An Introduction to Feline Calicivirus

Feline calicivirus affects your cat's mouth, sinuses, nasal passages and the feline upper respiratory tract. Feline calicivirus causes a range of symptoms including nasal and eye discharge, fever, loss of appetite, lesions in the mouth and corneal ulcers. Here's what you should know about feline calicivirus, its symptoms and treatment.

Feline Calicivirus and Its Symptoms

Feline calicivirus is spread through contact with nasal and eye discharge from an infected cat, usually through cat to cat contact. However, the virus can also be spread through contact with contaminated food dishes, hands and bedding.

It has an incubation period of 1 to 14 days. The illness itself lasts between one and two weeks. Symptoms include:

  • Nasal discharge, sometimes but not normally accompanied by sneezing
  • Eye discharge
  • Oral ulcers and chronic gingivitis
  • Pneumonia
  • Joint and muscle pain, ulcers on the paws
  • Inconsistent fever
  • Mild loss of appetite
  • Mild depression

Feline calicivirus can survive outside the host for eight to ten days. You'll need a 1:32 solution of bleach and water to kill the virus on household surfaces. Your cat may continue to carry the virus for years.

Diagnosis and Treatment

Diagnosis is based on medical history, clinical signs, and laboratory tests. If your cat has recurrent episodes of the disease, suffers from symptoms for longer than two weeks, or gets sick even though he's been vaccinated, he may be suffering from feline leukemia virus or feline immunodeficiency virus, both of which display similar symptoms.

Treatment involves keeping the eyes and nasal passages clear. Your vet may recommend increasing humidity with a vaporizer and using a prescription nasal decongestant.

Cats with severe nasal congestion may need to be force fed. This is because cats won't eat when they can't smell their food.

Your cat should be kept quiet and warm. Oral antibiotics may be needed to treat any secondary infections. Antibiotic eye ointments may be needed to treat corneal ulcers.

Cats with feline calicivirus are usually not hospitalized unless their symptoms are quite severe. In the most severe cases, fluid therapy, supplemental oxygen and a feeding tube may be needed.

Prevention and Control of Feline Calicivirus

The best way to prevent feline calicivirus infection is through vaccination. Several types of vaccines are available, including a modified live injectable vaccine, a modified live intranasal vaccine and a killed injectable vaccine.

The modified live injectable vaccine is usually a combination vaccine that also protects against rhinotracheitis, calicivirus and panleukopenia. This vaccine is best administered to cats older than twelve weeks of age.

For very young kittens and cats in need of more immediate protection, the intranasal vaccine is preferable. It provides antibody protection within two to four days of being administered. Mild sneezing and nasal discharge often occur as a side effect of this vaccine, but these aren't serious. This vaccine is ideal for cats who are at high risk of unavoidable exposure to feline calicivirus.

The killed injectable vaccine is safe for use in pregnant cats and usually comes as a combination vaccine. They can also be used in immunodeficient cats and in very young kittens.