DISSEMINATED HALICEPHALOBUS-DELETRIX INFECTION IN A HORSE

A 13-year-old Quarter Horse gelding was referred for evaluation of a d raining tract and fracture of the right hemimandible of 4 weeks' durat ion. Two days prior to admission, the horse had developed pigmenturia. Radiography of the mandible revealed a fracture of the vertical ramus of the right hemimandible, loss of the right lower second premolar, a nd osteomyelitis involving an extensive portion of the hemimandible. U ltrasonography of the left kidney revealed loss of normal renal archit ecture. Histologic examination of tissue obtained from the right hemim andible revealed granulomatous osteomyelitis and multiple metazoan par asites identified as Halicephalobus deletrix. The horse was treated wi th antimicrobial and deworming agents, and the mandible was surgically debrided. The horse became atactic 8 days after surgery and was eutha natized. Necropsy identified parasitic migration in the right hemimand ible, kidneys, and CNS.