An Update on Feline Calicivirus.

INTRODUCTION Feline Calicivirus (FCV) is one of the most common viral pathogens in domestic cats worldwide. The first report of FCV dates back to 1957, when FCV was isolated from the gastrointestinal tract of cats in New Zealand. Subsequent reports recognised FCV as a cause of respiratory disease in cats, and at present, feline practitioners worldwide are daily confronted with cats suffering from suspected FCV. The highly mutagenic nature of FCV and its high genetic plasticity enable the virus to successfully survive in the feline population, and pose a special challenge as regards the diagnosis, treatment, and prevention of FCV-induced disease. Upper respiratory tract disease has been considered a common clinical sign of FCV infection. A study from Switzerland demonstrated that oral ulcerations, salivation and gingivitis-stomatitis were more commonly associated with FCV infection than upper respiratory tract disease, and less than half of the cats suspected to have FCV infection were found to be FCV-positive. Furthermore, a study investigating FCV isolates from Switzerland found some evidence that the genetic background of cats might influence their susceptibility to FCV infection. This review article provides a comprehensive summary of the FCV literature, and integrates the results of recent research on FCV's genetic characteristics, the cellular and humoral immunity evoked by FCV vaccination and infection, the diagnosis of FCV, FCV prevention/vaccination, the risk factors associated with FCV, and the hygienic measures necessary in FCV-contaminated areas. After each section, the key points are summarised, and relevant information is outlined to help feline practitioners in FCV diagnosis, treatment and prevention.