Drooling Cats. Is Cat Flu to Blame?

What is Cat Flu?

Cat flu is an upper respiratory infection in cats caused by viruses like feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), and Chlamydophila felis [1]. These viruses are highly contagious and can spread between cats through direct contact, shared items like food bowls, and airborne particles from sneezing and coughing.

Cat flu is similar to the common cold or influenza in humans. It often causes cold-like symptoms in cats like sneezing, runny nose and eyes, fever, lethargy, loss of appetite, and mouth ulcers. Though usually mild, cat flu symptoms can persist and lead to more serious issues like pneumonia if left untreated.

While called “flu,” cat flu itself is not the same virus that causes influenza in humans. But the viruses that cause cat flu produce similar upper respiratory infection symptoms in cats.

Symptoms of Cat Flu

The main symptoms of cat flu include:

Sneezing, coughing, fever – Cats with cat flu will often have nasal discharge and sneeze frequently. They may develop a fever as their body fights the infection. Coughing can occur as their airways become irritated. (https://www.bluecross.org.uk/advice/cat/health-and-injuries/cat-flu)

Runny eyes, nose, mouth – Infected cats commonly have a runny nose and discharge from their eyes. Their eyes may become inflamed. Drooling and foamy saliva can occur due to ulcers forming in the mouth. (https://www.trudellanimalhealth.com/learn/further-reading/cat-flu-signs-symptoms-treatments)

Ulcers in mouth – Ulcers and inflammation in the mouth are a common symptom. This can make eating painful. (https://www.bluecross.org.uk/advice/cat/health-and-injuries/cat-flu)

Loss of appetite – Due to the mouth pain and ulcers, infected cats often lose their appetite and stop eating. (https://www.trudellanimalhealth.com/learn/further-reading/cat-flu-signs-symptoms-treatments)

Can Cat Flu Cause Drooling?

Excessive drooling is a common symptom of cat flu, caused by painful mouth ulcers and inflammation in the mouth and throat. The feline calicivirus and herpesvirus that cause cat flu can lead to painful ulcers forming on the tongue, gums, and other oral tissues. As noted by the International Cat Care group, “Mouth ulcers, coughing, excessive drooling of saliva and eye ulcers may also be seen” in cats with flu (https://icatcare.org/advice/cat-flu-upper-respiratory-infection/). These painful ulcers make eating and swallowing difficult for the cat, leading to increased saliva production and drooling.

The mouth inflammation caused by cat flu irritates the salivary glands and makes cats salivate excessively. As the Cats Protection charity explains, cat flu symptoms include “fever, loss of appetite, discharge from the nose/eyes and sneezing. It can also cause drooling and severe mouth ulcers” (https://www.cats.org.uk/northherts/feature-pages/about-cat-flu). The combination of these oral ulcers and irritated salivary glands leads drooling to be a very common symptom of cat flu.

Why Does Cat Flu Cause Drooling?

Cat flu is caused by viruses that attack a cat’s upper respiratory tract, including the oral cavities. When viruses infect the mouth, it can create painful ulcers and inflammation in a cat’s gums, tongue, and other oral tissues.

These painful mouth ulcers make eating and drinking very uncomfortable for cats. To cope with the discomfort, infected cats tend to drool and salivate excessively. The excess saliva production helps soothe inflamed areas and provides some pain relief.

According to VCA Animal Hospitals, “These cats will usually salivate or drool excessively as the ulcers are very painful.” The excessive drooling is a visible sign that mouth ulcers have developed as a result of the cat flu viral infection.

Other Causes of Drooling

In addition to cat flu, there are several other potential causes for drooling in cats:

Dental disease such as gum disease, tooth abscesses, and oral injuries can lead to pain and inflammation in a cat’s mouth, causing increased saliva production and drooling. Cats may drool with dental issues due to the discomfort, or because they have difficulty swallowing the extra saliva.

Nausea is another common reason for drooling in cats. Motion sickness, eating something toxic or spoiled, and conditions like pancreatitis can all cause nausea and excessive drooling. The drooling is often accompanied by vomiting or retching.

Certain toxins like antifreeze or insecticides are extremely dangerous if ingested by cats. Drooling and vomiting are common symptoms if a cat is poisoned by one of these toxins. Immediate veterinary treatment is crucial.

In some cases, seizures or neurological issues like a facial nerve paralysis can also lead to drooling. Cat parents should monitor for other signs like twitching, loss of balance, or inability to blink or control facial muscles on one side.

Finally, stress and anxiety can also cause some cats to drool excessively. Environmental changes, new people or animals, and loud noises are just some of the potential stressors.

Diagnosing Cat Flu

To diagnose cat flu, a veterinarian will typically start with a thorough physical exam of the cat. They will check for symptoms like sneezing, coughing, runny nose and eyes, ulcers in the mouth, fever, and lethargy. The vet will also ask about the cat’s vaccination history and any potential exposure to other infected cats [1].

If cat flu is suspected, the vet may take samples from the cat’s nose and throat using swabs. These samples can be tested for the presence of calicivirus and herpesvirus [2]. However, testing is not always necessary if the symptoms clearly point to cat flu.

The vet will also rule out other potential causes of the symptoms, such as dental disease, allergies, respiratory infections, or injuries [3]. Diagnosing cat flu relies heavily on recognition of the typical clinical signs and ruling out other illnesses.

Treating Cat Flu

Cat flu is usually caused by viral infections, so antibiotics are not effective against the viruses themselves. However, antibiotics may be prescribed by a veterinarian to treat or prevent secondary bacterial infections that can occur with cat flu.

According to the Blue Cross, “Your vet may prescribe antibiotics if symptoms are severe, but they are not always needed.” [1] Antibiotics can help fight off bacterial infections that take hold when a cat’s immune system is compromised by the cat flu virus.

Anti-inflammatory medications may also be prescribed to reduce fever, swelling, and inflammation associated with cat flu. As WebMD notes, “Your vet may prescribe antibiotics to fight off the infection, or anti-inflammatories to help lower the fever.” [2]

In severe cases, antiviral medications may be used to treat the viral infection itself. However, according to Trudell Animal Health, “There are currently no effective antiviral drugs to treat viral upper respiratory infections.” [3] So antivirals are not routinely used for cat flu.

Recovery Time

The recovery time for cat flu can vary depending on the severity of the infection. According to Trudell Animal Health, “Cat flu recovery time is around 5 to 10 days for mild cases, and up to 6 weeks in more severe cases.” The Blue Cross also notes that “Many cats will recover and are no longer contagious after one or two years.”

In mild cases of cat flu, symptoms usually resolve within 1-2 weeks with proper treatment and care. Cats may continue to have some lingering nasal discharge or eye irritation during this time. Their appetite and energy levels also gradually return to normal.

More persistent or severe cases of cat flu can take over 4 weeks for a cat to fully recover from. They may require extended courses of antibiotics, antivirals, and supportive care like supplements and fluids. Even after symptoms resolve, the cat may continue to carry the virus and have occasional flare-ups when stressed or immunocompromised.

Preventing Cat Flu

There are several ways to help prevent your cat from getting cat flu:


The best way to protect your cat against cat flu is by getting them vaccinated. Kittens should receive an initial vaccination course of two injections, 2-4 weeks apart, followed by a booster a year later. Adult cats who have never been vaccinated will also need two initial injections. After that, annual vaccination boosters are recommended. The vaccination protects against the most common viruses that cause cat flu such as feline herpesvirus and feline calicivirus. While the vaccine doesn’t provide 100% protection, it can reduce the severity of symptoms if a cat does become infected. Consult your vet for their recommendation on the optimal vaccination schedule for your cat.

Limit exposure to infected cats

Since cat flu easily spreads between cats, limiting your cat’s exposure to unfamiliar or infected cats can reduce their risk. This means keeping them indoors and avoiding contact with neighborhood cats or cats at shelters and boarding facilities. New cats should be kept isolated from your existing cats for at least 10-14 days when first brought home.

Reduce stress

Stress is known to weaken the immune system, making cats more vulnerable to infections like cat flu. Providing a stable, low-stress home environment and limiting changes to their routine can help strengthen your cat’s immunity. Signs of stress include behaviors like hiding, aggression, excessive grooming, and urinary issues.

Good nutrition

Ensuring your cat eats a nutritionally balanced diet supports immune system health. Feed a complete and balanced commercial cat food appropriate for their age and activity level. Supplements containing vitamins, minerals, antioxidants and omega-3 fatty acids may provide added immune support.

When to See a Vet

If your cat is experiencing any of the following symptoms, it’s important to take them to the vet right away:

  • Drooling lasts more than 2 days (Source)
  • Not eating or lethargic behavior (Source)
  • Eye or nose discharge that won’t clear up (Source)

Cats with cat flu need veterinary attention if their symptoms persist or worsen. An untreated cat flu infection can lead to dangerous secondary infections or even pneumonia. It’s important not to wait and hope the symptoms will resolve on their own. Your vet can provide medications to help clear up the infection and relieve painful symptoms.

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