good diet and plenty of love also help prevent URIs.

Although human forms of herpes and Chlamydia exist, they are distinct from the feline diseases. Transmission of these diseases between species does not occur.

Copyright © Eric Barchas, DVM All rights reserved.
The contents of this page are provided for general informational purposes only. Under no circumstances should this page be substituted for professional consultation with a veterinarian.