Upper Respiratory Infection in Cats

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What Is Upper Respiratory Infection in Cats?

An upper respiratory infection (URI) is an infection in the nose, sinuses, mouth, and/or throat. There are several infectious agents, both viruses and bacteria, that play a role in respiratory infections in cats.

During a URI, cats have inflammation and drainage in the mucous membranes of their nose and throat. They often have drainage from their eyes and nose and may experience significant sneezing. This occurs because the body’s defenses are trying to flush the infectious organisms from the body to eliminate infection.

Most URIs are contagious from cat to cat. The excessive secretions and sneezing help to spread the bacteria or viruses from one cat to another.

The most common “bugs” resulting in upper respiratory infections in cats are feline herpes virus (also known as feline rhinotracheitis) and feline calicivirus. There are many other organisms that may play a role in causing respiratory infections, including feline bordetella, chlamydophila, mycoplasma, and cryptococcus. 

Most upper respiratory infections are not considered a medical emergency. Severe URIs however, can lead to depression and a refusal to eat, which can be fatal in young kittens or senior cats who grow weak quickly without regular nutrition and adequate hydration.

Symptoms of Upper Respiratory Infection in Cats

• Sneezing

• Drainage from the eyes

• Conjunctivitis (swelling or redness of the membranes around the eyes)

• Squinting

• Nasal drainage or crust

• Nasal congestion

• Decreased or absent appetite

• Cough

• Lethargy

• Fever

• Ulcers in the mouth

• Lymph node swelling

• Difficulty breathing

Cat with severe upper respiratory infection and has a significant amount of nasal discharge and some ocular discharge.

Photo By: Sandra Mitchell, DVM

Causes of Upper Respiratory Infection in Cats

Most of the infectious agents that cause URIs are contagious and can be spread in several ways. Feline herpes virus notoriously leads to sneezing, which in turn leads to aerosol transmission. This occurs when one cat sneezes near another cat, who inhales the germs. Direct transmission can also occur from mutual grooming and cats rubbing against one another.

Many respiratory diseases are spread by fomites. A fomite is an object that was contaminated by one cat’s germs and then touched by another cat. Environmental exposure can come from food and water dishes, cages, bedding, and even humans—all of which can serve as fomites to spread URIs from cat to cat.

However, most of the viruses commonly implicated in feline URIs do not survive on surfaces for very long. For this reason, most infections are the result of direct exposure to an infected cat.

Immune status can also play a role in cats developing upper respiratory infections. When the immune system is weakened (by stress or concurrent disease), a cat is susceptible to contracting a URI. Therefore, it’s common for a shelter cat to show clinical signs of a URI 7-10 days after moving to a new home. Stress from the change in routine leads to decreased immune function and allows the virus or bacteria to grow stronger.

Additionally, some cats can serve as carriers of upper respiratory disease. They show no visible clinical signs but are still shedding viral particles and are infectious to other cats.

Risk Factors for Upper Respiratory Infection in Cats

There are several risk factors that increase a cat’s chances of contracting an upper respiratory infection. Kittens and senior cats with less robust immune systems, are more prone to catching URIs. Similarly, cats with underlying diseases taxing their immune system are also more susceptible. Cats that have a diagnosis of feline leukemia or feline immunodeficiency virus (FIV) are significantly more prone to URIs.

Certain breeds of cat with shortened noses or “smushed” faces are at a higher risk of complications. Those breeds, called brachycephalics, have shortened bones in the skull, giving the face a flat, pushed-in appearance. Brachycephalic cats include breeds like Persians, Himalayans, and Burmese. All may have more difficulty clearing an upper respiratory infection than non-brachycephalic breeds.

Stress plays a huge role in many of the diseases that commonly affect cats. For cats in animal shelters, URI is the most reported illness. Studies have shown that reducing stress (providing more places to hide, lowering noise volume, and increasing enclosure space) can reduce the incidence of respiratory disease.

Stress has a negative effect on the immune system, lowering its ability to fight infections. Feline herpes virus is unique because it can go into a dormant state where the virus is still present, but the cat is not actively shedding the virus at that time. When stress decreases immune function, the feline herpes virus comes out of remission, and the cat starts shedding viral particles, becoming clinical for the disease. The herpes virus is very common in cats. Studies estimate that up to half of healthy cats have been exposed and have the feline herpes virus dormant in their bodies.

Vaccinations can be helpful in reducing your cat’s risk of contracting an upper respiratory infection. Most cats who receive regular veterinary care get the FVRCP vaccine. If cats are up to date on vaccinations, they are much less likely to contract a URI. Additionally, if they do become infected, they are more likely to experience mild clinical signs that do not require treatment.

If your cat goes outdoors, or has increased exposure to other cats, your veterinarian may also recommend your cat be vaccinated for feline leukemia, which is spread from cat to cat through mutual grooming and shared food bowls or items.

Leukemia makes cats more susceptible to URIs as it tends to weaken the immune system. Spending time outdoors naturally increases a cat’s risk for exposure to upper respiratory infections, as cats are less likely to encounter infected cats when they are only inside their own home. Similarly, if your cat is picked up and put in an animal shelter, the likelihood of exposure increases. Boarding facilities may also be a source of exposure to feline URIs.

How Veterinarians Diagnose Upper Respiratory Infection in Cats

Upper respiratory infections are most often diagnosed based on a physical exam by a veterinarian.

Your veterinarian may recommend radiographs (x-rays) to look at your cat’s lungs and rule out any lower respiratory involvement, like pneumonia. Sometimes blood work is recommended, and/or feline leukemia and FIV testing to rule out underlying concurrent infections.

If the upper respiratory infection is severe or complicated and not responding to classic treatment, your veterinarian may recommend a culture and sensitivity or PCR test to identify the organism and determine the best course of treatment. In this procedure, the vet uses a swab to collect drainage from your cat’s nasal passages and sends it to a laboratory to either swab out the drainage on a petri dish and incubate to see what bacteria grows—or run PCR testing to identify any viral pathogens present.

Sometimes special imaging, like nasal endoscopy or CT, is recommended if a nasal polyp or mass is suspected as a cause of recurring secondary URIs.

Treatment of Upper Respiratory Infection in Cats

Upper respiratory infections are often treated with supportive care if a virus, like feline herpes virus or calicivirus, is suspected. Your veterinarian may recommend probiotics (like Fortiflora and Proviable) or amino acids supplements (like L-Lysine products, such as Viralys and Vetri Lysine Plus) to support your cat’s immune system as it fights the virus.

Some cats can benefit from steam therapy, and your veterinarian may recommend that you keep your cat in the bathroom while showering to keep nasal passages moist.

URIs in cats at times can involve bacteria, and these patients are usually prescribed an antibiotic. If your cat is prescribed an antibiotic, be sure to follow the label instructions exactly. Do not discontinue the medication before the course is complete and avoid missing doses. If the antibiotic prescribed to your cat is causing any gastrointestinal side effects, (like vomiting or diarrhea) let your veterinarian know to determine if an alternate medication would be better tolerated.

Severe URIs may require hospitalization with oxygen therapy and/or nebulization treatments and injectable antibiotics.

Are there home remedies to treat upper respiratory infections in cats?

Upper respiratory infections that are the result of a viral infection are often managed at home with supportive care. However, when bacterial agents are involved, these infections rarely resolve without antibiotic therapy. Talk to your veterinarian about your cat’s clinical signs to determine if prescription medications are required. The signs of a more serious infection, to be addressed immediately include:

• Decreased of absent appetite

• Fever

• Lethargy

• Green-yellow drainage from the eyes or nose

• Difficulty breathing

If your cat has any of the above clinical signs, reach out to a veterinarian right away to seek treatment. But if your cat is eating normally and has decent energy, you can continue to monitor the situation at home.

Recovery and Management of Upper Respiratory Infection in Cats

The average timeline of recovery for herpes viral outbreaks is typically two weeks. During that time, it is recommended that you monitor your cat closely. Make sure the cat is eating regularly and energy levels are improving, not getting worse. Probiotics may enhance the palatability of food and support gut health, while your cat’s body fights the virus. Water additives, like Purina Hydra Care, may increase water intake to keep your cat hydrated while the immune system is compromised.

Consider keeping your cat in the bathroom so it can benefit from the steam as you shower. Wipe any ocular or nasal drainage with a gentle wipe that is approved for use in cats, like those from Optixcare.

Remember, feline herpes virus is not cured, but rather managed. Cats diagnosed with feline herpes are susceptible to having another viral outbreak in the future. Stress is one of the biggest contributors to viral shedding. Consider managing stress as much as possible. There are many oral supplements on the market designed to help your cat manage stress, including Zylkene, Vetriscience Composure, and Purina Calming Care.

Some pet parents find that pheromone diffusers, like Feliway, are beneficial for managing stress. Environmental enrichment may also provide some stress relief for your cat. Make sure that your cat has easy access to all resources (food, water, litter box, and perch).

Prevention of Upper Respiratory Infection in Cats

Prevention of URIs is mostly done by vaccination and limiting exposure. Consider having a pet sitter, family member, or friend come to your house to care for your cat when you leave town, rather than using a boarding facility. Remember that going outside provides your cat with more opportunity to mingle with neighborhood cats or strays, increasing the risk of contracting a URI.

Vaccinations are very helpful at both preventing infection and reducing the severity of clinical signs in cats with URIs. Follow your veterinarian’s recommended vaccine schedule and keep your cat up to date on all recommended inoculations.

If your cat already has an underlying feline herpes virus infection, minimize stress as much as possible to reduce shedding of the virus.