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. Herbal extracts as a source of compounds with an antiviral activity has attracted significant attention recently. Two researches independently published in 2016 screened a library of natural chemicals against FCV. The first one showed that Theaflavin and its derivatives but not Kaempferol significantly inhibited entry of FCV into cells. On the contrary, authors of the second article claimed that kaempherol showed anti-FCV activity, but theaflavin treatment was insufficient. This striking difference may be (at least partially) explained by differences in testing conditions. Indeed, further studies of activity, as well as molecular mechanisms of action, needed. Use in research Because of the similarity of FCV to norovirus, a common cause of gastroenteritis in humans, FCV has been used as a surrogate for it in research. For instance, studies have been done on the survival of FCV in foodstuffs, the effectiveness of handwashing on FCV removal, and the use of ozone gas to inactivate FCV found in hotel rooms, cruise ship cabins, and healthcare facilities. It is also used in general Caliciviridae research due to its being one of the few of that group of viruses that grows well in vitro. See also