Case history: A 1-year-old Border Terrier presented with acute onset of neurological signs and neck pain.
Clinical findings: Severe generalised ataxia, muscle tremors and cranial nerve deficits were noted. Multifocal brain lesions were suspected based on neurological examination. Computed tomography revealed an abdominal mass and cerebellar herniation through the foramen magnum.
Laboratory and pathological findings: Cytological and histopathological analysis of the abdominal mass revealed necrotising and granulomatous lymphadenitis with intralesional algal elements most consistent with Prototheca spp.. Culture of a sample from the mesenteric lymph node confirmed the presence of Prototheca spp. which was identified as P. bovis based on sequencing of a DNA fragment amplified by PCR. Following inadequate response to symptomatic therapy and poor prognosis, the dog was subjected to euthanasia. Histopathological evaluation of the central nervous system lesions, identified granulomatous meningitis and ventriculitis with the presence of intralesional algae.
Diagnosis: Disseminated protothecosis with granulomatous meningitis and ventriculitis caused by Prototheca bovis (formerly P. zopfii gen. 2).
Clinical relevance: This is the first case report of disseminated protothecosis with central nervous system involvement in a dog in New Zealand.
Keywords: Prototheca; canine; disseminated; lymphadentitis; neurological; protothecosis.