What is Feline Calicivirus (FCV)?
FCV is highly contagious and can cause acute oral issues and upper respiratory infections. It is one of the most common pathogens responsible for feline infectious upper respiratory diseases and may even trigger stomatitis.

The Relationship Between Calicivirus and Stomatitis
FCV ≠ Stomatitis ≠ Full-Mouth Tooth Extraction!
Not all cats infected with FCV will develop stomatitis. Some cats can completely clear the virus on their own. While there is a risk, it does not mean it will inevitably happen.
Cats testing positive for FCV should pay extra attention to oral hygiene, brush their teeth regularly, and maintain good oral health.

Symptoms of Feline Calicivirus
FCV has multiple strains with varying virulence, leading to different clinical manifestations.

Main Symptoms:

·       Drooling

·       Sneezing

·       Eye discharge

·       Coughing and other upper respiratory infection signs

·       Fever

·       Rhinitis (inflammation of the nasal mucosa)

·       Lameness (virus-induced synovitis)

·       Oral ulcers (most common)

·       Gingivitis

·       Pneumonia (may develop with more virulent strains)

Transmission Routes of Feline Calicivirus

1.     Sick Cats
During the acute phase, infected cats can shed large amounts of the virus, contaminating utensils, floors, and objects, or directly transmitting it to other cats.

2.     Asymptomatic Carrier Cats
These cases usually result from acute infections. Although clinical symptoms disappear, the cats can still shed the virus long-term, making them the most critical and dangerous sources of transmission.

3.     Direct Contact
The most common mode of infection is direct transmission from an infected cat. The virus replicates in respiratory and oral tissues and spreads through oral, ocular, and nasal secretions, as well as urine and feces.

4.     Indirect Contact
Contaminated food bowls, litter trays, floors, bedding, and caregivers can also spread the virus.

Preliminary Diagnosis of Feline Calicivirus
In most cases, FCV is initially diagnosed based on the symptoms mentioned above. Since multiple viruses can cause feline respiratory diseases with similar symptoms, it can be confusing for pet owners to identify on their own.

A Simple Differentiation Method:

·       If oral ulcers (with nasal involvement) are present, FCV is the most likely cause.

·       If corneal ulcers (involving the eyes) are present, feline herpesvirus (commonly known as feline viral rhinotracheitis) is the most likely cause.

How to Prevent Infection?

1.     Vaccination
The FVRCP vaccine (feline viral rhinotracheitis, calicivirus, and panleukopenia) includes FCV vaccination, which can reduce symptoms by 60–75% but does not provide complete immunity.
However, most fully vaccinated cats will no longer develop oral diseases, showing only mild, short-term symptoms like sneezing, tearing, or respiratory infections.

2.     Isolation
Isolate infected cats to reduce the risk of transmission to others.

3.     Disinfection
Since FCV is highly resistant, common disinfectants are often ineffective. Chlorine-based disinfectants, such as a 1:32 dilution of 5% bleach, are recommended for thorough environmental disinfection.

For FCV detection, Shanghai YaoshuolingTechnology Co., Ltd,a specialist in veterinary diagnostic reagents, has developed two diagnostic kits based on ELISA and PCR technologies, catering to different clinical scenarios. The ELISA-based FCV test kit offers rapid results in about 15 minutes, while the PCR-based kit provides higher accuracy. Veterinarians can choose the appropriate diagnostic method based on clinical needs to better guide disease prevention and treatment.