Feline Chronic Gingivostomatitis (FCGS) is an inflammatory multifactorial disease of the oral cavity in cats, with an unclear etiology. It is highly painful, debilitating and difficult to treat for affected individuals and in severe cases even incompatible with life. The development of the disease is affected by a number of factors. Among the presumed predisposing factors are viral and bacterial infections, poor oral hygiene, breeding practices and stress. Feline Calicivirus (FCV) is present in majority of cats which have FCGS. Other viruses likely to be involved include Feline Herpesvirus (FHV1), Feline Immunodeficiency Virus (FIV) and Feline Leukaemia (FeLV). Given the common presence of multiple viral agents, determining their individual roles is challenging. Our study focused on the possibility of eliminating FCV in cats with FCGS.

In Vitro Study
An aqueous suspension of silver nano particles (20 nm) at a concentration of 5000 ppm was used for testing. Subsequent dilutions of 1:10 to 1:100 and 1:100 to 1:500 were made. 1/ Determination of Nano Ag Cytotoxicity on CRFK Cell Line (Crandell Rees Feline Kidney): 100µl of a suspension of the appropriate dilution was injected into five wells of a microtiter plate containing the feline kidney cell line. At dilutions of 1:10 to 1:100, a cytopathic effect was evident after 24 and 48 hours, respectively, in all cases. Dilution 1:200 partial cytopathic effect (3+/2-), dilution 1:300 (1+/4-). Dilution 1:400 without cytopathic effect. 2/ Determination of the Virocidal Effect of NanoAg on Feline Calicivirus: A field isolate of feline calicivirus was diluted with 2% DMEM solution at eight levels of virus dilution (10-1 - 10-8). Samples were exposed to NanoAg suspension at 1:400 dilution. NanoAg at this dilution exhibited FCV virocidal effect starting at 10-4 virus dilution. The calculated virus TCID50 value was 104,56.

In Vivo Study
Twenty-two cats aged 2 to 12 years with clinically manifested stomatitis were included in the study. There were 15 FCV unvaccinated and 7 FCV vaccinated cats in the study group. Breed and vaccine type were not considered. Clinical diagnosis was made and oropharyngeal and gingival sampling was performed. Subsequently, the patients were divided into control and test groups of 11 individuals each. The control group was left untreated. In the test group, silver nano particles contained in the mucoadhesive paste TraumaPet® oral gel Ag (NanoComplex Ltd.) were applied once a day. After 14 days, control sampling was performed in an identical manner. After collection, the samples were stored at - 80°C until the time of examination. The field strain FCV WSV Bio 84 (Bioveta, Ivanovice na Hané, Czech Republic) and the vaccine strain FCV F9 (Bioveta, Ivanovice na Hané, Czech Republic) were used as positive controls. After the series of samples were pooled, viral RNA was isolated and RT-PCR analysis of the samples was performed on a LightCycler® 480 II instrument (Roche Diagnostic).

Results
After 14 days of nanoag aplication,, all of the 11 cats in the test group were FCV negative. In the control group, spontaneous disappearance of the virus occurred in 6 of the 11 cats tested and 5 cats continued to shed the virus. The results were subjected to statistical analysis by Fisher’s test. The difference between the treatment and control groups was statistically significant (P = 0.0351). Application of NanoAg has a statistically significant effect on the inhibition of feline calicivirus in the oral mucosa of cats.