Otitis externa in free-roaming cat population: Clinical examination, cytology, and mycology culture.

BACKGROUND

Free-roaming cats are a potential source of several infectious and parasitic diseases that can be easily transmitted to outdoor pet cats.

AIM: The purpose of this study was to determine the prevalence and pattern of co-occurrence of causative agents of otitis externa and to identify associated risk factors in free-roaming cats living in the continental region of Croatia. In addition, we investigated the presence of Malassezia yeasts in the external ear canals of cats using mycology culture.

METHODS

Clinical assessment of otitis externa involved auricular and otoscopic examinations. Samples of cerumen and ear swabs were collected and analyzed via cytological examination and mycological culture.

RESULTS

The frequency of otitis externa in the population of free-roaming cats was 40.5% (30/74) based on the presence of Otodectes cynotis, Malassezia yeasts, cocci, rods, and/or neutrophils. Results revealed multiple diagnoses for the same ears and unevenly affected ears of the same cats. O. cynotis was detected in 25.7% (19/74) of the cats and was the primary cause of otitis in 63.3% (19/30) infected cats. Co-diagnosis of O. cynotis and Malassezia yeasts was common at both the ear (39.3%, 22/56 infected ears) and cat (40.0%, 12/30 infected cats) levels, while Malassezia was causing otitis in 30% (9/30) infected cats. Three or more diagnoses co-occurred in 15% of infected ears and 27% of infected cats. The clinical signs of otitis externa were absent in 8.9% (5/56) of infected ears, all affected by Malassezia alone or with O. cynotis. Malassezia yeasts were cultured in 83.3% (25/30) of the otitis cases, with heavy growth in 70% and Malassezia pachydermatis as the predominant species in all cases.

CONCLUSION

The high prevalence of otitis externa caused by O. cynotis and Malassezia yeasts in free-roaming cats in Croatia provides important insights into the health status of this cat population. Although otitis externa and its causative agents are frequently found in free-roaming cats, the actual prevalence of otitis externa and all associated risk factors have not been thoroughly assessed.