Noculation with IDV or CLIDV did not provide prophylactic immunity against topical challenge exposure with M canis. Inoculation with either vaccine did not provide a more rapid cure of an established infection.

Results suggested that oral or SC administration of lufenuron to cats, at the dosages used and under the conditions of this study, did not prevent establishment of dermatophytosis following exposure to infected cats. Infection was established more slowly among cats treated with lufenuron, but once established, infection resolved in approximately the same amount of time in lufenuron-treated as in control cats.

Oral lufenuron is reportedly an effective treatment for some cats with dermatophytosis. The purpose of this study was to determine if lufenuron, when used as a pre-treatment prior to challenge exposure, would be protective against the development of infection after the direct topical application of fungal macrocondia (Microsporum canis spores). Three groups (n = 6/group) of juvenile cats were treated with either monthly oral lufenuron (30 or 133 mg/kg) or placebo. After 2 months of treatment, kittens were challenged using 10(5)Microsporum canis spores applied to the skin under occlusion. Cats were examined weekly and the following data collected: Wood's lamp examination; scoring for scale/crust, erythema and induration; lesion size; and the development of satellite lesions. Fungal cultures were performed bi-weekly. All cats became infected; the infections progressed, and then regressed, in a similar fashion in all groups. There were no consistent statistically significant differences in weekly infection scores between treated and untreated cats throughout the study. Treated cats did not recover faster than untreated cats. We conclude that oral lufenuron at the dosing schedule and conditions used in this study did not prevent dermatophytosis or alter the course of infection by direct topical challenge.

Oral lufenuron is reportedly an effective treatment for some cats with existing dermatophytosis. We sought to determine if lufenuron, when used as a pre‐treatment prior to challenge exposure and infection, would prospectively protect against development of infection by direct application of Microsporum canis spores. Three groups (n = 6 per group) of juvenile cats were treated with either monthly oral lufenuron (30 or 133 mg kg−1) or placebo. After 2 months of treatment, kittens were challenged using 105Microsporum canis spores applied to the skin under occlusion. Cats were observed weekly, including: Wood’s lamp examination; scoring for scale/crust, erythema, induration; lesion size; and development of satellite lesions. Fungal cultures were performed biweekly. All cats became infected; the infections progressed, and then regressed, in a similar fashion in all groups. There were no consistent statistically significant differences in weekly infection scores throughout the study. Treated cats did not recover faster than untreated cats. We concluded that oral lufenuron at the dosing schedule and conditions used in this study did not prevent dermatophyte infection by direct topical challenge. Further studies are warranted to evaluate alternate dosing schedules, less severe challenge exposures, varying strains of M. canis, and other factors that may be present under field conditions.  This study was funded by Novartis Animal Health.