Systemic neosporosis in a dog treated for immune‐mediated thrombocytopenia and hemolytic anemia

Abstract

A 4-year-old male Toy Poodle was presented to the Small Animal Veterinary Hospital of the Faculty of Veterinary Medicine of the Autonomous University of Mexico (FMVZ, UNAM) because of depression, lethargy, and hemorrhages involving several areas of the skin and around the eyes. Hematology data and a bone marrow analysis suggested hemolytic anemia and immune-mediated thrombocytopenia. The dog was treated with prednisone, and after one month the hematology variables improved. However, the dog's clinical condition inexplicably worsened and it was euthanized. On necropsy, there were no relevant findings. However, in histology, multifocal lymphoplasmacytic and histiocytic meningoencephalitis and necrosis, and a protozoan cyst in the cerebellum were identified. In addition, moderate multifocal lymphoplasmacytic and necrotizing pancreatitis, hepatitis, myocarditis, and diffuse lymphoplasmacytic enteritis were observed. Immunohistochemistry of the cerebellum, liver, pancreas, and intestine with a specific antibody against Neospora caninum confirmed the diagnosis of systemic neosporosis. The systemic neosporosis in this dog was most likely caused by reactivation of latent parasites due to prednisone administration during the one month of treatment. It should be kept in mind that in dogs being treated with immunosuppressants for immune-mediated conditions, opportunistic parasites, such as Toxoplasma gondii and N caninum, can be reactivated from a latent state, as it probably happened in the present case.

ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs

“…Leishmaniasis is associated with CH, usually causing granulomatous inflammation . Multiple other systemic diseases can have hepatic involvement with the potential to cause CH ( Neospora , toxoplasmosis, Sarcocystis , histoplasmosis, Mycobacterium , shistosomiasis, visceral larva migrans), but lesions typically are acute and necrotizing and part of a multisystemic disorder …”

“…52,53 Multiple other systemic diseases can have hepatic involvement with the potential to cause CH (Neospora, toxoplasmosis, Sarcocystis, histoplasmosis, Mycobacterium, shistosomiasis, visceral larva migrans), but lesions typically are acute and necrotizing and part of a multisystemic disorder. [61][62][63][64][65][66][67][68][69][70][71][72][73][85][86][87][88]…”

Neosporosis presenting as temporal muscle atrophy in a dog

“…Clinical improvement is unlikely if muscle contracture or rapidly ascending paralysis is present, and severe neurological involvement is a poor prognostic marker (Dubey and others 2009). It is known that dogs on immunosuppressive therapies such as prednisolone can pass from a latent state to clinically active neosporosis (Magaña and others 2015), and in this case the administration of prednisolone at close to immunosuppressive doses may have led to the rapid deterioration seen over the week following initial presentation.…”

Immunsuppressive Therapie bei Hunden und Katzen. Eigenschaften von Wirkstoffen und ihre Anwendung bei verschiedenen immunvermittelten Erkrankungen

“…Opportunistische Infektionen gehören ebenfalls zu den Nebenwirkungen von Ciclosporin (11,13,32,57,58,60,62,65,87,113). Bei 32 Katzen, die mit Ciclosporin behandelt wurden, ließ sich jedoch kein bakterieller Harnwegsinfekt nachweisen (61).…”

“…Fallberichte (13,32,58) und eine experimentelle Studie an 30 Kat-zen (57) machten auf das Risiko von disseminierten Toxoplasmeninfektionen bei Katzen unter Ciclosporin-Therapie aufmerksam. Auch bei Hunden wurden in Einzelfällen unter Ciclosporintherapie eine disseminierte Toxoplasmose und Neosporose beschrieben (60,62,113). Somit sollten Besitzer über die Risikofaktoren für eine Toxpoplasmeninfektion (z.…”