Abstract Histophilus somni is a Gram-negative bacterium that is associated with a disease complex (termed histophilosis) that can produce several clinical syndromes predominantly in cattle, but also in sheep. Histophilosis is well described in North America, Canada, and in some European countries. In Brazil, histophilosis has been described in cattle with respiratory, reproductive, and systemic disease, with only one case described in sheep. This report describes the occurrence of Histophilus somni-associated disease in sheep from Southern Brazil. Eight sheep with different clinical manifestations from five farms were investigated by a combination of pathological and molecular diagnostic methods to identify additional cases of histophilosis in sheep from Brazil. The principal pathological lesions were thrombotic meningoencephalitis, fibrinous bronchopneumonia, pulmonary abscesses, and necrotizing myocarditis. The main clinical syndromes associated with H. somni were thrombotic meningoencephalitis (n = 4), septicemia (n = 4), bronchopneumonia (n = 4), and myocarditis (n = 3). H. somni DNA was amplified from multiple tissues of all sheep with clinical syndromes of histophilosis; sequencing confirmed the PCR results. Further, PCR assays to detect Pasteurella multocida and Mannheimia haemolytica were negative. These findings confirmed the participation of H. somni in the clinical syndromes investigated during this study, and adds to the previous report of histophilosis in sheep from Brazil.

Resumo: As neoplasias no sistema nervoso central (SNC) de animais de companhia são frequentemente diagnosticadas, no entanto dados sobre prevalência são escassos. O objetivo deste estudo foi avaliar retrospectivamente a ocorrência de neoplasias primárias de SNC em cães atendidos em um Hospital-Escola Veterinário e descrever aspectos clínicos, histopatológicos e imuno-histoquímicos dos tumores mais frequentes. Quatorze casos (prevalência de 0,27%) de neoplasias primárias de SNC foram identificados no período de 1998 a 2013 e destes, 11 tiveram o diagnóstico de meningiomas. A idade média dos animais com meningioma foi 10 anos, sendo machos (7/11) e a raça Boxer (3/11) os mais afetados. Sete meningiomas eram espinhais e quatro intracranianos, sendo os principais sinais clínicos alteração na locomoção e convulsões, respectivamente. Metástase pulmonar ocorreu em dois casos. Em seis animais com meningioma espinhal foi realizada a mielografia, sendo que em um também foi realizada a tomografia. Em todos os casos os exames foram efetivos na visualização de desvio ou interrupção da coluna de contraste, com alterações sugestivas da presença de massa. Em cinco animais realizou-se cirurgia exploratória visando a confirmação da suspeita clínica ou retirada da massa, sendo que a sobrevida variou de 85 a 960 dias. Na avaliação histopatológica, os meningiomas foram classificados em transicional (4/11), meningotelial (2/11), papilar (2/11), angiomatoso (1/11), microcístico (1/11) e anaplásico (1/11). Destes, oito (8/11) apresentaram marcação positiva para tricrômio de Masson e um para vermelho congo nas técnicas histoquímicas. No painel imuno-histoquímico, todos os casos apresentaram imunomarcação positiva para vimentina, mas imunomarcação negativa para fator VIII e p53. A imunomarcação para S100 (6/11), GFAP (5/11) e pancitoqueratina (3/11) foi de intensidade variável. Na graduação histológica, dez meningiomas eram grau I e um grau III. O índice médio de proliferação celular foi de 3,2 figuras de mitose e 3,4% avaliando a expressão de Ki-67. Os resultados confirmaram que os meningiomas são a neoplasia primária de SNC mais prevalente em cães, com variação nos subtipos histológicos. A caracterização histoquímica e imuno-histoquímica contribuiu com a determinação do diagnóstico, no entanto, estudos envolvendo a expressão de outros genes são necessários para auxiliar no prognóstico dessas neoplasias.

Abstract: Neoplasias of the central nervous system (CNS) of small animals are frequently diagnosed; however, data relative to prevalence are scarce. The aim of this study was to evaluate retrospectively the occurrence of primary CNS tumors in dogs in a Veterinary Teaching Hospital and describe clinical, histopathological and immunohistochemical aspects of the most common tumors. Fourteen cases of CNS primary neoplasia (prevalence of 0.27%) were identified from 1998 to 2013; from these 11 were diagnosed as meningiomas. The mean age of dogs with meningiomas was 10 years; male (7/11) and the Boxer breed (3/11) were most commonly represented. Seven meningiomas were located in the spinal cord and four intracranially; the main clinical signs were impaired locomotion and seizures, respectively. Pulmonary metastasis was found in two cases. Myelography was performed in six dogs with spinal meningiomas. In these cases it was effective in demonstrating the deviation or interruption of the contrast column. Exploratory surgery to confirm diagnosis or remove the tumor was performed in five animals and the survival rate varies 85 to 960 days. Meningiomas were histologically classified as transitional (4/11), meningothelial (2/11), papillary (2/11), angiomatous (1/11), microcystic (1/11) and anaplastic (1/11). Evaluation of histological grade was performed; 10 meningiomas were classified as grade I and one as grade III. The neoplastic cells of eight tumors (8/11) were positive for Masson's trichrome and one with the Congo red histochemical techniques. The immunohistochemical assays revealed in all tumors a positive immunoreactivity for vimentin but negative staining for factor VIII and p53. Immunolabelling for S100 (6/11), GFAP (5/11) and pancytokeratin (3/11) showed a variable staining intensity. The mean cell proliferation index was 3.2 mitotic figures and 3.4% for Ki-67 immunostaining. The results confirmed that meningiomas are the most frequent primary CNS neoplasia in dogs, with variation in histological subtypes. Histochemical and immunohistochemical characterization contributed to the diagnosis; however, studies of the expression of other genes are necessary to assist with the prognosis of this kind of neoplasia.