Feline Upper Respiratory Disease

Feline upper respiratory disease (abbreviated URD) is a general term used to describe the sneezing, runny eyes, runny nose cat cold symptoms.

What causes URD?

The underlying cause of these cat colds are usually viruses (a cat-specific herpesvirus and feline calicivirus being most common). Rarely, bacteria such as Chlamydia, Bordetella can cause these symptoms. In some cases, your cat’s viral infection is made worse by bacteria. Bacteria take advantage of a busy immune system to create a secondary infection.

What are the main symptoms of URD?

The universal symptom of URD is sneezing. Depending on how severe your cat’s infection is, it may be the only clinical symptom. Other symptoms include eye and nose discharge (clear in the case of viral infection and cloudy yellow or green if bacteria are also involved). If the infection becomes chronic, then symptoms can include a dry or ulcerated nose and chronic, brown eye or nose discharge. In severe infections, the lower respiratory tract can become involved leading to pneumonia. As colds are a systemic infection, your cat may be lethargic, dull, and show decrease appetite.

How would my cat get URD?

The viruses that cause upper respiratory infections are casual contact viruses that can survive in the environment for long periods of time, and thereby spread by direct or indirect contact. If we pet a stray cat, or visit a friend’s cat that is ill, we can put our own cats at risk! Any areas where lots of cats are together, and in high-stress situations, such as groomers, cat shows, pet stores, boarding facilities, and animal shelters are prime areas to pick-up a cold because the sneeze of one cat, several cages down, can infect your cat.

How do we diagnose URD?

In hospital, we diagnose URD based on clinical symptoms. The only way to determine the exact cause of a URD is to take a sample (usually nasal, throat or eye discharge) and run several laboratory tests such as culture, if bacteria are suspected, or other tests (such as PCR) to identify viruses.

How do we treat URD?

As said before, URDs are most often caused by viruses. Viruses are a challenge to treat because they will not respond to antibiotic therapy. When deciding on a treatment plan, our goal is to treat appropriately for the symptoms your cat is presenting and may include the following:

  • Monitoring at home: This includes checking activity levels and appetite. If changes are noted, it is important to contact the clinic as soon as possible as changes to the treatment plan may be required. Anorexia is very common and is the most serious common complication of URD. Nasal secretions should be softened with water and removed.
  • L-lysine supplement: This is an amino acid supplement that gives high doses of lysine to your cat. Lysine is an important therapy because it targets the viruses to slow down their replication. If we can slow down how fast the viruses multiply, then it gives your cat’s immune system a chance to overcome the infection. Because these viruses have a slow lifecycle, it is important to continue with the lysine therapy for at least 30 days. For some cats, long-term to lifelong therapy may be required. Veterinary approved L-lysine supplements are guaranteed to be of high quality and flavored to be tasty for your cat. It comes in gel and powder forms.
  • Anti-viral eye/nose drops: The medication in this eye/nose drop is targeted against viruses. Please follow the prescribed directions. Remember that this drop needs to be kept refrigerated.
  • Antibiotic eye/nose drops: The medication in this eye/nose drop is an antibiotic, designed to control the secondary bacterial infection present in your cat’s upper respiratory passages. Please follow the prescribed directions.
  • Systemic antibiotics: Due to concerns over more severe, systemic bacterial infection, we are sending your cat home on oral antibiotics. To reduce the risk of antibiotic resistance and the creation of superbugs in our environment, it is important to finish all the medication.
  • Systemic anti-virals: The recent research is showing promising results in fighting viruses with systemic anti-virus medications. They target the viruses directly so there is hope that the primary cause for the URD will be eliminated.

What follow-up is required?

With appropriate treatment, we should begin to see improvement of clinical symptoms within 24 to 48hrs. Sneezing is often the last symptom to resolve. Although treatment of clinical symptoms is possible, a cure is often difficult as these viruses can cause lifelong, asymptomatic, infection. Some cats that are chronically infected may show recurrent eye infection, cloudy nasal discharge, chronic sneezing, or nose ulcers. In these cases, a cure is almost impossible and management of clinical symptoms is important.

How do I prevent URD?

The best way to help prevent URD outbreaks is to have your cat vaccinated. As stated above, the viruses that cause these colds linger in our environment. Therefore all cats, including strictly indoor cats, should be vaccinated. It is important to remember, however, that just like our flu vaccine, no vaccine provides perfect protection, but vaccination will help to decrease the severity of an infection during an outbreak.


The prognosis is good if anorexia and dehydration do not occur or if they are treated aggressively. Cats that fail to respond to appropriate therapy within 4 to 6 days should be tested for the feline leukemia virus (FeLV) and the feline immunodeficiency virus (FIV).

If you have any questions regarding the information in this handout, please do not hesitate to contact the hospital.