Felis ISSN 2398-2950

Feline calicivirus test

Contributor(s): Karen Coyne, Alan Radford, Melissa Wallace

Overview

  • The most widely used test is for the presence of live virus by isolation in cell culture. Also available are antigen detection assays, most using immunofluorescence, for detecting virus in tissue scrapings/impressions, eg conjunctival scraping.
  • Alternatively, but less commonly, presence of viral genome may be detected by reverse transcriptase polymerase chain reaction (RT-PCR) PCR (Polymerase chain reaction). This is not widely available as a standard diagnostic test in the UK and has not yet been shown to be as sensitive for divergent strains of FCV Feline calicivirus. Therefore, it is not mentioned further in the routine diagnostic context. However, following isolation, RT-PCR has been used to determine the sequence of FCV strains, which allows for the epidemiological investigation of disease.
  • Prescence of the viral genome may also be detected by real time reverse transcriptase polymerase chain reaction (real time RT-PCR), however, this is not widely available as a standard diagnostic test, although some reports suggest that real time RT-PCR is sensitive to the detection of divergent FCV strains.
  • Tests for serum antibody are also available but are rarely indicated clinically, and are generally restricted to research applications, or in cats without a history of vaccination. They are not considered further.
  • Paired titers that show a rising antibody level are indicative of active infection.

Sampling

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Tests

Methodologies

  • Several types of test are available:
    • Virus isolation in feline cell culture and demonstration of characteristic cytopathic effect. Also antigen detection.
    • Viral genome detection by RT-PCR and real time RT-PCR. Not routinely available.
    • Antibody detection in serum. Usually of little use due to widespread vaccination and high infection prevalence. Paired samples useful in acute infection.

Availability

  • Only certain specialist laboratories.

Validity

Sensitivity

  • Difficult to give a specific sensitivity since isolation is generally accepted as the gold standard test.
  • Providing a good sample is collected and transported rapidly, isolation sensitivity is likely to be very high.
  • Sensitivity of RT-PCR has not been extensively researched but is likely to be lower than virus isolation due to the variable nature of different FCV strains.

Specificity

  • Good. False positives by isolation from an experienced laboratory are extremely unlikely.

Predictive value

  • Positive tests must be interpreted with care when trying to associate infection with clinical disease because of the high prevalence of FCV carriers in the cat population.

Technique (intrinsic) limitations

  • The prevalence of FCV is high in certain cat populations, and many clinically normal cats will be FCV positive.
  • Vaccination does not prevent infection and many vaccinated cats will also shed FCV.

Result Data

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Abd-Edlaim M M, Wilkes R P, Thomas K V, Kennedy M A (2009) Development and validation of a TaqMan real-time reverse transciption-PCR for rapid detection of feline calicivirus. Arch Virol 154(4), 555-560.
  • Radford A D, Dawson S, Wharmby C, Ryvar R & Gaskell R M (2000) A comparison of serological and sequence-based methods for typing feline calicivirus isolates from vaccine failuresVet Rec 146(5), 117-123.
  • Radford A D, Sommerville L, Ryvar R, Cox M B, Johnson D R, Dawson S & Gaskell R M (2001) Endemic infection of a cat colony with a feline calicivirus closely related to an isolate used in live attenuated vaccinesVaccine 19(31), 4358-4362.

Organization(s)

  • For RT-PCR investigation of FCV disease epidemiology contact Small Animal Virology Group, University of Liverpool Veterinary Teaching Hospital, Leahurst, Chester High Road, Neston, S. Wirral, CH64 7TE, UK. Tel: +44 (0) 151 794 6012.


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