If you’ve ever noticed your cat sneezing, drooling, or acting lethargic, you might have wondered if it’s more than a cold. One possible cause could be feline calicivirus. This virus is highly contagious, easily causing damage to a cat’s respiratory system and painful ulcers in the mouth.

Feline calicivirus is a significant cause of upper respiratory infections in cats and can sometimes cause more severe health issues, depending on the strain. It’s widespread among cats worldwide and spreads easily in environments where cats interact closely, such as shelters, catteries, and even multi-cat households.

This virus is particularly concerning because it can mutate, meaning some strains can cause severe symptoms, such as fever, joint pain, and even life-threatening conditions like pneumonia or systemic disease. In short, FCV can impact a cat’s quality of life in many ways.

How is Calicivirus Transmitted in Cats?

Feline calicivirus is one of the most contagious viruses, spreading rapidly through many ways. Here are ways calicivirus is transmitted in cats:

Direct Cat-to-Cat Contact

The most common way feline calicivirus spreads is through direct interactions between cats. Grooming, nuzzling, playing, or even fighting can transfer the virus from an infected cat to another healthy cat. Cats that appear healthy but are carriers of feline calicivirus can unknowingly spread the virus.

Direct contact is common in grooming salons, multi-cat households, and daycares. Additionally, cats can get infected through airborne particles. When an infected cat sneezes, tiny droplets of saliva or mucus containing the virus can travel short distances. These aerosolized particles may land on surfaces, objects, or other cats, spreading the infection. This is especially problematic in areas where the spaces are too tight and small.

Contaminated Surfaces or Objects

FCV is notorious for its ability to survive in the environment for extended periods. This makes objects like food and water bowls, litter boxes, toys, and bedding potential sources of a calicivirus infection. Cats can contract the virus by touching or licking these contaminated surfaces.

Human Transmission

While humans cannot contract FCV, they can inadvertently spread it. Handling an infected cat and then touching another cat without proper handwashing can transfer the virus.

What are the Common Symptoms of Feline Calicivirus?

Feline calicivirus can present with a wide variety of symptoms, from mild respiratory issues to extreme complications. The symptoms depend on the certain strain of the virus, the cat’s immune system, and whether there are secondary infections. 

Respiratory Symptoms

One of the earliest and most common symptoms of feline calicivirus is sneezing. Frequent sneezing indicates irritation and inflammation in the nasal passages. Additionally, nasal discharge is to be expected when it comes to a calicivirus infection in cats.

The discharge may start clear but can turn thick, yellow, or green as secondary bacterial infections develop. Cats may show difficulty breathing due to clogged nasal passages. Additionally, nasal congestion can be a possible symptom. Swelling and mucus buildup can make breathing noisy or labored. Cats may breathe through their mouths if their noses are completely blocked.

Oral Ulcers

Ulcers in the mouth are a hallmark sign of feline calicivirus. These appear on the tongue, gums, or roof of the mouth and can cause discomfort, especially when eating. Cats may try to eat but stop after a few bites. Pain from oral ulcers, congestion, or general malaise often causes cats to stop eating or drinking. 

Additionally, cats may drool excessively because of oral discomfort or an inability to swallow properly. Drooling is common due to oral pain or ulcers, and a foul smell from the mouth may indicate severe infection or advanced disease.

Eye Discharge and Conjunctivitis

Calicivirus in cats often causes watery or sticky discharge from the eyes, which may crust around the eyelids. Conjunctivitis is also a possible symptom. Redness, swelling, and irritation of the tissues surrounding the eyes can make cats squint or rub their faces against objects for relief.

Fever and Lethargy

Most infected cats develop a fever, often making them listless or uninterested in their surroundings. Their temperatures might increase significantly. Additionally, cats can become lethargic. Cats may sleep more than usual, hide in quiet places, or avoid interaction.

Lameness

Some strains of feline calicivirus can cause inflammation in the joints, resulting in limping or difficulty moving. This symptom is more commonly seen in young cats and typically resolves on its own within a few days.

Other Conditions

In some cases, there will be severe symptoms to deal with. Pneumonia, liver damage, and bleeding in the GI tract are rarer symptoms that can also be possible.

How is Calicivirus Diagnosed in Cats?

Just like for any disease, diagnosing calicivirus in cats will involve a series of tests and exams. Here are the common tests we do:

Virus Isolation

Virus isolation is the most effective way to confirm calicivirus in cats, although it is less commonly used in clinical settings because it is incredibly expensive. A sample is taken from the cat’s nasal passages, throat, or eyes and placed in a culture medium. The virus is then grown in a controlled environment.

This process provides definitive proof of the virus’s presence and can give insights into the strain and virulence. However, it takes longer to yield results and requires a specialized laboratory to do so.

Polymerase Chain Reaction Testing

PCR testing is the most sensitive and widely used method for detecting feline calicivirus. It works by identifying the virus’s genetic material in a sample collected from the cat’s nasal passages, throat, or oral cavity. The sample is sent to our in-house laboratory for testing. 

PCR testing is extremely accurate, can detect the virus in asymptomatic carriers, and is useful for identifying different strains. However, it’s worth noting that a positive result does not always indicate active disease since healthy carriers of feline calicivirus can also test positive.

Other Tests

Other tests we use include blood tests and imaging techniques. Although blood tests can’t directly diagnose calicivirus in cats, they can help assess your cat’s overall health. Additionally, imaging tests such as X-rays can help assess the state of your cat’s respiratory condition.

How is Feline Calicivirus Treated?

Unfortunately, there is no designated antiviral medication for feline calicivirus, so treating feline calicivirus focuses on managing symptoms, supporting the cat’s immune system, and preventing secondary infections.

Medications

While there is no antiviral specifically targeting FCV, medications from our vet pharmacy can help address complications and improve the cat’s comfort:

• Antibiotics

Antibiotics will be used to treat and manage any secondary infections that come as a result of the calicivirus infection. Different forms of medications will be used depending on which area is affected.

• Pain Relievers

Cats with mouth ulcers may benefit from pain management medications to help them recover and eat normally.

• Anti-Inflammatory Drugs

These medications may be used in some cases to reduce swelling and discomfort, especially if your cat is experiencing lameness or joint pain.

Supportive Care

Supportive care treatments focus on supporting your cat’s recovery. Treatment steps will include:

• Hydration Support

Keeping cats hydrated is important, especially if nasal congestion or oral ulcers have reduced their water intake. In severe cases, intravenous fluids may be necessary.

• Nutritional Support

Cats with oral ulcers may refuse to eat, so offering soft, palatable foods can encourage them to maintain their caloric intake. Warming the food slightly can also make it more appealing.

The Importance of Vaccinating Against Feline Calicivirus

Vaccines are the most important part of your cat’s health when it comes to feline calicivirus. Regular vaccinations are important for protecting and preventing. Vaccination helps prepare your cat’s immune system to recognize and fight off the virus. 

While vaccinated cats can still become infected with FCV, they are much less likely to experience severe symptoms. Vaccinated cats have a stronger defense against the virus, minimizing the effects of the virus and increasing the likelihood of recovery.

Preventing a disease is always more cost-effective than treating it. Treating FCV infections can require expensive veterinary care, hospitalization, and medications. Regular vaccinations are a small, predictable cost compared to the potential expenses of managing an active FCV infection. Plus, vaccination can prevent the spread of the virus. This is especially helpful if your cat frequents daycares and grooming salons since these areas house a lot of cats. 

Conclusion

While feline calicivirus is a dangerous disease, there are steps you can take to reduce the chance of this disease affecting your cats. With regular vaccination against calicivirus, your cat will be able to stay protected and healthy.