A systematic review of clinical and diagnostic investigation findings, therapy and outcomes of canine cases diagnosed with Neospora caninum and undergoing magnetic resonance imaging

Neringa Alisauskaite^*

• Northwest Veterinary Specialists part of Linnaeus Group, Runcorn, United Kingdom

Background: While MRI is increasingly used in the diagnostic workup of canine CNS disorders, its role in neosporosis has not been systematically characterized. Numerous questions remain regarding optimal diagnostic approaches and treatment protocols, and large-scale studies are lacking. Objectives: To systematically review and analyze published cases of canine neosporosis undergoing MRI examination of CNS and identify clinical, diagnostic, and treatment variables associated with outcomes. Methods: A comprehensive literature search was performed using PubMed and Google Scholar. Inclusion criteria were confirmation of N. caninum infection by serology, PCR, or histopathology, and MRI performed at diagnosis. Extracted data included signalment, clinical signs, MRI features, CSF results, serology, PCR, treatment, and outcomes. Statistical analyses assessed associations and correlations among diagnostic and outcome variables. Results: Eighty-two cases extracted from 11 publications met inclusion criteria. MRI commonly revealed multifocal intra-axial lesions, with cerebellum commonly affected, with variable contrast enhancement of brain, meninges, and consistent contrast enhancement in the muscles. A significant association was identified between elevated CSF TNCC and positive CSF PCR. Treatment duration strongly correlated with survival. Death/euthanasia due to neosporosis occurred in one third of the cases. Remissions were rare. Relapses occurred despite initial improvement. Conclusions: Canine neosporosis presents with diverse neurological clinical signs and MRI features. The disease mainly affects young-to-middle-aged adults with multifocal CNS involvement, and CSF is abnormal in most cases. Review analyses showed that serology titers, serum CK values, CSF TNCC, CSF PCR results and MRI contrast had no prognostic value, while higher CSF TNCC was associated with positive CSF PCR. The single consistent prognostic marker was treatment duration—longer antimicrobial therapy correlated with improved survival. Prognosis remains guarded, but early recognition and prolonged antimicrobial treatment remain key to improving outcomes.