Otoscopy and aural cytological findings in a population of rescue cats and cases in a referral small animal hospital in England and Wales.

Objectives: Otitis externa is seen clinically in cats, although studies investigating this condition within the UK are lacking. The objective of this study was to investigate the prevalence of mites and microbial infection in the ear canals of cats in various rescue centres and a referral hospital.

Methods: Otoscopy was performed in 332 cats. Otoscopic findings were noted, including the gross visualisation of species. A sample of cerumen was collected for cytological evaluation and a cerumen smear for detection of mites if there was a large amount of aural exudate present.

Results: infestation was noted in 3/341 cats (0.9%, 95% confidence interval [CI] 0.3-2.6). A total of 129/341 (37.8%; 95% CI 32.7-43.0) cats were found to have species within one or both ears. Bacteria were found unilaterally in 9/341 (2.6%; 95% CI 1.4-4.9) cats. Analysis of the cytological findings showed an increased likelihood for species to be present as age increased (n = 293; Pearson = 0.204, <0.001). There was also an increased likelihood of finding species in both ears if found within one ear (n = 327; = 0.499, <0.001). There was a positive correlation between the number of organisms and the quantity of aural exudate (n = 338; = 0.778, <0.001). Cats in which species infestation were noted (n = 3) had moderate or large quantities of cerumen.

Conclusions And Relevance: This study shows that there was a low prevalence of in this cohort of cats. In normal cats it was not unusual to find microorganisms upon aural cytology, bacteria were noted far less frequently and in two cats this was associated with underlying anatomical pathology.