Feline Upper Respiratory Infection (URI)
Feline upper respiratory infections (URIs) are similar to the common cold in humans as they include signs such as sinus congestion, sneezing, fever, and runny eyes, but may be caused by several different viruses and bacteria. The two most common causes of a feline URI are feline herpesvirus type 1 (FHV-1) and feline calicivirus (FCV). While it can be difficult to distinguish between the two viruses in an infected cat, FHV-1 causes cats to be quite ill and tends to cause inflammation and ulceration of the eyes and nose. FCV tends to affect the mouth and lungs and is more commonly associated with mouth sores.
When a cat becomes infected with FHV-1 or FCV, they are also susceptible to infection with other bacteria such as Staph and Strep. Aside from viral infections, feline URIs can have bacterial causes as well, the most common of which include Chlamydia, Mycoplasma, and Bordetella. Bordetella is an organism implicated in canine kennel cough.
Feline URIs spread through close contact with an infected cat. Environmental contamination by secretions from the nose, eyes, or mouth become important modes of transmission in crowded environments such as shelters and catteries, especially with FCV. Cats recovering from such an infection can also shed the virus for months afterwards. Feline URIs are incredibly common – they are the leading disease concern in shelters with incidence rates as high as 30%. Cats infected with FHV-1 in particular, like all herpes viruses, will carry the disease for life. The virus will lay dormant until triggered by stress, causing a flare up.
All cats are at risk for contracting an upper respiratory infection, particularly those living in a shelter environment. Young kittens and older cats are at risk for more severe cases of infection.
Common signs of a feline URI include:
- Red, swollen, or runny eyes
- Runny nose
- Nasal congestion
- Loss of appetite
- Corneal ulcers
- Mouth sores
- Skin or footpad ulcers
Signs may last anywhere from 5 to 14 days. Severe cases may last up to 6 weeks and include weight loss. Cats infected with FCV in particular may also develop joint inflammation leading to lameness, but fortunately the limping syndrome typically only lasts 1-2 days.
Kittens with severe URIs can develop serious eye conditions leading to decreased vision or blindness. FHV-1 has also been implicated in damage to the internal structure of the nose leading to a chronic runny nose from rhinitis.
Your veterinarian will take your cat’s medical history and perform a physical examination to check for any signs of an upper respiratory infection. Your veterinarian may also take a fluid sample by swabbing the eye, nose, or back of the throat to test for the exact strain causing an infection, although this is not typically done unless 1) the illness lasts over 10 days, 2) the upper respiratory infection progresses to pneumonia, or 3) the outbreak involves multiple cats in a shelter or cattery or multiple deaths occur in affected kittens.
Like the common cold in humans, feline URIs must simply run their course and treatment is focused on alleviating symptoms, supportive care, and rest. In general, the prognosis for cats with a URI is very good, with the exception of young kittens or older cats who may experience a more severe infection. Your veterinarian may prescribe the following depending on your cat’s clinical signs:
- Antibiotics (only in cases where bacterial infection is suspected)
- Antiviral medications especially in kittens with severe eye infections
- Nebulizer treatment or saline nose drops
- Eye ointments
- Fluids for dehydration
- Hospitalization for fluids, oxygen, and nutritional support
Proper home care is an important component to treating cats with an upper respiratory infection. Cat owners can gently clean discharge from the nose and eyes using a warm, moist hand towel. If you notice your cat is not eating, offer canned food warmed gently in the microwave – this will stimulate their appetite by making it easier to smell the food, which can be difficult for your cat to do with a stuffy nose.
Cats with a severe infection may require a hospital stay that includes an oxygen tent if they are having trouble breathing and fluid injections for dehydration.
Vaccination is the best available method for protecting against feline upper respiratory infections caused by either FHV-1 or FCV. Both viruses are a part of the FVRCP core vaccine, meaning it is a vaccine veterinarian recommend for every cat. FVRCP is a combination vaccine that protects against the herpesvirus, calicivirus, and panleukopenia.
Cats infected with FHV-1 will typically be carriers for life. As the herpesvirus is activated by stress, reducing stress will help to decrease flare ups. Common causes of stress can include moving, boarding, other illnesses, the introduction of a new pet in the home, etc. Make sure to provide your cat with a stress-free environment by separating food bowls and litter boxes, providing hiding places and places to climb, using synthetic pheromones, and having toys available to play with.
If you have any other cats or pets in the household, make sure to separate the infected cat and place them in a quiet, stress-free room to rest. Make sure to wash your hands after handling your cat, as well as any objects used by them such as a food bowl, litter box, or bedding. Cleaning and disinfection are critical to preventing spread of the microbes causing URIs. Household bleach at a 1:32 dilution is an effective disinfectant against URI organisms.