A 7-year-old male bongo (Tragelaphus eurycerus) presented to the Veterinary Teaching Hospital (VMTH) at the University of Florida, with a 3-month history of left ear droop, intermittent ataxia, and inappetence. At the VMTH, the animal was observed fully conscious, paying particular attention to the nervous system. The animal had a marked head tilt to the left, decreased menace response on the left, reduced moisture on the left side of the nose, and a decreased spontaneous blink response on the left. The left ear did not move. The animal circled to the left, its tongue occasionally hung from the left side of the mouth, and he wobbled occasionally when walking.
The animal was anesthetized and a radiographic bulla series was completed. Complete filling of the left osseous bulla with soft tissue opacity was visualized on the radiographs. The exact osseous margins of the bulla were indistinct consistent with a periosteal reaction.
Two days following the anesthesia for radiographs, the animal was anesthetized for a left lateral bulla osteotomy. Culture and sensitivity of the lining of the left bulla yielded a heavy growth of Arcanobacterium pyogenes (previously Actinomyces pyogenes) that was sensitive to oxytetracycline on Kirby-Bauer susceptibility. The bongo was treated with a 30-day course of oxytetracycline (LA-200 20 mg/kg IM q48h). The animal showed gradual improvement, and within 2 months of surgery all vestibular signs had resolved. The only persistent clinical sign was a slight droop of the left ear.