Feline Calicivirus Infection in Cats

If your cat starts to show cold or flu-like signs like sneezing, discharge around the eyes and nose, and lack of appetite, contact your veterinarian. A detailed history, physical exam, and bloodwork can help to diagnose the disease. Treatment and prognosis will depend on the severity of the symptoms.

Feline Calicivirus(FCV) infection is a viral infection of the upper respiratory system in cats. It spreads by direct contact with virus containing droplets from an infected cat and contaminated surfaces such as food and water bowls or bedding. If your feline companion becomes infected, you will notice signs like loss of appetite, sneezing, discharge from the eyes and nose, and ulcers on the tongue. Signs can last from a few days to a few weeks depending on the severity of the infection. Kittens tend to be most susceptible to more severe forms, and may develop pneumonia from the viral infection.

Most FCV infections result in an upper respiratory infection, but it can also lead to a limping syndrome or a systemic infection that affects organs throughout the body. General symptoms of infection tend to occur with each form of FCV and may include:

• Lethargy and depression
• Lack of appetite
• Fever

Types

Oral and Upper Respiratory Disease

If your cat becomes infected with the oral and upper respiratory disease form of FCV, symptoms may include:

• Ulcers of the tongue and mouth
• Discharge from the nose and eyes
• Sneezing
• Pneumonia
• Difficulty breathing

FCV-Associated Lameness

In some cases, the virus will cause a thickening of the synovial lining of joints. You may notice symptoms like:

• Lameness
• Difficulty walking
• Swollen, painful joints

FCV-Associated Virulent Systemic Infection

On rare occasions, a cat can become infected with a more virulent strain of FCV. Felines that have this form of the disease will be severely ill, and you may notice signs like:

• Pneumonia
• Skin swelling and ulceration
• Bleeding from the nose and intestine
• Sudden death

All forms of the infection are caused by FCV. This is a virus that is transmitted through the mucous membranes of the eyes, nose, and lining of the eyelids. Once the virus enters the body, it multiplies mainly in the oral and respiratory tracts and causes the upper respiratory signs listed above. If the virus goes beyond the respiratory tract, it may affect the synovial membranes of the joints, leading to the signs of lameness and arthritis.

Very rarely, FCV is able to access other cells and tissues in the body. In this case, the virus attacks vital organs like the liver, pancreas, gastrointestinal tract, and lungs, resulting in all the general symptoms, and also signs of systemic infection like swelling and ulceration of the skin and bleeding from body openings. In very severe cases, the only sign you see will be death.

If you suspect your cat has FCV, contact your veterinarian. Your doctor will collect a detailed history including when you first noticed the signs and whether your feline friend has been in contact with other cats. Following a thorough physical exam to evaluate your cat's health and check all the body systems, your vet may choose to conduct further tests. 

A presumptive diagnosis is possible based on the history and physical. Depending on the severity of the illness, your vet may want to take x-rays to check for signs of pneumonia or run bloodwork to check for signs of organ damage. Treatment can be conducted based on the symptoms. For a definitive diagnosis, the doctor can take swabs of the mucous membranes of the eye or mouth and send them to a laboratory for analysis.

There is no specific treatment for the initial infection with FCV, but your veterinarian may prescribe antibiotics to help prevent or treat secondary bacterial infections. If your cat has associated lameness, antiinflammatories and painkillers may be prescribed. When symptoms are severe, your cat will be hospitalized to provide intravenous fluids, nutritional therapy, and oxygen as needed. 

If the symptoms of FCV infection are manageable, provide nursing care at home. Keep your cat comfortable. You can use a humidifier to make breathing easier. Wipe the the eyes and nose as needed to clear away discharge. If your cat has oral ulcers, use soft food that is gently warmed. 

In most cases, symptoms will last a few days to a few weeks. Pneumonia can become severe and may be life-threatening especially in young kittens. In the case of FCV-associated virulent systemic infection, 50% or fewer affected animals survive.

Follow-up after recovery from the disease depends on the symptoms your cat may have experienced. For cats with pneumonia, your veterinarian may want to conduct a post-infection physical with x-rays to confirm recovery. Most infected cats continue to shed the virus for about 30 days after infection, so you will want to keep your cat isolated from other animals. Some cats can become chronic carriers and may shed the virus long term.

The best way to manage FCV is by vaccination. Kittens should receive 2-3 vaccinations 8 weeks apart, followed by routine booster shots as directed by your veterinarian. The vaccine does not prevent infection, but can reduce the severity of the symptoms.