Successful diagnosis and treatment of Orthohalarachne attenuata nasal mites utilising voluntary rhinoscopy in three Pacific walrus ( Odobenus rosmarus divergens )

A 17‐year‐old adult female walrus presented with copious nasal discharge for one week duration despite a normal appetite and attitude. Antibiotic treatment was initiated based on culture results from the nasal discharge. The amount of nasal discharge decreased dramatically during antibiotic treatment but returned soon after the treatment ended. The walrus had a mild leucocytosis, normal thoracic ultrasound and normal skull radiographs. After four weeks of training, voluntary endoscopy of the anterior nasal cavity was performed revealing mucus surrounding nasal mites, which were collected. The nasal mites were examined microscopically and determined to be Orthohalarachne attenuata nasal mites. The patient was successfully treated with ivermectin 0.2 mg/kg by mouth two weeks apart. This report highlights the importance of medical husbandry training to perform diagnostic procedures without the risk of anaesthesia.