Abstract
A 10‐year‐old horse developed ataxia and incoordination and was submitted for necropsy after euthanasia. The main gross postmortem finding was of bilateral renal masses, and a renal carcinoma had been suspected. Also, nematodes were present in histological sections of the cervical spinal cord. The microscopic feature was marked granulomatous inflammation, in both kidneys and local lymph nodes, and the clinical and morphologic features of this case resemble those observed in other reports of
Halicephalobus gingivalis
infection in horses. Aspects of the pathogenesis and pathology are discussed. Infection with
H gingivalis
should be included in the differential diagnosis of horses with acute neurological disease. However, lesions of
H gingivalis
are likely to be present in other organs that may be clinically inapparent. Owing to the widespread geographic distribution of
H gingivalis
and its zoonotic potential, this parasite poses a risk to animal and human health.