Over a one year period (November 2000-December 2001), clinical specimens from 189 dogs and 38 cats, from the city of Fortaleza, Ceará, Brazil, were examined at the Specialized Medical Mycology Center at the Federal University of Ceará to detect animals with dermatophytoses. The mycological analyses were conducted by direct microscopy and by fungal culture on Sabouraud agar, Sabouraud chloramphenicol agar and Mycosel agar. Dermatophytes were isolated from 27 of the 189 (14.3%) canine specimens and 14 of the 38 (36.8%) feline specimens. The identified dermatophytes were Microsporum canis (95%), M. gypseum (2.5%) and Trichophyton mentagrophytes var. mentagrophytes (2.5%). Microsporum canis was the most common species isolated (92.6% and 100%, for dogs and cats respectively). The percentage of positive direct microscopic examinations of clinical specimens and positive cultures was 61%. There was a high proportion of positive cultures from cats less than 1 year of age, but in dogs no significant differences were detected. There were no significant differences between the sexes. Dermatophytes were more frequently isolated in March, April and May, but no significant differences were detected in the seasonal distribution of canine and feline dermatophytoses.

The main objective of this investigation was to evaluate different methods of storage for Microsporum canis based on materials and equipment that are readily available in developing countries. We tested 32 strains of M. canis at - 20 degrees C in potato dextrose agar (PDA) in its plain condition, or amended with 10% dimethyl sulfoxide or with 10% glycerol. In addition, we tested 25 degrees C storage of isolates in plain saline (0.9% NaCl) and in saline covered with a mineral-oil layer. After 9 months of storage, none of the M. canis strains frozen in PDA supplemented with glycerol survived, while only 16 and 6%, respectively, of the isolates in plain and DMSO medium lost viability. Nine month's storage in saline with or without mineral oil increased the amount of pleomorphic development of sterile hyphae; this phenomenon occurred at a significantly higher level than was seen in isolates stored at -20 degrees C. The physiological characteristics of M. canis were not affected by the different storage tests. The results suggest that, in order to ensure optimal viability, purity and pristine isolate condition, each M. canis isolate maintained should be held in at least two methods of storage, namely, PDA at -20 degrees C and saline with a mineral-oil layer at 25 degrees C.