Peripheral vestibular disease caused by Raillietia auris in a Barzona bull in the USA

摘要

A 2.5-year-old Barzona bull presented for right-sided head tilt and decreased libido of 3-week duration. Video otoscopy of the external ear canal revealed severe erythema, stenosis, purulent debris, necrosis and numerous live Raillietia auris mites. Decontamination via saline lavages, injectable ceftiofur and dexamethasone treatments failed. Topical 10% permethrin solution in mineral oil proved efficacious at killing R. auris mites, and injectable tulathromycin and dexamethasone were administered until resolution of the bacterial otitis; however, the head tilt persisted, and the bull was slaughtered. Systemic administration of ceftiofur was not effective as a sole treatment, and topical antimicrobial treatments were significantly limited per Food Animal Residue Avoidance Databank regulations. Video otoscopy was a useful tool in the rapid diagnosis and management of the otitis. This case highlights the long-lasting impact of otitis secondary to R. auris mite infestation and the importance of ectoparasite control and rapid treatment of otitis in bovids.