Clinical, pathological and immunohistochemical findings of sheep infected with rabies virus

Abstract

ABSTRACT. Bassuino D.M., Konradt G., Mari C., Cruz R.A.S., Boos G.S., Gomes D.C., Petinatti S.P. & Driemeier D. [Clinical, pathological and immunohistochemical findings of sheep infected with rabies virus.] Achados clínicos, patológicos e imuno-histoquímicos em ovinos com raiva. Revista Brasileira de Medicina Veterinária, 38(1):86-90, 2016. Programa de Pós-Graduação em Ciências Veterinárias, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brasil. E-mail: davetpat@ufrgs.br In this article we described three cases of rabies in sheep in Rio Grande do Sul state, Brazil. Refrigerated samples of encephalon and spinal cord of two sheep, as well as one sheep sent to necropsy, with history in common of progressive neurological signs were referred to histopathological analyses. Samples from the brain and spinal cord were collected and routinely processed for hematoxylin and eosin (HE) and immunohistochemistry (IHC). To evaluate and to quantify the lesions, and also for immunohistochemistry, serial sections of the cerebral cortex, obex, thalamus, hippocampus, cerebellum and spinal cord were made. Refrigerated samples of brain were sent to direct immunofluorescence (DIF) exam for the detection of viral antigen. The histological findings were characterized by nonsuppurative meningoencephalitis and meningomyelitis with perivascular infiltrate, microgliosis, hemorrhage and congestion. Positive immunostaining was observed in the three sheep analyzed with signals ranging from discrete to accentuated. At the DIF examination, two sheep were positive and one was negative. It is concluded that rabies should be included in the differential diagnosis of diseases from the central nervous system of sheep, even if it is rarely described in this species.