Prevalence and characterization of Microsporum canis carriage in cats

In order to determine the prevalence and to characterize the carriage of Microsporum canis in cats, different mycological examinations (including a culture obtained by hair brushing and Wood's light examination) were performed on 632 animals of different origins. Group 1 comprised 467 healthy pet cats belonging to veterinary students. In this group, prevalence of carriage was 2.1%: eight cats were asymptomatic transient carriers and one cat was an asymptomatic infected animal presenting discrete Wood's-positive lesions disseminated on the whole body that were visible after sedation and clipping. The carriage prevalence was higher (15.7%) in group 2 comprising 134 European cats destroyed in a pound and kept together. In two additional groups of cats, it was shown that an infected cat was responsible for the dissemination of fungal material into its environment including the other in-contact animals. When the active source of fungus was removed, the dissemination stopped, resulting in a decrease in the amount of infective material recovered from both the animal carriers and the environmental surfaces. This was also observed in two experimental groups of guinea pigs. No association between feline immunodeficiency virus infection and the M. canis carriage was observed in a retrospective case-control study performed on group 2. None of these cats was feline leukaemia virus positive.