Clostridium chauvoei causes blackleg in cattle. The disease has been reported worldwide, and although it can be prevented by vaccination, sporadic cases and occasional outbreaks still occur. We describe a case of blackleg in a 2-y-old, pregnant Gyr cow with in utero transmission to the fetus. The cow had characteristic gross and microscopic lesions of blackleg including widespread necrohemorrhagic and emphysematous skeletal and myocardial myositis, and fibrinous pericarditis. Her uterus contained a near-term, markedly emphysematous fetus with skeletal muscle and myocardial lesions similar to those seen in the dam. Histopathology of dam and fetal tissues revealed numerous gram-positive bacilli, many of them with sub-terminal spores, in multiple tissues. These bacilli were identified as C. chauvoei by immunohistochemistry. Anaerobic culture and fluorescent antibody tests performed on skeletal muscle from both the dam and fetus were positive for C. chauvoei, confirming a diagnosis of blackleg. Blackleg is a so-called endogenous infection, and the currently accepted pathogenesis involves ingestion of spores that are transported to muscle tissues where they lie dormant until anaerobiosis prompts germination. Germinating bacteria are histotoxic, producing severe, local necrosis and ultimately lethal toxemia. This model, however, has not been confirmed experimentally and also fails to explain some cases of the disease. A presumptive diagnosis of blackleg is based on clinical, gross, and histologic findings. Diagnostic confirmation necessitates the detection of C. chauvoei by culture, PCR, or immunodetection methods.

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Blackleg is an infectious disease of cattle and rarely other ruminants, produced by Clostridium chauvoei and characterized by necrotizing myositis. In most cases of blackleg, the large muscles of the pectoral and pelvic girdles are affected, with other skeletal muscles and the heart involved less frequently. We studied 29 blackleg cases selected from the archives of the California Animal Health and Food Safety Laboratory, 1991-2015. Immunohistochemistry was also evaluated to detect C. chauvoei in formalin-fixed, paraffin-embedded (FFPE) tissues of cattle. Nineteen animals had gross and/or microscopic lesions in both skeletal muscle and heart, 9 had lesions in the skeletal musculature alone, and 1 in the heart alone. Gross lesions in the skeletal musculature involved the following muscle groups: hindquarters (n = 8), forequarters (n = 5), neck (n = 5), lumbar area (n = 3), brisket (n = 2), diaphragm (n = 2), abdominal wall (n = 1), thoracic wall (n = 1), and tongue (n = 1). Of the 20 animals that had lesions in the heart, 11 had pericarditis and myocarditis; 7 had pericarditis, myocarditis, and endocarditis; and 1 each had pericarditis and myocarditis. Immunohistochemistry was 100% sensitive to detect C. chauvoei in FFPE skeletal muscle and/or heart of cattle with blackleg. Simultaneous lesions in skeletal musculature and heart were relatively common in blackleg cases in California; the most affected skeletal muscles were those of the hindlimbs.

This study was conducted to determine the seroprevalence of anti-Neospora caninum antibodies and to investigate the risk factors related to seroprevalence in dogs from urban and rural areas with distinct economic activities (milk and coffee production) in Minas Gerais state, Brazil. For this purpose, blood samples from 703 dogs were collected and questionnaires addressing epidemiological aspects were completed by dog-owners. The sera were analysed for anti-N. caninum antibodies by indirect fluorescent antibody tests (IFAT ≥ 1:50). Association between epidemiological aspects and seropositivity in dogs was evaluated with multivariate logistic regression models. A total of 80 (11·4%) dogs tested positive for N. caninum. In the multivariate logistic regression models, dogs aged >4 years, dogs used as guard dogs, dogs that spontaneously hunt, and history of bovine abortion were found to be greater risk factors for canine N. caninum infection. When we considered only dogs from rural areas, an association with seroprevalence was seen for milk farms, dogs not fed with commercial food, dogs that hunt, and dogs used as guard dogs.

Este estudo teve como objetivo determinar a prevalência e achados anatomopatológicos de tumores primários e metastáticos do coração ou de tecidos da base do coração, diagnosticados em caninos do Sul de Minas Gerais. O diagnóstico foi realizado mediante análise histopatológica e imuno-histoquímica das neoplasias. Durante os anos de 1994-2009, foram realizadas 2397 necropsias em caninos. Neoplasias no coração foram detectadas em 31 cães (1,29%), onde, sete (22,58%) eram primárias e 24 (77,42%) metastáticas. As neoplasias diagnosticadas como primárias do coração foram o hemangiossarcoma (1/7) e o mixoma (1/7); e como primárias da base do coração o quimiodectoma (3/7) e o carcinoma de tireoide ectópica (2/7). A frequência foi maior em cães machos (5/7), da raça Boxer (3/7) e com idade média de 9,7±1,88 anos. Nas neoplasias metastáticas, a frequência foi maior em fêmeas (15/24), em cães da raça Rottweiler (7/24) e a idade média foi de 7,5±3,23 anos, sendo o linfoma de células T a neoplasia metastática de maior ocorrência (7/27).

Este estudo estabelece a soroprevalência de Neospora caninum e Toxoplasma gondii em rebanhos caprinos no Sul de Minas Gerais e verifica a sua associação com o desempenho reprodutivo dos rebanhos analisados, uma vez que não há dados sobre neosporose em caprinos neste Estado. Amostras de soro de 401 caprinos provenientes de 11 propriedades foram submetidas à reação de imunofluorescência indireta anti-N. caninum e T. gondii. A prevalência média de animais positivos foi de 10,7% e 21,4%, respectivamente. Houve diferença significativa entre as faixas etárias. Neste quesito os maiores índices de positividade, para ambos os parasitas, foram observados nos caprinos acima de três anos de idade. Estes apresentaram uma probabilidade 2,6 e 4,8 maior, em relação aos animais de até um ano de idade, para N. caninum e T. gondii, respectivamente. No teste T não houve associação positiva entre as médias de prevalência de N. caninum (p=0,553) e T. gondii (p=0,098) com a ocorrência de problema reprodutivo nos rebanhos. Porém, propriedades com histórico de problemas reprodutivos apresentaram uma média de reagentes para N. caninum de 18,64%, se comparadas a 13,97% de criatórios que não relataram essas alterações. Quando os problemas reprodutivos foram separados em categorias a relação entre a ocorrência de aborto e a soroprevalência de N. caninum e de T. gondii foi significativa (p<0,05) por meio dos testes Exato de Fisher e Qui-quadrado. Não houve diferença (p>0,05) entre as médias de prevalência de T. gondii e o acesso de gatos ao rebanho no teste T. Entretanto, a média de prevalência nas propriedades em que os gatos tinham acesso foi de 31,01%, se comparada a 17,34% em criatórios onde não existiam gatos. Foi constatado o acesso de cães em 100% das propriedades. Os resultados obtidos neste estudo demonstram que N. caninum e T. gondii infectam caprinos no Sul de Minas Gerais e que estes parasitas podem estar associados à ocorrência de abortos nessa espécie animal.

BackgroundNeospora caninum is an apicomplexan protozoan that is considered one of the main agents responsible for abortion in ruminants. The lesions found in the central nervous system (CNS) of aborted fetuses show multifocal necrosis, gliosis, and perivascular cuffs of mononuclear cells, but the inflammatory and glial cells have not been immunophenotypically characterized. The lesions in the CNS of infected adult animals have rarely been described. Therefore, in this study, we characterized the lesions, the immunophenotypes of the inflammatory and glial cells and the expression of MHC-II and PCNA in the CNS of goats infected with N. caninum. The CNS of eight aborted fetuses and six adult male goats naturally infected with N. caninum were analyzed with lectin histochemistry (RCA1) and immunohistochemistry (with anti-CD3, −CD79α, −GFAP, −MHC-II, and -PCNA antibodies). All animals were the offspring of dams naturally infected with N. caninum.ResultsThe microscopic lesions in the CNS of the aborted fetuses consisted of perivascular cuffs composed mainly of macrophages (RCA1+), rare T lymphocytes (CD3+), and rare B lymphocytes (CD79α+). Multifocal necrosis surrounded by astrocytes (GFAP+), gliosis composed predominantly of monocytic-lineage cells (macrophages and microglia, RCA1+), and the cysts of N. caninum, related (or not) to the lesions were present. Similar lesions were found in four of the six male goats, and multinucleate giant cells related to focal gliosis were also found in three adult goats. Anti-GFAP immunostaining showed astrocytes characterizing areas of glial scarring. Cysts of N. caninum were found in three adult male goats. The presence of N. caninum was evaluated with histopathology, immunohistochemistry, and PCR. Immunohistochemistry demonstrated anti-PCNA labeling of macrophages and microglia in the perivascular cuffs and the expression of MHC-II by microglia and endothelial cells in the CNS of the aborted fetuses and adult male goats.ConclusionsMacrophages and microglia were the predominant inflammatory cells in the CNS of aborted fetuses and healthy adult male goats infected with N. caninum. Activated astrocytes were mainly associated with inflamed areas, suggesting that astrocytes were involved in the resolution of the lesions.

Um surto de compactação primária de abomaso associada ao consumo de silagem de girassol ocorreu num rebanho bovino leiteiro do estado de Minas Gerais, do qual seis de 21 vacas secas em fase final de gestação e que recebiam silagem de girassol morreram. Os bovinos que adoeceram apresentaram distensão abdominal, fezes ressecadas e escassas e, nos bovinos que morreram, eram pastosas, escuras e fétidas; nesses havia também desidratação acentuada e palidez de mucosas. Três bovinos foram necropsiados e os achados patológicos eram constituídos principalmente por distensão acentuada do abomaso associada a grande quantidade de conteúdo alimentar ressecado coberto por coágulos de sangue. No abomaso havia úlceras, com perfuração da parede em um dos bovinos. A alimentação de bovinos de maior exigência nutricional com silagem de girassol de características indesejáveis como única fonte de volumoso foi o principal fator para a compactação de abomaso nos casos apresentados.