 |
This article is still under construction. |
|
Pathogenesis
- Upper respiratory tract infection: Feline Viral Rhinotracheitis
- Viruses and bacteria are involved in the complex
- The most frequent aetiologic agent is FHV-1, and less frequently feline calicivirus and/or Chlamydophia psittaci
- All three agents infect URT respiratory epithelium, although FHV-1 has the highest affinity for this epithelium
- Feline calicivirus more frequently infects the oral mucosa -> ulcerative stomatitis
- C.psittaci more frequently infects the conjunctival epithelium -> chronic conjunctivitis
- Infection of the respiratory epithelium by FHV-1 results in a typical neutrophilic rhinitis with intraepitheial intranuclear eosinophilic inclusion bodies, with expected clinical signs
- Resolution of clinical signs usually occurs by 7-14 days
- FHV-1 remains latent in the trigeminal ganglion, and can reactivate at times of stress: Can infect the cornea -> ulcerative keratitis
- Occasional mortality in kitten or immunocompromised animals usually associated with secondary bacterial infection
- Erosions can affect the bronchi, resulting in interstitial pneumonia
- Most common cause of keratitis and corneal ulcers in cat and gummy eyes in kittens
- Rupture is a particular risk
Epidemiology
- Widespread
- Serious infection
- Latent infection can be reactivated on boarding
Diagnosis
- Nasal swabs on first week of infection can be cultured for virus isolation
Treatment
For keratitis with corneal ulcers:
- Subcut omega interferon
- Topical trifluorothymidine (thymidine analogue) on eyes
Control
- Killed and live vaccines are available
- Live vaccines have provoked symptoms in immunosuppressed kittens and are no longer used in the UK