Diagnosis of FCV
Calicivirus is usually diagnosed on the basis of clinical symptoms and the cat's medical history (i.e., the cat's vaccination status and past exposure). Blood tests usually are not informative. Other laboratory tests may be conducted to isolate the virus and confirm the diagnosis. These diagnostic tests include the following:
- Immunofluorescent assays of lung tissuespecial proteins labeled with a fluorescent chemical to detect the presence of FCV antigens, proteins the immune system manufactures to fight the virus
- Oropharyngeal (throat) cultures
- Serum testingto identify paired serum samples, a rise in titer over the course of 2 weeks is considered a positive diagnosis
- X-rayto detect pneumonia
FCV & Differential Diagnosis
Clinical symptoms of FCV are similar to those of other feline upper respiratory infections, but cats with calicivirus are more likely to have ulcers in their mouth or on their paws.
Cats with rhinotracheitis virus sneeze more, have more eye discharge and inflammation, and are more likely to have pneumonia. Cats with feline chlamydiosis have chronic conjunctivitis (discharge, pain, and swelling of the eye caused by inflammation of the membrane lining the eyelid).