Prevalence of yeasts and mycelial fungi in bovine parasitic otitis in the State of Minas Gerais, Brazil.

Infestations by rhabditiform nematodes and acarids of the genus Raillietia are considered the primary causes of external otitis in cattle in tropical regions. Recently, yeasts of the genus Malassezia have been associated with a relatively high percentage of otitis cases, but the occurrence of other yeasts and mycelial fungi has not yet been reported in the literature. This work studied the presence of fungi in the ear canal of 45 cattle with external parasitic otitis. The results were positive for yeasts of the genus Malassezia in 31 (68.9%) of the 45 cultures in Mycosel medium supplemented with olive oil. The 45 cultures in Sabouraud dextrose medium revealed the growth of seven (15.5%) yeasts of the genus Candida, five (11.1%) Rhodotorula mucilaginosa, two (4.4%) fungi of the genus Aspergillus and eight 'Micelia sterilia'. Future studies may confirm and elucidate the importance of these agents in the aetiology of bovine otitis.