Feline Calicivirus: More Than a Cold

A new feline companion in your family is an exciting time, but pet owners must remember a lot about their care. Cats’ independent nature can make them seem as though they do not require a lot of time and energy. However, cats require regular veterinary care, in addition to good nutrition, and proper mental and physical exercise. The first few months are critical to ensure that your new cat is properly protected from common infectious diseases and viruses. Young cats and cats with chronic diseases are at increased risk for respiratory problems because their immune systems are not fully developed or are weakened from disease. Feline calicivirus (FCV) is a common virus affecting cats and our Animal Emergency Care team describes FCV signs, treatment, and prevention.

What is feline calicivirus in cats? 

FCV is a highly contagious RNA virus affecting cats that is a significant cause of upper respiratory and oral infections. In fact, FCV causes more than 50 percent of cat respiratory infections. This virus most commonly occurs in multi-cat environments, such as shelters, breeding colonies, or pet stores. This virus readily mutates and vaccinations may not fully prevent new strains. However, most cats who contract FCV will recover. In rare cases some cats may contract a severe case of FCV-associated virulent systemic disease (FCV-VSD), which is fatal in 60 percent of cases. FCV spreads through direct contact with saliva, eye discharge, nasal discharge, or aerosolized sneeze droplets from infected cats. Common ways a cat may become infected include:

  • Direct contact with an infected cat
  • Kittens born to a FCV-carrier mother
  • Sharing food bowls, water bowls, or litter trays with an infected cat
  • Contact with a human who recently interacted with an infected cat
  • Contact with contaminated environments and objects, including bedding or grooming tools

Feline calicivirus signs in cats

FCV signs in cats are similar to other infections that may cause an upper respiratory infection. Severity will depend on the viral strain type, and the strength of the infected cat’s immune system. Young cats, kittens, and cats who have other chronic conditions have an increased risk for more severe FCV signs. Signs may occur between 2 and 14 days following the initial infection and can persist for more than six weeks. Cats who contract FCV may shed the virus for more than three weeks following an infection, and some pets may become long-term FCV carriers. Signs may include:

  • Uncontrollable, sudden sneezing attacks 
  • Nasal congestion
  • Excessive eye blinking and squinting
  • Mouth and tongue ulcers
  • Inflamed gums
  • Drooling
  • Clear, yellow, or green nasal and eye discharge
  • Redness around and in the eye
  • Loss of smell
  • Fever
  • Lethargy
  • Loss of appetite
  • Enlarged lymph nodes
  • Painful joints

Cats who contract FCV-VSD may show the following signs:

  • High fever
  • Swelling of the head and legs
  • Crusting sores around the face and mouth
  • Hair loss around the nose, ears, eyes, and foot pads
  • Skin yellowing

Feline calicivirus diagnosis and treatment in cats 

Your cat needs a veterinary examination if they are showing FCV or FCV-VSD infection signs, which are similar to other respiratory infections including feline viral rhinotracheitis. Ensure you inform your veterinarian if your cat has interacted with a potentially infected kitten or adult cat, or if they have recently been adopted from a shelter. Diagnosis is based on your cat’s medical history, clinical signs, and potential FCV exposure history. A PCR test to look for FCV DNA in samples of an infected cat’s eye, nose, or throat will provide a definitive diagnosis. Other diagnostics tests may include a complete blood count to check for secondary infections or an associated disease and a serum biochemistry test to evaluate organ function. Specialized eye tests to check for corneal ulcerations and dry eye may also be recommended. An X-ray may be recommended to check for joint swelling or pneumonia. 

No treatment can stop an FCV infection, although cats who receive immediate veterinary care have a good prognosis. Most pets will recover following at-home supportive care and treatments, including keeping their nose and eyes clean. Kittens or adult cats with severe signs or cats who have FCV-VSD may require hospitalization. Treatments may include:

  • Intravenous fluids to prevent dehydration from excess nasal or eye discharge
  • Antibiotics to prevent secondary bacterial infections
  • Decongestants 
  • Oxygen therapy 
  • Topical eye medications
  • Antiviral medications
  • Non-steroidal anti-inflammatory medications to decrease fever and alleviate any oral ulcer or joint pain
  • L-lysine supplements for immune system support
  • Environmental humidification or nebulization
  • Specialized diet   

Financial options for your cat’s feline calicivirus treatment  

FCV often requires treatment for several weeks in addition to multiple follow -up appointments. Cats with severe cases may require an extended hospital stay, and such care can result in a large veterinary bill. However, several payment options are available to cover treatment costs including:

  • Pet health insurance such as Trupanion which will ensure you can cover the costs for your pet’s emergency FCV treatment 
  • Care Credit and Scratch Pay which allow payments to be spread out over longer periods
  • Pet health savings accounts or short-term loans offered by most financial institutions

Feline calicivirus prevention in cats

Vaccinating your cat when they are young is the best prevention against a severe FCV infection. The FVRCP vaccine is a core cat vaccine that provides protection against FCV and other dangerous respiratory agents. FCV is a mutating virus (i.e., vaccinated cats can still be infected), but disease severity will be greatly reduced, and some infected cats may never show signs. Do not let your cat outside or around other cats or people with cats until they are fully vaccinated against the virus. FCV can survive in the environment for extended periods, so ensure you use diluted bleach to clean areas where an infected cat was present. Use hot water and detergent to clean an infected cat’s bedding. 

Ensure your cat is vaccinated by your family veterinarian to prevent a severe FCV infection. If your cat is showing FCV signs after hours, bring them to Animal Emergency Care for immediate care. #AECprevents





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