Pretreatment with feline interferon omega and the course of subsequent infection with feline herpesvirus in cats

Objective:Recombinant feline interferon omega (rFeIFN-ω), a type I IFN, may have the potential to limit virus replication and associated clinical signs when administered early on in the course of feline herpesvirus type 1 (FHV-1) infection and reactivation, respectively. The effect of rFeIFN-ω pretreatment on the course of subsequent FHV-1 infection in cats was investigated. Animals studied: Nine SPF cats were divided into an IFN group (n=5) and a control-group (n=4). Procedures: The IFN group was pretreated for 2 days with 10 000 units rFeIFN-ω twice aday topically into both eyes and 20 000 units rFeIFN-ω once a day orally, whereas the control group was mock-treated. Subsequently all cats were infected with FHV-1. Samples for FHV-1 DNA detection and quantitation, virus isolation, and titration of FHV-1 antibodies were collected. Clinical and ocular signs were recorded and scored. Results: Courses of median individual clinical and ocular scores and virus load did not differ significantly between both groups using for repeated measurements. Analysis (Anova)of each individual ocular parameter revealed significantly high scores for epithelial keratitis (P=0.016) in the IFN group compared to the control group. Periods of virus shedding did not differ significantly between both groups using the Wilcoxon rank sum test. Conclusions: Results indicated a lack of beneficial effects of rFeIFN-ω pretreatment in the course of primary FHV-1 infection in cats