Flademir Wouters

An outbreak of aflatoxin poisoning in dogs associated with aflatoxin B1–contaminated maize products

An aflatoxicosis outbreak affected 65 dogs from 9 different farms after they were fed diets with cooked corn meal as a common ingredient. Of the dogs, 60 died. Numerous dogs died on additional farms, but those dogs were not included in the study. The farmers acquired the contaminated maize products, in the form of whole corn grain or as corn meal, from the same supplier. The corn product was mixed with meat that was left over from home or commercial rations to form corn polenta, which was fed to the dogs. Necropsy was performed on 3 dogs. Two of the dogs died after a few days of refusing food, showing anorexia, polydipsia, icteric mucous membranes, hematemesis, hematochezia, or melena, and bleeding of the skin, eye, ear, and mouth. The primary necropsy findings included jaundice, hemorrhages in several organs, and yellowish enlarged liver with enhanced lobular pattern. The dog that experienced chronic ascites had a yellowish liver with reduced volume, irregular surface, and increased consistency. The main histological findings included hepatocyte fatty degeneration, biliary duct hyperplasia, cholestasis and, in the chronic case, hepatic fibrosis. High-performance liquid chromatography analysis of the corn meal from 2 affected farms revealed 1,640 ppb and 1,770 ppb of aflatoxin B1, respectively. The current study demonstrates an additional way that dogs can be exposed to, poisoned, and killed by aflatoxin.

Fatal systemic toxoplasmosis in Valley quail (Callipepla californica)

Highlights • This is the first report of systemic fatal toxoplasmosis in Valley quail.• Toxoplasma gondii was molecularly identified as belonging to ToxoDB-PCR-RFLP #87.• It caused a generalized disease with necrotic lesion in liver, heart, spleen, lungs, trachea and bone marrow, with large numbers of tachyzoites stained positively with polyclonal antiserum to T.u2009gondii.

Intoxicação espontânea por Cestrum intermedium em bovinos no Sudoeste do Estado do Paraná

Sao descritos surtos de intoxicacao espontânea por Cestrum intermedium em bovinos leiteiros do Municipio de Salgado Filho, sudoeste do Estado do Parana, com morte de dezesseis bovinos de um total de 72 de quatro pequenas propriedades. O historico obtido nessas propriedades incluia curso clinico agudo, com morte em menos de 24 horas. Em todas foram observadas elevada lotacao por area com escassa pastagem disponivel e grande quantidade de plantas arbustivas identificadas como C. intermedium e com sinais de terem sido consumidas pelos animais. Dois bovinos foram necropsiados e os achados mais importantes foram congestao de mucosas conjuntivais e vulvovestibular; hemorragias e evidenciacao do padrao lobular no figado; hemorragia, congestao e edema pulmonares; congestao esplenica e encefalica, alem de hemorragias multifocais no coracao. Amostras de tecidos desses bovinos foram avaliadas, com alteracoes histologicas importantes no figado, caracterizadas por necrose acentuada de hepatocitos e hemorragia, indicativas de hepatopatia toxica aguda e, no encefalo, foram observadas alteracoes astrocitarias em substância branca de cerebro e cerebelo e na substância cinzenta do cerebelo, caracterizadas por tumefacao celular com citoplasma amplo e eosinofilico, nucleo picnotico, ora excentrico. Essas alteracoes astrocitarias foram evidenciadas pela tecnica de imuno-histoquimica (IHQ), com imunomarcacao fortemente positiva para os anticorpos anti-proteina S100 (anti-S100) e anti-proteina glial fibrilar acida (anti-GFAP). O trabalho visa enfatizar em lesoes encefalicas relacionadas a hepatotoxicidade aguda em bovinos.

Caracterização imuno-histoquímica das alterações encefálicas em bovinos com hepatopatia tóxica por Senecio sp

Senecio spp. poisoning is an important cause of illness and death of cattle in Rio Grande do Sul, Brazil, and is often manifested by neurologic clinical signs and histological brain changes. Histological evaluation was performed on liver and brain samples of ten cattle naturally poisoned by Senecio sp. Samples of cerebrum, brainstem and cerebellum were stained with periodic acid-Schiff (PAS), and immunohistochemistry was carried out, employing anti-fibrillary acidic protein (GFAP), anti-S100 protein and anti-vimentin antibodies. The histological finding in the brain included mild to severe vacuolation in the white matter and the junction of gray and white matter, characterized as spongy degeneration. Histochemical and immunohistochemical staining revealed no significant findings compared with the brains of eleven adult cattle without liver and/or brain changes used as controls.

Malignant peripheral nerve sheath tumor as a cause of chronic cardiac insufficiency in cattle

Chronic cardiac insufficiency was associated with a malignant peripheral nerve sheath tumor in a cow. An eight-year-old cow developed a progressive condition (over a period of three months) characterized by an enhanced abdominal volume, reluctance to move, a positive jugular pulse, watery diarrhea and death. At necropsy, moderate subcutaneous edema and an enhanced hepatic lobular pattern were observed. A 23x20x11 cm firm, grayish-white mass adhered to and infiltrated the right atrium. Multiple firm, yellowish-white nodules of 0.5 to 12 cm in diameter were diffusely scattered in the epicardium and parietal pericardium. Histologically, the tumor was poorly circumscribed with foci of infiltration of the myocardium. The neoplastic cells had two major histologic patterns, Antoni types A and B. Within occasional foci, pleomorphic cells with an epithelioid appearance were present in addition to multinucleated cells with periodic acid Schiff (PAS)-positive cytoplasmic globules. Foci of cartilaginous and granular differentiations were interspersed among the neoplastic cells. Multiple vessels presented wall hyalinization and tumoral embolus. Large necrotic foci with mineralization and cholesterol clefts were also observed. Immunohistochemically, the tumor was positive for S100 protein, vimentin and neuron-specific enolase labeling.

Canine papillomatosis: a retrospective study of 24 cases (2001-2011) and immunohistochemical characterization

Foi realizado um estudo retrospectivo de 24 casos de papilomas em caes diagnosticados no periodo de janeiro 2001 a marco de 2011, bem como a sua caracterizacao imuno-histoquimica (IHQ). Caes sem raca definida foram os mais afetados, a idade media foi de 3,1 anos, com variacao de 6 meses a 10 anos e nao houve predilecao sexual. Quanto a localizacao das lesoes, 75,0% estavam na pele, 16,7% no labio e 8,3% em palpebra. Na avaliacao histologica havia proliferacao papilar exofitica do epitelio escamoso em 87,5% e papilar endofitica (invertido) em 12,5%. O tumor era caracterizado por hiperplasia do estrato espinhoso (87,5%) com coilocitos (70,8%) e inclusoes intranucleares basofilicas palidas (8,3%); o estrato granular estava proeminente com grande quantidade de grânulos de querato-hialina (95,8%); e havia hiperqueratose do estrato corneo (100%). Na avaliacao IHQ para Papillomavirus houve marcacao nos estratos granuloso e corneo em 83,3%. Estes achados indicam que os papilomas em caes sao causados por Papillomavirus, as lesoes epiteliais sao decorrentes do efeito citopatico viral, as particulas virais estao no nucleo das celulas e corpusculos de inclusao sao raros.

Brain lesions associated with acute toxic hepatopathy in cattle

Samples of the liver, telencephalon, brainstem, and cerebellum were obtained from 22 bovids suffering from spontaneous or experimental acute toxic liver disease. Perreyia flavipes larvae, and leaves of Cestrum corymbosum, Cestrum intermedium, Dodonaea viscosa, Trema micrantha, and Xanthium cavanillesii were the causal agents in the disorders studied. Hematoxylin and eosin and periodic acid–Schiff staining, as well as anti-S100 protein (anti-S100), anti–glial fibrillary acidic protein (anti-GFAP), and anti-vimentin immunostaining were used to evaluate the brain sections. Astrocytic changes were observed in all samples and were characterized by swollen vesicular nuclei in gray (Alzheimer type II astrocytes) and white matter; and by abundant eosinophilic or vacuolated cytoplasm with pyknotic nuclei in the white matter. These changes were evidenced by anti-S100 and anti-GFAP immunostaining. Our study demonstrates major changes in astrocytes of cattle that died with neurologic clinical signs as the result of acute toxic liver disease.

Diagnóstico imuno-histoquímico e caracterização anatomopatológica de Mycoplasma gallisepticum em galinhas de subsistência

Avian mycoplasmosis is caused by bacteria from the Mycoplasmataceae family. Mycoplasma gallisepticum (MG) is the most pathogenic and economically significant species affecting poultry. The aim of this study was to use the immunohistochemistry technique (IHC) as a diagnostic method for the MG infection in poultry. In this report we described two outbreaks of mycoplasmosis caused by MG in free-range chickens. Clinical signs were characterized by prostration, decreased appetite, difficult breathing, nasal and ocular discharge. Necropsy findings were serous secretion in conjunctiva (7/10) and seioses (4/10), edema and caseous exudate; air sacs thickened with foam and caseous exudate (6/10); trachea diffusely reddish (4/10); lungs with 0.5 cm whitish spots (2/10); and pericardial sac with fibrin exudate (2/10). Histologically was observed a lymphoplasmacytic hyperplastic acute tracheitis (10/10), seiositis (5/5) and conjunctivitis (3/4); fibrinonecrotic bronchopneumonia (5/10); acute fibrinous pericarditis (2/10); and fibrinonecrotic aerosaculitis (1/1). IHC anti-MG stained in the extracellular surface of ciliated brush border and/or in the top of epithelium of trachea (10/10), bronchi (5/10) and sinuses (4/5). In seven out of ten cases it was possible to detect MG by real-time PCR from tracheal swabs. IHC anti-MG used as a diagnostic method showed good correlation with clinical signs, lesions and real-time PCR results.

Pneumotoxicosis in Sheep Caused by Ingestion of Trema Micrantha

Trema micrantha, a fast-growing tree distributed throughout the Americas, produces palatable leaves that have been associated with hepatic necrosis and acute death when consumed by livestock. This report describes fatal pulmonary disease of sheep triggered by consumption of Trema micrantha. Affected sheep had severe progressive dyspnea for a few days before death. Subcutaneous and mediastinal emphysema, reddened lungs, interalveolar septal thickening, and diffuse type II pneumocyte proliferation were the main pathological findings. After ingesting 77.5 and 102.5 g/kg (divided in 3 doses, at 30-day intervals) of T. micrantha leaves, 2 additional sheep developed the same condition. These findings indicate that T. micrantha toxicosis should be considered in the differential diagnosis of ovine respiratory disease.

Caracterização patológica e imuno-histoquímica das lesões de actinobacilose em bovinos

Actinobacillosis is a not contagious infectious disease, usually chronic, and characterized by pyogranulomatous inflammatory reaction that occurs in cattle and is less common in sheep, pig, and horse. Soft tissues of head, mouth, and regional lymph nodes are affected. In this retrospective study, lesions suggestive of Actinobacillosis from 18 cases of anatomopathologic bovine samples were retrieved from the archives of Setor de Patologia Veterinaria of Universidade Federal do Rio Grande do Sul, from January 1997 to May 2011. The lesions were classified histologically, evaluated by histochemistry, and immunohistochemistry (IHC) in order to standardize inflammatory infiltration. The most frequent histological findings were typical pyogranulomas of actinobacillosis contained radiating eosinophilic clubs surrounded by neutrophils, macrophages, lymphocytes and abundant fibrous connective tissue. Gram-negative coccobacillus bacteria were shown in all lesions by Gram stain. Abundant macrophages were immunopositive for CD68, especially epithelioid cells and multinucleated giant cells. In addition, a positive immunostaining for CD3 (T lymphocyte) was observed in proportion of 1:3 in lymphocyte inflammatory infiltration, while IHC for CD79αcy (B lymphocytes) was obtained in proportion of 2:3. These results indicated that B lymphocytes are the majority of lymphocyte in the inflammatory area.