Feline Calicivirus (FCV) In Cats

Feline Calicivirus (FCV) is a contagious viral infection that affects cats worldwide. It is a member of the Caliciviridae family and is one of the most common respiratory diseases in felines. FCV can lead to a range of symptoms, from mild to severe, and can pose a significant health risk, particularly to unvaccinated or immunocompromised cats. In this article, we will explore the key aspects of Feline Calicivirus, including its symptoms, treatment, and prevention.

What is Feline Calicivirus in Cats? 

Feline calicivirus (FCV) is a member of the Caliciviridae family and can cause a variety of respiratory and oral symptoms in infected cats. FCV is one of the viruses responsible for feline upper respiratory infections (URIs) and can also lead to other clinical signs such as gingivitis, mouth ulcers, and lameness.

FCV is highly contagious among cats and can be spread through direct contact with an infected cat's saliva, nasal discharge, or ocular secretions. It can also be transmitted indirectly through contaminated objects such as food and water bowls, grooming tools, and bedding. Additionally, FCV can survive in the environment for several days, which makes it relatively easy for cats to become exposed to the virus.

Symptoms of Feline Calicivirus in Cats

FCV can manifest itself in various ways, making it a challenging disease to diagnose based solely on symptoms. Common signs of FCV infection in cats include:

• Oral and Respiratory Symptoms: Cats infected with FCV often develop oral and respiratory issues. These may include ulcers in the mouth, inflammation of the gums, nasal discharge, sneezing, and coughing.

• Eye Problems: Some cats with FCV may experience conjunctivitis (inflammation of the conjunctiva, the membrane covering the eye), leading to eye discharge and redness.

• Lethargy: Infected cats may appear lethargic, lose their appetite, and become dehydrated.

• Joint Pain: A less common but more severe form of FCV can lead to joint pain, lameness, and fever.

• Persistent Infection: FCV can sometimes become chronic, resulting in long-term issues such as gingivitis and stomatitis.

How Do Cats Get Feline Calicivirus?

Cats can contract Feline Calicivirus (FCV) through direct or indirect contact with infected cats or contaminated environments. Here are the primary ways through which cats can become infected with FCV:

• Direct Contact: The most common mode of transmission is through direct contact with an infected cat. This can occur when an uninfected cat interacts with an infected cat that is shedding the virus in its saliva, nasal discharge, or ocular secretions. Common situations where direct transmission may occur include grooming each other, sharing food or water bowls, or engaging in close social interactions.

• Airborne Transmission: FCV can be aerosolized when an infected cat sneezes or coughs, releasing tiny respiratory droplets into the air. Cats in close proximity to an infected cat may inhale these droplets, leading to infection.

• Contaminated Objects: Indirect transmission can happen when an uninfected cat comes into contact with surfaces or objects contaminated by an infected cat's bodily fluids. This can include shared bedding, toys, food and water bowls, and grooming tools. The virus can survive in the environment for several days, making it possible for cats to become infected by touching contaminated surfaces or objects and then grooming themselves.

• Carrier Cats: Some cats may become chronic carriers of FCV, meaning they continue to shed the virus even when they don't show clinical signs of illness. These carrier cats can serve as a source of infection for other cats in the same household or community.

• Asymptomatic Shedding: Cats infected with FCV may shed the virus even before they show clinical signs of illness. This means that seemingly healthy cats can still transmit the virus to others.

How Veterinarians Diagnose Calicivirus in Cats？

The veterinarian will start by conducting a thorough physical examination of the cat. They will assess the cat's overall health, check for clinical signs associated with FCV (such as oral ulcers, nasal discharge, sneezing, coughing, lameness, and conjunctivitis). The presence of clinical signs consistent with FCV, especially in conjunction with a history of potential exposure to the virus, may raise suspicion of FCV infection.

To confirm the diagnosis, veterinarians may collect samples from the cat to test for the presence of the virus:

• Oral and Nasal Swabs: Swabs may be taken from the cat's mouth or nose to collect samples of oral and nasal secretions. These samples can be tested for the presence of FCV genetic material using polymerase chain reaction (PCR) tests.

• Conjunctival Swabs: If the cat has eye symptoms (conjunctivitis), swabs from the conjunctiva (the lining of the eye) may be collected for testing.

If a specific diagnosis is required, ocular or oral swabs can be submitted to a veterinary laboratory where the virus can be grown in culture or, more commonly, detected by PCR (a molecular technique for detecting the genetic material of the virus).

Treatment and Management of FCV Infections

The treatment and management of Feline Calicivirus (FCV) infections focus on supportive care to alleviate the clinical signs and reduce the spread of the virus. There is no specific antiviral medication to treat FCV, so the goal is to manage the symptoms and provide comfort to the affected cat. Here are the key aspects of treating and managing FCV infections:

1. Nutritional Support

Cats with FCV may have reduced appetite due to mouth ulcers and other symptoms. It's essential to encourage the cat to eat by offering palatable, soft, and easily chewed foods. In instances of severe cases, mouth ulcers are treated with oral sprays, and feeding through a syringe may be necessary.

Puainta® Spray for Dog/ Cat Mouth Ulcers and Mouth Cleaning Helps repair oral mucosa Helps heal mouth wounds Relieves pain, redness and swelling Can be licked; safe and not irritating

2. Fluid Therapy

Maintaining proper hydration is crucial, especially if the cat has a fever or is not eating or drinking well. Fluid therapy may be administered by a veterinarian to prevent dehydration.

3. Pain Management

Cats with FCV may experience joint pain, which can be painful. Pain management medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), may be prescribed to alleviate discomfort.  The active ingredients in common feline NSAIDs include:

• Meloxicam

• Robenacoxib

4. Antibiotics

Secondary bacterial infections can occur in cats with FCV due to the virus weakening the immune system. Antibiotics may be prescribed if bacterial infections are suspected or confirmed. Common antibiotics prescribed for cats to treat bacterial infections include:

• Amoxicillin: An antibiotic that is effective against a wide range of bacteria and is commonly used for various infections.

• Clindamycin: Used to treat skin and dental infections, as well as certain respiratory and bone infections.

• Cephalexin: Often prescribed for skin infections, urinary tract infections, and respiratory infections.

• Enrofloxacin: Effective against a broad spectrum of bacteria and used for urinary tract infections, respiratory infections, and more.

• Doxycycline: Used for respiratory infections, tick-borne diseases, and certain skin infections.
  Azithromycin: Prescribed for respiratory infections, including upper respiratory infections in cats.

5. Eye Care

For cats with conjunctivitis (inflammation of the eyes), the veterinarian may prescribe eye drops or ointments to reduce inflammation and manage any secondary infections.

For the treatment of bacterial conjunctivitis in cats and dogs, neomycin eye drops for dogs and cats can reduce the harmful effects of bacterial conjunctivitis, and early use of the drug can control the development of the disease and reduce eye congestion and photophobia, and other uncomfortable manifestations.

6. Antiviral Medications

In some cases, veterinarians may consider using antiviral medications, such as famciclovir, in an off-label manner to help manage FCV infections. However, the effectiveness of these medications may vary.

7. Vaccination

Vaccination is a key preventive measure against FCV. Cats should receive their initial vaccinations as kittens and then receive booster shots as recommended by a veterinarian. Vaccination can reduce the severity of clinical signs if a vaccinated cat is exposed to the virus.

Vaccination for FCV is important for all cats. Two or three injections are recommended in kittens, starting at around 8 weeks of age. Cats should receive a booster at a year of age, and after that should receive further booster vaccines every 1-3 years.

Supportive care measures are also recommended for cats infected with calicivirus. These include:

• Wiping away nose and eye discharge. 

• Feeding extra tasty food to stimulate appetite.

• Environmental humidification (steam from a hot shower) to relieve nasal and airway congestion.

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How Long Do Cats Live with Feline Calicivirus?

Cats with mild FCV infections, especially those that primarily manifest with mild respiratory symptoms or oral ulcers, often recover fully with appropriate care within a few weeks. These cats may not experience any long-term effects of the virus, and their lifespan should not be significantly affected.

In more severe cases of FCV, especially when the virus leads to complications such as pneumonia, chronic gingivostomatitis (severe mouth inflammation), or joint problems (FCV-associated arthritis), the prognosis may be less favorable. Some cats may experience chronic health issues that affect their quality of life, and this could potentially shorten their lifespan.

Feline Herpesvirus and Feline Calicivirus

Feline Herpesvirus (FHV) and Feline Calicivirus (FCV) are two common viruses that contribute to Feline Upper Respiratory Infections (URIs) and related health issues in cats. 
Both FHV and FCV are common pathogens in cats and often occur together in cases of feline respiratory disease. These viruses can lead to mild to severe respiratory symptoms, and in some cases, they can cause more severe complications, such as pneumonia or chronic gingivostomatitis (severe mouth inflammation).

Related: Cat Herpes: FVR and FHV-1 Symptoms and Treatments

Feline Infectious Respiratory Disease and Feline Caliciviruses in Cats

FIRD refers to a group of highly contagious upper respiratory infections in cats, similar to the common cold in humans.
It is caused by a combination of several viral and bacterial pathogens, with two primary viruses being involved: Feline Herpesvirus (FHV) and Feline Calicivirus (FCV).
Cats with FIRD typically exhibit symptoms such as sneezing, nasal discharge, coughing, conjunctivitis, and sometimes oral ulcers.
FHV and FCV are often found together in cases of FIRD, making them the main culprits behind the syndrome.

Lameness in Cats and Feline Caliciviruses in Cats 

Lameness in cats, which refers to limping or difficulty in walking, can be associated with FCV infection in some cases. FCV can cause lameness due to joint inflammation, a condition known as "limping syndrome" or "FCV-associated arthritis." Lameness typically affects one or more joints and can be accompanied by swelling and pain.

FAQs

Can Calicivirus Be Cured?

Calicivirus itself cannot be completely cured because it is a viral infection. However, the symptoms of the infection can be treated and managed. Cats with calicivirus can recover with supportive care, which may include providing fluids, antibiotics to treat secondary bacterial infections, pain medication, and nutritional support. Most cats with calicivirus recover within a few weeks, although some may become chronic carriers of the virus, meaning they continue to shed the virus even after recovering from the clinical signs.

Is Calicivirus Deadly?

In most cases, calicivirus is not deadly, and many cats recover from the infection. However, severe cases can be life-threatening, especially in young kittens, elderly cats, or those with weakened immune systems. The virus can cause pneumonia or other complications in such cases. Additionally, the virus can be more severe if there are concurrent health issues or if the cat is exposed to a particularly virulent strain of the virus.

Can A Cat with Calicivirus Live with Other Cats?

Cats with calicivirus should be isolated from other cats to prevent the potential spread of the virus. Calicivirus is highly contagious among cats and can be transmitted through direct contact, as well as through sneezing and coughing. It's important to keep an infected cat separate from healthy cats, especially in a multi-cat household or in a shelter environment, to prevent the virus from spreading.

Is Calicivirus Contagious to Humans?

No, FCV is not infective to humans. 

Conclusion

Feline Calicivirus (FCV) is a contagious and potentially serious disease that can affect cats of all ages. Understanding its symptoms, transmission, treatment options, and preventive measures is essential for cat owners. Vaccination is the cornerstone of FCV prevention, along with good hygiene practices and early intervention if your cat exhibits any signs of illness. By taking these steps, you can help protect your feline companions from this common viral infection and ensure their well-being. Always consult with your veterinarian for guidance on the best approach to managing FCV in your cats.