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Feline Calicivirus Infection in Cats



Feline calicivirus infection is a common respiratory disease in cats. The virus attacks the respiratory tract -- lungs and nasal passages -- the mouth, with ulceration of the tongue, the intestines, and the musculoskeletal system. It is highly communicable in unvaccinated cats, and is commonly seen in multicat facilities, shelters, poorly ventilated households, and breeding catteries. 


While vaccination against the calicivirus is strongly advised, vaccinations have failed to decrease the prevalence of the disease. This infection can occur in cat of any age, but young kittens older than six weeks have been found to be most susceptible.


Symptoms and Types


The following symptoms typically present themselves suddenly:


  • Loss of appetite (anorexia)
  • Eye discharge
  • Nasal discharge
  • Development of ulcers on tongue, hard palate, tip of nose, lips or around claws
  • Pneumonia
  • Difficult breathing after development of pneumonia
  • Arthritis (inflammation of joints)
  • Lameness
  • Painful walk
  • Fever
  • Bleeding from various sites




Cats typically acquire feline calcivirus (FCV) after coming into contact with other infected cats, such as in a shelter, cattery, or boarding facility. But because FCV is resistant to disinfectants, cats may come into contact with the virus in almost any environment. Lack of vaccination or improper vaccination is thought be an important risk factor, as well as a lowered immune response due to pre-existing infections or diseases.





You will need to give your veterinarian a thorough history of your cat's health, onset of symptoms, and possible incidents or conditions that might have led to this condition. Your veterinarian will perform a thorough physical exam to evaluate all body systems along with the overall health of your cat. A complete blood profile will also be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. The results of these tests, however, are often non-specific and do not provide consistent findings for an initial diagnosis.


The more reliable diagnostic test involves identifying a buildup of FCV antibodies. These antibody tests can be used to detect and measure the levels of feline calcivirus antigen and/or antibodies corresponding to the viral antigen (feline calcivirus). A more advanced test that may be used involves growing the isolated viruses under controlled conditions using a technique called cell culture.


Diagnostic imaging can be used to determine any damage to the lungs; chest X-rays may show changes in the lung tissue, including consolidation of lung tissue in cats with pneumonia.



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