Maxillary Granulomatous Inflammation Caused by Halicephalobus gingivalis (Nematoda) in a Connemara Mare in Belgium

A 5-year-old anorexic and lethargic Connemara mare presented with severe facial swelling and dyspnea. No distinct central nervous symptoms were present. Radiographs of the skull showed diffuse radiolucency with loss of definition of the periodontal lamina dura and swelling of the decalcified nasal bones. Given the severe bone damage and its poor general condition, the pony was euthanized. Histological evaluation of the lesion revealed a granulomatous reaction with numerous sections of adult and juvenile nematodes, which were morphologically and molecularly identified as Halicephalobus gingivalis. The position of this facultative parasite within its free-living congeners is reviewed in this article, and the possible infection routes are discussed. This report presents the first record of equine halicephalobiasis in Belgium.