Cat Flu: Symptoms, Causes & Treatment

What is Cat Flu

Many cat owners have experienced a kitty with a stuffy/congested nose, accompanied by sneezing, fever, or even a decreased appetite. These flu-like signs are very common and usually indicate that your cat has something called feline upper respiratory infection (typically abbreviated “URI” by your veterinarian). Upper respiratory infections, also referred to as the cat flu, in cats can be caused by a variety of viruses and/or bacteria, and range from causing mild illness to a more severe sickness that requires treatment by your veterinarian. 

Symptoms of cat flu

There are several symptoms cats can exhibit when they have an upper respiratory infection. An infected cat may exhibit one, a few, or all of the following signs:

• Upper respiratory symptoms such as a stuffy/congested nose
• Sneezing
• Discharge from the nose- discharge could be clear, white, yellow, or green.
• Teary, watery discharge from the eyes, swollen eyes, or squinting
• Coughing
• Decreased appetite
• Decreased energy level
• Hiding/isolating- many cats will confine themselves away from their owners when they do not feel well
• Fever

What causes cat flu and how contagious is it? 

There are many viruses and bacteria that can cause flu-like signs in cats. The most common causes include the feline herpes virus and feline calicivirus. These viruses are highly contagious among other cats, and cats usually develop an infection after exposure to other cats that are infected or to surfaces/objects that an infected cat has used (bedding/toys, etc.)

Many cats, especially those that come from outdoors or a shelter, are exposed to these viruses at a young age as they are constantly around other cats. As a result, cat flu in kittens is very common.

The viruses and bacteria that cause cat flu symptoms are not contagious to humans. Likewise, human flu cannot be transmitted to your cat. Cats can become infected by bird flu (avian influenza) but this is extremely rare compared to other causes.

Cats with shorter noses (smushed faces), such as Persians, Himalayans, or exotic shorthairs, tend to have higher incidences of cat flu compared to other breeds.

How To Treat Cat Flu?

An examination by your veterinarian is always a good idea when your cat is experiencing cat flu symptoms. The treatment for cat flu can vary and is usually dependent on how sick your cat is and if there is a secondary bacterial infection present. Some infected cats can have mild symptoms, such as a runny nose, watery eyes, and occasional sneezing, whereas others can stop eating and develop a fever.

Depending on the severity of your cat’s illness, your vet may prescribe antibiotics or suggest supportive treatment as your cat may improve with at-home remedies and time. Your veterinarian will use the history you provide them, findings on a physical exam, as well as your cat’s other medical history to determine an appropriate treatment plan.

Treatments for feline upper respiratory infections that could be prescribed by your veterinarian include:

• Antiviral medications
• Antibiotics (if your cat also has a bacterial infection, which is not always the case)
• Eye drops or ointment

At-home treatments can also help your cat recover from cat flu. Always ask your veterinarian first if supportive treatment combined with at-home treatments is appropriate and safe for your pet.

The following are some steps that you can take at home that may help with cat flu, even for older cats:

• Create a warm, moist environment for your cat with a humidifier or a warm/steamy shower to help break up congestion in your their nose and alleviate any sore throat pain
• Gently clean the dried discharge away from your cat’s nose and eyes with a warm and clean cloth. Eye drops or an eye ointment can help if your cat develops eye ulcers.
• Offer your cat wet/canned food (if they enjoy it) instead of their normal food may encourage them to eat. Cats are very dependent on their sense of smell to have an appetite, so if they are congested, their appetite can be poor. Adding wet food to the cat’s food bowls, as opposed to dry kibble, tends to be more fragrant and appetizing. Warming the wet food can also help encourage appetite (but make sure it’s not too hot!)
• Offering a high quality lysine supplement- There is anecdotal evidence that providing a lysine supplement to cats with upper respiratory infections or upper respiratory symptoms caused by the feline herpesvirus will benefit from a daily lysine supplement. Please consult your veterinarian to ensure this is appropriate for your cat and what products they may recommend.
• Offering a daily probiotic or “immune boosting” supplement- There is ongoing research about the benefits of prebiotics, probiotics and other immune system boosting supplements in helping treat and prevent cat flu. Please consult your veterinarian prior to using these supplements for your cat.

How long does cat flu last? 

Upper respiratory infections and symptoms can last a couple of days to several weeks and the time it takes for your cat to feel better is dependent on several factors, including:

• The severity of your cat’s symptoms
• Treatments performed (at home and/or by your veterinarian)
• Other underlying medical conditions- if adult cats have other underlying illnesses, such as kidney disease, diabetes, or dental disease, it may take longer for symptoms to improve
• Your cat’s stress level

There is a small proportion of normally healthy cats that can experience mild symptoms of cat flu all the time and throughout their entire life. Most cats still live happy and otherwise healthy lives. If your cat experiences trouble breathing, seek immediate veterinary attention.

The role of stress in cat flu

Stress can play an important part in causing cat flu and also prolong the time it takes for them to heal from cat flu.The most common viral causes of cat flu can be “opportunistic,” meaning when your cat’s immune system is not as strong, the viruses will take the opportunity to make your cat sick. 

There are many reasons why young kittens and adult cats alike can be stressed. Some of the most common causes include:

• Moving households (including moving from a shelter to a new home)
• Living in crowded or unsanitary conditions
• New people and other animals in the home
• Underlying illness- if cats are in pain or are sick for another reason, their immune system can be depressed/compromised, which can lead to upper respiratory infections

Stress is not the only reason your cat may have an upper respiratory infection, but it is worth consulting your veterinarian about your cat’s lifestyle and any changes at home to see if this could be a contributing factor.

Can cat flu be prevented?

Almost every cat will have direct contact with the viruses that cause cat flu because they are so common and contagious. However, this does not mean that it will always cause illness.

A commonly used vaccine to help prevent infection with feline herpesvirus and feline calicivirus is available, although it is not always completely effective it can sometimes help to relieve symptoms. Ask your veterinarian if this is appropriate for your cat.

Minimizing stress and daily supplements such as lysine may also help at preventing symptoms of cat flu.