Felis ISSN 2398-2950

Viral-induced upper respiratory tract disease

Synonym(s): cat flu, URTD

Contributor(s): Severine Tasker, Albert Lloret

Introduction

  • Cause: most cases caused by feline herpesvirus (feline viral rhinotracheitis) Feline herpes virus: feline rhinotracheitis virus (FHV) or feline calicivirus (FCV) Feline calicivirus.
  • Signs: depression, anorexia, pyrexia, mucopurulent oculonasal discharge, sneezing, oral ulcerations.
  • Diagnosis: clinical signs, virus isolation, PCR.
  • Treatment: supportive and symptomatic, antibiotic therapy for secondary bacterial infection, antivirals in some cases.
  • Prognosis: usually good for recovery although occasionally severe disease which can be fatal. Latent (FHV) and chronic (FCV) infections may occur, either subclinical or associated with chronic clinical signs. 

Pathogenesis

Etiology

Predisposing factors

General

Pathophysiology

  • Viral infection   →   replication, epithelial necrosis, neutrophilic inflammation   →   clinical signs.
  • Naso-oral FHV infection   →   replication in nasopharynx, tonsils, conjunctivae, cornea, occasionally skin, rarely mouth and lungs, rarely transient viremia   →   clinical signs   →   transported via nervous system   →   becomes latent in nervous tissue (trigeminal ganglia)   →   can be reactivated and shed 1 week after stress.
  • Naso-oral FCV infection   →   replication in mouth, upper respiratory tract and occasionally lungs, viremia   →   clinical signs   →   virus then persists in tonsils and oropharyngeal tissue for variable period of time (in some cats permanently).
  • Secondary bacterial infection is common and may be severe or generalized in immunocompromized or young cats.
  • Supportive treatment is important to limit severity of general disease.
  • Fatalities can occur in young debilitated cats, immunosuppressed cats (by retroviral infections or drugs) and with virulent variants of FCV causing acute virulent systemic disease.
  • Permanent damage to mucose and turbinate bones may result in chronic signs of disease   →    recurrent or chronic rhinitis or rhinosinusitis.

Timecourse

  • Incubation 1-14 days.
  • Signs resolve within 1-3 weeks.
  • Carrier cats result from infection with both FCV and FHV.
  • With FCV, carriers excrete virus continuously for variable amount of time (most for more than 30 days and a few for many years or life-long) following acute infection. 
  • With FHV, carriers are latently infected for life following acute infection (probably in all or most of all cats), with reactivation of FHV shedding following corticosteroid administration, parturition, lactation and other stressful situations.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Thomasy S M, Maggs D J (2016) A review of antiviral drugs and other compounds with activity against feline herpesvirus type 1. Vet Ophthamol 19 (Suppl 1), 119-130 PubMed.
  • Radford A D, Addie D, Belák S et al (2009) Feline calicivirus infection. ABCD guidelines on prevention and management. J Feline Med Surg 11 (7), 556-564 PubMed.
  • Thiry E, Addie D, Belák S et al (2009) Feline herpesvirus infection. ABCD guidelines on prevention and management. J Feline Med Surg 11 (7), 547-555 PubMed.
  • Addie D, Poulet H, Golder M C et al (2008) Ability of antibodies to two new caliciviral vaccine strains to neutralise feline calicivirus isolates from the UK. Vet Rec 163 (12), 355-357 PubMed.
  • Fontenelle J P, Powell C C, Veir J K et al (2008) Effect of topical ophthalmic application of cidofovir on experimentally induced primary ocular feline herpes-1 infection in cats. Am J Vet Res 69 (2), 289-293 PubMed.
  • Porter C J, Radford, A D, Gaskell R M et al (2008) Comparison of the ability of feline calicivirus (FCV) vaccines to neturalise a panel of current UK FCV isolates. J Feline Med Surg 10 (1), 32-40 PubMed.
  • Gutzwiller M E, Brachelente C, Taglinger K et al (2007) Feline herpes dermatitis treated with interferon omega. Vet Dermatol 18 (1), 50-54 PubMed.
  • Southerden P & Gorrel C (2007) Treatment of a case of refractory feline chronic gingivostomatitis with feline recombinant interferon omega. JSAP 48 (2), 104-106 PubMed.
  • Veir J K, Lappin M R, Foley J E et al (2002) Feline inflammatory polyps: historical, clinical, and PCR findings for feline calici virus and feline herpes virus-1 in 28 cases. J Feline Med Surg (4), 195-199 PubMed.


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