Feline Calicivirus - Treatment and Prevention

Treatment and Prevention

There is no specific treatment for FCV. Antibiotics are used for secondary bacterial infections, and immune modulators, such as lymphocyte T-cell immune modulator, have been used for immune support. Nursing care and rehydration are used for dehydrated and anorexic cats. Corticosteroids or azathioprine may be used for polyarthritis. Stomatitis is very difficult to treat. Antibiotics, corticosteroids, and tooth extractions all have been used with varying success. Cats on corticosteroids must be monitored carefully for worsening of any upper respiratory infection.

Natural immunity from maternal antibodies lasts in the kitten from three to nine weeks. After that, kittens are susceptible to FCV. Previous infection does not guarantee lifelong immunity, since an antigenically dissimilar FCV (such as VS-FCV) can cause infection. However, usually after the age of three years, FCV infections are mild or asymptomatic. FCV vaccination will not always prevent disease, but will reduce or weaken the severity. FCV vaccines come in two types, inactivated (ATCvet code: QI06AA07) and attenuated (live, but not virulent; in various combination vaccines). They have been shown to be effective for at least three years. Attenuated FCV vaccine has been shown to possibly cause mild upper respiratory infection. Inactivated vaccine does not, but it causes more local inflammation and possibly predisposes the cat to vaccine-associated sarcoma. The only vaccine licensed for prevention of VS-FCV is CaliciVax, manufactured by Fort Dodge Animal Health, a division of Wyeth. It also contains a strain of the traditional FCV virus. Since VS-FCV has arisen from variant strains of FCV, it is not certain that a vaccine for one virulent strain will protect against all virulent strains.

Quarantine is best for control of FCV in catteries and kennels. However, FCV is very contagious, and latently infected cats will continue to shed viruses, so complete control is difficult. An outbreak of VS-FCV at a humane society in Missouri in 2007 led to the euthanasia of the entire cat population (almost 200 cats) to contain it. FCV may survive several days to weeks in a dry environment and longer in a cooler, wet environment. Quaternary ammonium compounds are not thought to be completely effective, but a 1:32 dilution of household bleach used with a detergent and sufficient contact time does seem to kill the virus.