The Feline Calicivirus (FCV) is a highly contagious virus that causes upper respiratory infection in cats. Together with the Feline Herpes Virus, FCV is the cause of nearly all upper respiratory infections in cats. The virus has a more dangerous and severe form known as FCV-associated virulent systemic disorder (FCV-VSD). FCV has several other strains due to its unique ability to mutate very quickly. Certain strains of FCV are more pathogenic than others which may explain why different cats get infected with different degrees. Its ability to mutate quickly also explains why after years of vaccination, the disease persists in cat populations.
How is Feline Calicivirus (FCV) Infection Transmitted?
FCV is highly contagious meaning it spreads very easily from one cat to another. Fortunately, the virus does not affect humans. Due to how contagious it is, FCV is very common in shelters and pet stores where up to half of the cats may be carriers for the virus. Most cats that suffer from FCV shed the virus for 2 to 3 weeks, that is to say, they can spread it to other cats for this long. Some cats can even carry the virus for months after infection. Some of the ways FCV can be spread and contracted include:
- Direct contact with body fluids of an infected cat. Such fluids include saliva, nasal, and ocular discharge
- Aerosolized particles from sneezing
- Sharing of bowls and bedding
- Contact with a human that has previously handled an infected cat
FCV can survive on surfaces for months. It is therefore important to clean and disinfect all surfaces especially in environments with many cats.
How is Feline Calicivirus Infection Diagnosed?
Diagnosis of the FCV is usually not needed. If a cat has signs and symptoms of upper respiratory tract infection, the vet will not need a confirmatory diagnosis for Feline Calicivirus infection. This is because FCV and herpesvirus cause nearly all upper respiratory infections in cats. It is therefore assumed FCV is present if a cat has the signs and symptoms of upper respiratory infections. On the rare occasion that a confirmatory test is required, the vet will take swabs of the cat’s mouth, nose, and eyes. The swabs will then be sent to a lab for testing. In the lab, testing is either done by growing the virus in culture or the PCR method. The PCR method is the preferred method for testing in labs. It involves testing a sample for the presence of genetic material that is unique to the Calicivirus. If the material is detected, then it is confirmed that the cat indeed has the virus. False results may be observed in some cats for example a false positive may be seen in a recently vaccinated cat. A false positive may also be seen if a cat has previously been exposed and recovered from feline calicivirus infection. Tests cannot distinguish between the regular and severe forms of feline calicivirus (FCV-VSD). To make the distinction, the pet owner has to critically observe the cat for any unusual signs and symptoms.
What are the Signs and Symptoms of FCV?
The specific signs and symptoms a cat with feline calicivirus will differ according to the strain of FCV acquired. There are, however, some signs and symptoms that are common to all cats with feline calicivirus:
- Upper respiratory infection (URI). This is the most common and defining sign of the feline calicivirus. The URI signs look very similar to those of a cold accompanied by sneezing, nasal discharge, nasal congestion, and ocular discharge. The URI may last anywhere from a week to months. If left untreated, the URI may progress into pneumonia.
- Fever. Similar to any infection, the cat’s temperature will go up as the body’s immune system tries to fight off the virus.
- Oral ulcers. In the early stages of calicivirus infection, cats experience inflammation of the mouth lining and tongue. Some cats may even develop gingivitis (inflammation of the gums).
- Lameness. FCV may cause limping or lameness in cats by inducing inflammation in the joints. The joints become too painful to stand on causing the cat to walk with a limp.
- Loss of appetite. Cats may eat less during FCV infection. The ulcers on the lining of the mouth and tongue may also make eating difficult.
- Lethargy. Your cat may not be as playful and active
- Weight loss. Some cats may lose weight during infection due to reduced food intake
- Miscarriage. Pregnant cats may suffer a miscarriage.
While some of the signs and symptoms of FCV seem alarming, they are usually mild and tend to resolve with proper care and treatment in as little as a week. As for FCV-VSD, the signs are more severe and are often life-threatening. Some of the signs and symptoms of FCV-VSD include:
- Swelling of the face and limbs
- Very high temperature
- Liver damage
- Bleeding from the nose and the gut lining
- Jaundice (yellowing of the skin) due to liver damage
FCV-VSD is very tough on cats and over 60% of cats that get it die.
Limping Syndrome and Feline Calicivirus
You may observe a change in the way your cat walks if she has a calicivirus infection. Lameness is a common sign in cats with FCV. It is especially common among kittens. Just like upper respiratory tract infection, lameness is heavily associated with the feline calicivirus. The defining characteristics of lameness in cats with FCV are:
- Stiffness in the joint
- Pain in the joints on touch
- Increased sensitivity in the joints
- Reluctance to move
How FCV can Affect the Joints
The limping syndrome observed in cats with calicivirus infection can be attributed to the virus’s effect on the joints. In cats with FCV or FCV-vaccinated cats, calicivirus proteins can be seen in their synovial space. The synovial space is the space in the joints. Naturally, when the body recognizes a foreign object, in this case the viral proteins, it elicits an immune response. Antibody production and inflammation are some of the actions the body takes against the virus. This inflammation intended to work against the virus is what causes the joint pain in FCV infection. The degree of inflammation varies according to the strain of FCV.
Treatment and Management of FCV
Even though feline calicivirus has been known to affect cats for decades and an effective treatment has not yet been developed. The best that can be done for a cat with FCV is to provide sufficient care as the disease resolves. Antibiotics are given to prevent the development of secondary infections. Cats with FCV usually recover at home even without treatment but hospitalization may be needed in more severe cases especially in kittens. Hospitalized cats are supported to prevent dehydration and given nutrition support to prevent weight loss. They may also be nebulized or steamed to unblock their nasal passages and improve their sense of smell and taste. Cats with FCV should be isolated from their healthy counterparts to reduce the risk of transmission.
Vaccination Against FCV
Thanks to advancements in science, your cat may not have to deal with the ordeal of FCV. You can get your cat vaccinated against FCV and reduce her chances of acquiring the disease. The American Association of Feline Practitioners (AAFP) recommends that all kittens should be given two core vaccines; the rabies vaccine and the FVRCP vaccine. The FVRCP vaccine is a combination of 3 vaccines:
- Feline Panleukopenia (FPV)
- Feline Herpesvirus- 1 (FHV)
- Feline Calicivirus (FCV)
FCV vaccination does not guarantee that your cat will not get the virus but it greatly reduces the severity of the signs and symptoms. It is highly recommended that you vaccinate your cat against FCV before 8 weeks of age. It is advisable to get the shot as soon as possible because kittens are especially affected by FCV. Vaccination should ideally be done at 6 to 8 weeks and booster shots given every 2 to 3 weeks until 16 weeks. Even older cats need FCV vaccination to reduce the severity of symptoms. Cats older than 16 weeks should get two doses about 3 to 4 weeks apart. Cats need to get a booster shot every three years. If your cat has previously suffered from FCV, it does not mean she cannot get it again. Some variants of the virus have different antigens (antigens are surface markers by which cells are identified. If the body cannot recognize an antigen it cannot prevent infection).
Limping After FCV Vaccination
While vaccination is great in the long-term, it may not be as pleasant immediately after the shot. A vaccine is simply a milder version of a disease-causing pathogen, in this case, FCV. When your cat is given an FCV shot, the body cannot distinguish between a real infection and a vaccine. The body will therefore respond to the vaccine as it would the real infection. The body will produce antibodies against the virus which is the effect we are looking for when we vaccinate. However, the body will also elicit an inflammatory reaction in an attempt to destroy the virus (vaccine). This is why, after vaccination against FCV, you may notice your cat develop a slight limp. This is no reason to be scared of FCV vaccination. The limp will resolve on its own within a couple of days. Cats with low immunity may experience more severe reactions. The limp usually requires no intervention by the owner but some relief can be provided to ease the cat’s discomfort. You may give pain medication if approved by your vet. Applying a warm towel to the joints may also provide some relief.
How You Can Help Your Cat with FCV
If your cat has caught FCV, you should not underestimate your role in her recovery. In fact, since there is no known treatment for the disease, your care as an owner may be the defining factor in how fast your cat recovers. Some of the ways you can support your cat with FCV include:
- Wipe the cat’s eyes and nose. Keep the cat free of discharge to promote recovery and minimize the risk of developing secondary infections.
- Press the nose gently with warm gauze to unblock the nasal passage.
- Steam the cat. You can do this by allowing steam to accumulate in the shower and putting your cat inside for 5 to 10 minutes
- Provide food with strong flavors to entice the cat to eat
- You may have to feed your cat if her mouth ulcers are very bad
- Seek the help of a vet if your cat’s signs and symptoms get worse for example if your cat goes 48 hours without eating or drinking.
Cats with FCV-VSD should always be hospitalized.
Our Final Thoughts
It is very normal for cats to develop limping after getting infected with the feline calicivirus. It is equally normal after vaccination against the virus. The first step in protecting your cat against FCV is vaccination. If your feline gets infected, proper care is essential for her recovery. Pain medication and pressing with a warm cloth can be used to help with the lameness. Other symptoms can be managed by methods like steaming, cleaning discharge off the cat, and providing flavorful foods.
Frequently Asked Questions
Why is my cat limping all of a sudden?
The most common cause of limping in cats is soft tissue injury. If your cat has no injury, she may have an FCV infection. FCV is usually accompanied by other clinical signs like nasal discharge and fever.
What are the signs and symptoms of Feline Calicivirus?
A cat with FCV will develop the following signs and symptoms; upper respiratory disease, fever, oral ulcers, lameness or limping, and lethargy.
Why is my cat limping but not in pain?
The most likely cause of painless limping in cats is FVC.
What is limping kitten syndrome?
Limping kitten syndrome is a condition in which a kitten has difficulty walking due to an infection by the feline calicivirus.