Educational Resources

Feline Upper Respiratory Infections

What are the common symptoms of an upper respiratory infection (URI)?

  • Frequent sneezing which usually begins with a clear, watery nasal discharge that may become thick and greenish or yellow in color
  • Runny eyes that may be red and swollen, squinting
  • Nasal congestion, producing “snorting” noises and causing some cats to hold their mouths open to breathe
  • Fever which results in lethargy and poor appetite
  • Signs of a sore throat, including gulping, swallowing frequently, drooling, and reluctance to eat

What causes most URIs?
Most URIs are the result of infection with a virus. Like humans, there are many viruses that can cause upper respiratory disease. The most common virus that causes URIs in cats is herpesvirus. Signs of infection range from mild to severe and may last a few days to several weeks. Recovered cats may become carriers, meaning that they can have recurrent infections or infect other cats. Calicivirus is another virus that can produce mild to severe URIs. This virus is also associated with the formation of oral ulcers and may be fatal, especially in kittens. All viruses cause irritation and damage to the nasal passages which predispose cats to secondary bacterial infections. Rarely, cases are primarily bacterial and are caused by Chlamydophila felis, Bordetella, or Mycoplasma species.

Which cats are at risk for URIs?
Kittens, geriatric cats, and cats with other diseases are most susceptible to upper respiratory infections. Although, it is important to note that any cat can acquire an infection, even if it is indoors only. Upper respiratory viruses are easily transmitted from cat to cat through aerosol transmissions, like sneezing. The virus may also be transmitted via contact with contaminated objects or handling after contact with an infected cat.

Breeds with shallow facial conformation (such as Persians), cats infected with feline leukemia or immunodeficiency virus, cats exposed to many other cats, and those with other diseases such as kidney failure, diabetes, and cancer are also predisposed to infection. Stressful environments or events may also suppress a cat’s immune system and make them more susceptible to infection. Cats that are boarded or are transitioning to a new household are also more susceptible to URIs because of stress.

How is a URI treated?
In many cases, only supportive care is needed to help a cat recover from a URI:

  • Feeding palatable foods, possibly warmed to increase aroma or syringe-feeding if the cat will not eat voluntarily, elevating food and water dishes to chin height
  • Fresh, clean water available, fluid therapy if dehydrated
  • Keeping your cat indoors in a warm, protected environment
  • Humidifying the environment (a steamy bathroom or humidifier)
  • Keeping the nostrils and eyes clear of thick secretions by gentle cleaning
  • Medications, if prescribed
    • Artificial tear drops, to reduce eye inflammation
    • If there is evidence of bacterial infection (lethargy, poor appetite, green or yellow discharge, or fever), antibiotics will be prescribed.
    • Immunostimulants or pediatric nasal drops may be prescribed as a supportive measure
    • L-Lysine, an amino acid, sometimes is used to treat viral infections as a supportive measure. It is thought that L-lysine prevents viruses from replicating normally, giving the immune system more time to respond to the infection.

How long will it take until my cat is well?
Symptoms of a URI can last from 4–21 days. Sneezing is the symptom that often lingers the longest, sometimes not disappearing until 3–4 weeks after infection. However, if symptoms are not improving after 10–14 days, make an appointment to have your cat re-evaluated. Your cat may have something more complicated than a routine URI.

My cat has continual bouts of runny eyes and/or sneezing—what causes this?
The most common cause of intermittent and chronic conjunctivitis (inflammation of the tissues surrounding the eyeball) and rhinitis (characterized by a runny nose and/or sneezing) is a persistent herpes virus infection. Some cats that acquire a herpes infection never eliminate it from the body. From time to time (up to several times a year and often after a stressful event) cats develop mild symptoms which generally do not require medical attention. We will often see a recurrence of infection after a cat has been boarded, while the owner is moving, or during other stressful situations.

Are URIs contagious to people?
Although it may seem that you and your cat sometimes get sick at the same time, the viruses that cause feline URIs are not transmissible to humans, and vice versa. The more likely explanation for this is that a pet and its owner may experience common stressors (such as changes in weather). However, in extremely rare cases, humans and cats may both be affected by Chlamydophila felis (a bacterium). The feline herpes virus is not related to human herpes infections.

How can I prevent URIs?
Although they are not 100% effective, vaccines are available for feline herpesvirus (the “VR” in the FVRCP vaccine) and calicivirus (the “C” in FVRCP). A series of booster vaccinations are administered to kittens and are repeated at various intervals throughout your cat’s life in order to maintain adequate levels of immunity.


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