Feline Calicivirus in Cats: Causes, Symptoms, and Treatment

Feline calicivirus (FCV) is a common viral infection affecting cats of all ages and breeds. It is particularly prevalent in environments where cats live in close contact, such as multi-cat households, shelters, and boarding facilities. While some cats develop only mild respiratory signs, others experience persistent oral pain, difficulty eating, and chronic inflammation, which can significantly impact their overall health and quality of life.

Feline Calicivirus in Cats

Because early signs of FCV may appear mild, many cases are recognised only after the disease has progressed. Understanding how this virus behaves helps cat owners seek veterinary care early and manage the condition more effectively.

What Is Feline Calicivirus (FCV)?

Feline calicivirus is an RNA virus belonging to the Caliciviridae family. It is commonly associated with feline upper respiratory disease but is also a major cause of chronic inflammatory conditions of the mouth, including:

• Gingivitis

• Stomatitis

• Recurrent mouth and tongue ulcers

• Feline Chronic Gingivostomatitis (FCGS)

Unlike short-term infections, FCV may persist in the body and continue to trigger inflammation, particularly in adult cats and those with weakened immune systems.

How Calicivirus Spreads Among Cats

FCV spreads easily through:

• Direct contact with infected cats

• Saliva, nasal discharge, and eye secretions

• Shared food bowls, litter trays, bedding, and grooming tools

The risk of transmission is highest in shelters, catteries, and multi-cat homes. Some cats become long-term carriers, shedding the virus even when they appear healthy.

Common Symptoms of Calicivirus in Cats

Early or General Symptoms

• Fever

• Reduced activity or lethargy

• Sneezing or nasal discharge

• Reduced appetite

Oral and Dental Symptoms

As the disease progresses, oral involvement often becomes the most prominent feature. Cats may develop:

• Swollen or bleeding gums

• Painful ulcers on the tongue, cheeks, or gums

• Excessive drooling

• Persistent bad breath

• Difficulty chewing or swallowing

Cats experiencing oral pain may approach food but stop eating, leading to weight loss and frustration.

Limping Associated With FCV

Some cats—particularly kittens—may develop temporary joint pain and limping, often referred to as limping calici. Veterinary assessment is recommended to rule out other causes and provide appropriate care.

Severe or Systemic FCV

In rare cases, virulent systemic feline calicivirus (VS-FCV) may occur. This severe form can cause facial or limb swelling, high fever, and involvement of internal organs, and it requires immediate veterinary attention.

Feline Calicivirus in Kittens

Kittens are more vulnerable due to immature immune systems. Symptoms can worsen rapidly, making early veterinary assessment essential when signs such as oral ulcers, limping, or lethargy appear.

How Veterinarians Diagnose FCV

Veterinarians diagnose FCV using a combination of:

• Physical and oral examination

• Review of medical history and living environment

• PCR testing to detect viral genetic material

• Exclusion of other infections, such as feline herpesvirus

Assessment of disease severity and chronic inflammation helps guide treatment planning.

Managing Feline Calicivirus in Cats

Managing FCV—especially in cats with oral disease—requires a targeted approach that addresses viral activity, inflammation, and pain. Veterinary care may combine supportive treatment with antiviral-based options, depending on disease severity.

Antiviral Treatment Options for FCV

For cats diagnosed with FCV-associated disease, antiviral formulations may be used under veterinary supervision as part of a long-term management plan.

CaliciX™ (15 mg EIDD-1931)

CaliciX™ is an oral antiviral capsule formulated to support cats with moderate to advanced FCV-associated oral disease.

It may be included in veterinary-guided treatment plans for:

• Chronic gingivitis and stomatitis

• Oral and tongue ulcers related to FCV

• Persistent mouth inflammation causing pain or difficulty eating

CaliciX™ is intended to support ongoing management, particularly in cats experiencing recurrent or chronic FCV symptoms.

CaliciX™ Max (30 mg EIDD-1931)

CaliciX™ Max is a higher-strength antiviral formulation intended for severe, refractory, or high-viral-load FCV cases, where standard-strength therapy may be insufficient.

Veterinary-directed use may be considered in advanced presentations such as:

• Severe Feline Chronic Gingivostomatitis (FCGS)

• Deep lingual ulceration or extensive oral lesions

• Virulent systemic feline calicivirus (VS-FCV)

The higher strength allows greater antiviral exposure with fewer capsules when dosing is determined by a licensed veterinarian.

Important Veterinary Guidance

• CaliciX™ and CaliciX™ Max are not substitutes for veterinary diagnosis or professional care

• Dosage, duration, and suitability must be determined by a licensed veterinarian

• Clinical response varies between individual cats

• Supportive care—including pain management, nutritional support, dental care, and treatment of secondary infections—remains essential

Preventing Calicivirus in Cats

Risk reduction strategies include:

• Core vaccinations

• Reducing stress in multi-cat environments

• Maintaining good hygiene and disinfection

• Isolating infected cats when possible

Vaccination may not fully prevent infection but often reduces disease severity.

When to Seek Veterinary Care

Consult a veterinarian if your cat shows:

• Persistent drooling or mouth pain

• Difficulty eating or swallowing

• Weight loss

• Limping or fever

• Chronic oral inflammation

Early veterinary involvement improves comfort and long-term outcomes.

Key Takeaway

Feline calicivirus is more than a mild respiratory infection—it can cause lasting oral pain and chronic inflammation. With early recognition, veterinary guidance, and appropriate management—including antiviral support when indicated—many cats can maintain a better quality of life.

If you suspect FCV, seek professional veterinary advice promptly.

Free Consultation if Your Cat Is Affected by Feline Calicivirus (FCV)

If your veterinarian suspects or diagnoses your cat with Feline Calicivirus (FCV)—especially when symptoms such as mouth ulcers, excessive drooling, difficulty eating, or chronic oral inflammation are present—you don’t have to navigate this alone.

The BasmiFIP India team is available to help you better understand your cat’s condition and discuss veterinary-guided FCV management options based on educational resources and clinical experience.

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