Overview and Prevalence
Feline viral rhinotracheitis (FVR) is a highly contagious upper respiratory infection caused by feline herpesvirus-1 (FHV-1). It is one of the most common respiratory diseases in cats worldwide, affecting cats of all ages but particularly kittens, shelter cats, and immunocompromised individuals. FVR is a major component of the feline upper respiratory infection complex, accounting for up to 50% of cases.
Early Warning Signs and Symptoms
Symptoms typically appear 2–6 days after exposure. Early signs include:
- Sneezing and nasal discharge (clear to purulent)
- Conjunctivitis and ocular discharge
- Lethargy and decreased appetite
- Fever (up to 104°F/40°C)
- Drooling or hypersalivation
- Ulcerative keratitis (corneal ulcers) in severe cases
Chronic carriers may show recurrent mild signs during stress.
Common Causes and Risk Factors
FVR is caused by FHV-1, a DNA virus that spreads through direct contact with infected cats, contaminated objects (fomites), or aerosolized droplets. Risk factors include:
- Multi-cat households, shelters, or catteries
- Young age (<6 months) or old age
- Stress (boarding, surgery, new pet)
- Poor ventilation and overcrowding
- Unvaccinated status
Prevention Measures
Vaccination
The FVRCP or FVRCPC (feline viral rhinotracheitis, calicivirus, panleukopenia) vaccine is core. Kittens receive 3 doses starting at 6–8 weeks, then boosters annually or every 3 years. Vaccination reduces severity but not infection.
Hygiene Management
Clean and disinfect food bowls, litter boxes, and surfaces with bleach solutions (1:32 dilution). Wash hands between handling cats.
Environmental Control
Provide good ventilation, reduce stress, and avoid overcrowding. Use air purifiers if needed.
Nutrition and Immune Support
Feed high-quality diet, consider lysine supplements (250–500 mg/day) (though controversial), and ensure regular veterinary check-ups.
Diagnostic Process
Veterinarians diagnose FVR based on history and physical exam. Tests include:
- PCR testing (on conjunctival or nasal swabs) – most sensitive
- Viral culture or immunofluorescence
- Blood work (CBC, serology)
- Schirmer tear test and fluorescein stain for corneal ulcers
Treatment Options: Home Care and Veterinary Therapy
Home Care
- Warm, humid environment (nebulization with saline for 15 min)
- Encourage eating with strong-smelling food (e.g., tuna, chicken)
- Clean nasal and ocular discharge with warm damp cloth
- Offer fluids; consider subcutaneous fluids if dehydrated
Veterinary Treatment
- Antiviral drugs: famciclovir (40–90 mg/kg orally twice daily), topical idoxuridine or cidofovir for eyes
- Antibiotics for secondary bacteria (doxycycline, amoxicillin-clavulanate)
- Ocular lubricants or antibiotics for corneal ulcers
- Nebulization with saline or antibiotics (e.g., gentamicin)
- Hospitalization for severe cases: IV fluids, nutritional support
When to Seek Emergency Care
Immediate veterinary attention is needed if your cat:
- Has difficulty breathing (open-mouth breathing, blue gums)
- Refuses to eat or drink for >24 hours
- Shows severe lethargy or collapse
- Has corneal ulcers (squinting, cloudiness)
- Develops pneumonia symptoms (coughing, fever)
Prognosis, Recovery, and Long-Term Management
Most cats recover within 10–14 days with supportive care. However, up to 80% become latent carriers, shedding virus sporadically during stress. Corneal ulcers may take weeks to heal. Long-term management includes:
- Minimizing stress (routine, pheromone diffusers like Feliway)
- Yearly vaccinations
- Supplementing L-lysine (though efficacy debated)
- Monitoring for recurrent flare-ups
- Keeping indoor only to reduce exposure
With proper care, cats can live normal lives. Severe cases in kittens or immunocompromised cats may have guarded prognosis.