A multimodal approach to diagnosis of neuromuscular neosporosis in dogs

Alf, Vanessa ; Tirrito, Federica; Fischer, Andrea; Cappello, Rodolfo; Kiviranta, Anna‐Mariam; Steinberg, Tanja A.; Poli, Federica; Stotz, Felix; Del Vecchio, Omar V.; Dörfelt, Stefanie; Falzone, Cristian; Knittel, André; Loderstedt, Shenja; Mercuriali, Edy; Tabanez, Joana; Zagarella, Paolo; Matiasek, Kaspar; Rosati, Marco (2024): A multimodal approach to diagnosis of neuromuscular neosporosis in dogs. Journal of Veterinary Internal Medicine, 38 (5). pp. 2561-2570. ISSN 0891-6640

Abstract

Background
Early diagnosis of neosporosis in dogs is challenging.

Objectives
To evaluate the feasibility of a compound multimodal testing approach for diagnosing in dogs neuromuscular and combined forms of neosporosis.

Animals
A total of 16 dogs diagnosed with solely neuromuscular neosporosis or with a combination of neuromuscular and central nervous system neosporosis.

Methods
Retrospective review of clinical signs, laboratory findings, treatment, and outcome with focus on the diagnostic utility of different tests. Development of a chromogenic in situ hybridization (ISH) assay for the identification of Neospora caninum in paraffin-embedded muscle samples.

Results
13/16 dogs had only neuromuscular signs of neosporosis, 3/16 had disease signs with concomitant central nervous system (CNS) involvement. Serology was performed in 15/16, with 10/15 showing titers >1 : 160 at admission. PCR on muscle samples detected N. caninum DNA in 11/16. Immunohistochemistry (IHC) detected N. caninum in 9/16 and ISH in 9/16. Histopathology revealed inflammatory myopathy in 10/16, necrotizing myopathy in 5/16, borderline changes in 1/16 and tachyzoites in 9/16. In 4 cases, N. caninum infection was confirmed with all 5 diagnostic methods, 3 cases with 4, 2 with 3, 6 with 2, and 1 animal with 1.

Conclusions and Clinical Importance
Diagnosis of N. caninum infection should rely on a multimodal diagnostic approach and negativity of 1 single test should not allow for exclusion. Serology in combination with direct parasite identification via histopathology, DNA via PCR, or both modalities, appears a reliable diagnostic approach.

• Doc-Type: Article (LMU)
• Organisational unit (Faculties): 08 Veterinary Medicine > Centre for Clinical Veterinary Medicine > Institut für Tierpathologie
• DFG subject classification of scientific disciplines: Life sciences
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 491502892