feline conjunctivitis

• Usually primary infectious cause: history and clinical signs may help direct treatment (e.g. corneal involvement -> suspect FHV-1)

  • Topical chloramphenicol or tetracycline good first line choices
  • Treat concurrent respiratory signs as appropriate
• If recurrent, consider swab for PCR to inform diagnosis/treatment

  • Chlamydophila infections need systemic antibiotics
  • FHV-1 infection may need anti-virals
• Chlamydophila felis is an obligate intracellular bacterium which is a common cause of feline conjunctivitis. Clinical signs includes…

  • Unilateral conjunctivitis, becomes bilateral within a few days
  • Chemosis often marked, hyperaemia
  • No corneal signs
  • Absent or mild upper respiratory disease
  • Diagnosis involves clinical signs +/- conjunctival swab for PCR test
  • Systemic treatment indicated as organism affects respiratory tract, GIT and reproductive tract as well as eye. Doxycycline is the antibiotic of choice
• Feline herpesvirus-1 (FHV-1) is an important ocular pathogen that has clinical signs which vary according to age…

  • Kittens and young cats have bilateral conjunctivitis in conjunction with upper respiratory signs (cat flu) +/- corneal ulceration
  • Adult cats have unilateral ocular discharge with mild conjunctivitis and a history of previous upper respiratory infection.
  • Wide range of other conditions, e.g. corneal ulceration, sequestrum, entropion, eosinophilic keratitis
• Diagnosis for herpes virus involves history clinical signs and a conjunctival swab for PCR test. Care with interpretation:

  • False negatives common d/t intermittent shedding
  • False positives are common as many cats have been exposed to FHV-1, so positive result could reflect FHV-1 reactivation that is coincidental or secondary to the ocular disease.
• Treatment of herpes virus involves…

  • Nursing which consists of cleaning eyes, nutrition and rehydration
  • Broad-spectrum antibiotic to prevent/treat secondary bacterial infection
  • Topical for eyes (e.g. fusidic acid, chloramphenicol)
  • Systemic for respiratory involvement e.g. amoxycillin-clavulanate
  • Anti-virals
  • Topical e.g. ganciclovir 4x daily
  • Systemic e.g. famcyclovir (expensive) 90mg/kg BID recommended dose
• Feline calicivirus (FCV) involves upper respiratory disease, oral ulceration, polyarthritis and conjunctivitis

  • Anti-viral treatment is ineffective