Overview and Prevalence
Feline calicivirus (FCV) is one of the most common viral pathogens in cats, responsible for up to 40% of feline upper respiratory infections (URIs). It is highly contagious and spreads through direct contact, sneezed droplets, and contaminated surfaces. FCV is particularly prevalent in multi-cat households, shelters, and catteries. The virus can survive on surfaces for several days, making environmental control challenging.
Early Warning Signs and Symptoms
Clinical signs typically appear 2–6 days after exposure. Common symptoms include:
- Sneezing and nasal discharge
- Conjunctivitis and ocular discharge
- Oral ulcers (especially on the tongue, gums, and hard palate)
- Drooling and salivation
- Fever
- Lethargy and depression
- Loss of appetite or anorexia
Some strains cause more severe symptoms like pneumonia, limping syndrome (lameness), or virulent systemic disease (VSD) with high mortality.
Common Causes and Risk Factors
FCV is caused by a small, non-enveloped RNA virus. Risk factors include:
- Multi-cat environments (shelters, breeding catteries, boarding facilities)
- Unvaccinated or incompletely vaccinated cats
- Young kittens (immune system not fully developed)
- Stress (crowding, poor nutrition, concurrent illness)
- Immunosuppression (FIV, FeLV infection, drug therapy)
Prevention Measures
Vaccination
Annual vaccination is the cornerstone of prevention. Core vaccines include a combination of FCV, feline herpesvirus (FHV-1), and feline panleukopenia. Vaccination reduces severity but may not prevent infection entirely.
Hygiene and Isolation
- Isolate infected cats for at least 2 weeks after symptoms resolve.
- Disinfect food bowls, litter boxes, and surfaces using bleach (1:32 dilution) or accelerated hydrogen peroxide.
- Hand hygiene: Wash hands after handling different cats.
Diet and Stress Reduction
- Provide a balanced diet to boost immunity.
- Minimize stress by maintaining routine and avoiding overcrowding.
Regular Veterinary Check-ups
Annual exams help monitor health and update vaccines.
Diagnostic Process
Veterinarians may perform:
- Physical examination to assess fever, oral ulcers, respiratory signs.
- PCR (polymerase chain reaction) on swabs from the mouth, nose, or eyes to detect viral RNA.
- Virus isolation (less common due to time).
- Blood tests to rule out other diseases and assess overall health.
Treatment Options: Home Care and Veterinary Treatment
Supportive Home Care
- Encourage eating: Offer strong-smelling, soft foods (e.g., tuna, pâté) to stimulate appetite; warm food slightly.
- Hydration: Provide fresh water; use subcutaneous fluids if dehydrated (veterinary guidance).
- Oral care: Apply prescribed oral gels to soothe ulcers; avoid dental brushing until healed.
- Clean eyes and nose: Use saline-soaked cotton balls to remove discharge.
- Humidifier: Helps ease congestion.
Veterinary Treatment
- Antibiotics: Prevent secondary bacterial infections (e.g., doxycycline, amoxicillin-clavulanate).
- Antiviral drugs: In severe cases, veterinarians may use feline interferon omega (FelFN) or other immunomodulators. No specific antiviral is licensed for FCV.
- Pain management: NSAIDs (e.g., meloxicam) or oral pain relievers for mouth ulcers.
- Fluid therapy: Intravenous or subcutaneous fluids for dehydration.
- Nasal decongestants: Only if prescribed by a vet.
Common Medications or Therapies
| Medication | Use | Route |
|---|---|---|
| Doxycycline | Antibiotic for secondary infections | Oral |
| FelFN (interferon omega) | Antiviral/immunomodulator | Ophthalmic or oral |
| Meloxicam | Pain relief | Oral |
| L-lysine | May reduce replication (controversial) | Oral |
When to Seek Emergency Care
Immediate veterinary attention is needed if:
- Difficulty breathing (open-mouth breathing, blue gums).
- Complete refusal to eat or drink for more than 24 hours.
- Severe lethargy (unable to stand).
- High fever (over 104°F / 40°C).
- Bloody discharge from nose or mouth.
- Signs of systemic disease (jaundice, widespread bruising, sudden death).
Prognosis, Recovery, and Long-term Management
Most cats recover within 2–3 weeks with supportive care. Mortality is low except in virulent systemic strains (up to 40% mortality). Recovery involves:
- Isolation until symptom-free.
- Gradual return to normal diet.
- Monitor for chronic stomatitis (persistent oral inflammation) in some cats.
Long-term, vaccinated cats can still be carriers. Stress management and hygiene are crucial to prevent flares. Cats with chronic stomatitis may require dental cleaning or extractions.