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Cardiomiopatia dilatada (CMD) é uma condição que afeta o miocárdio, raramente relatada em porcos. A DCM é caracterizada por dilatação ventricular, que resulta em disfunção sistólica e disfunção diastólica secundária e pode levar a arritmias e insuficiência cardíaca congestiva fatal. Este estudo descreve os achados clínicos, patológicos, químicos e toxicológicos da CMD em suínos de creche através de estudos naturais e experimentais. Investigaram-se três granjas com surtos de mortalidade por CMD através de exames de necropsia (catorze suínos), microscópicos, virológicos, químicos e toxicológicos para a detecção da etiologia. O estudo experimental foi conduzido com nove leitões de 40 dias de idade, divididos em três grupos de três leitões cada. O grupo 1 foi alimentado com a dieta suspeita dos casos naturais; o 2 com metade da dieta suspeita e metade de dieta controle; e o 3 recebeu apenas a dieta controle. Sinais clínicos foram registrados. Todos os suínos foram submetidos a eutanásia, necropsia para a coleta de amostras para exames laboratoriais após 15 dias do início do experimento. Na necropsia, todos os leitões dos casos naturais apresentavam dilatação cardíaca bilateral associada a padrão lobular hepático aumentado (fígado de noz-moscada) e edema pulmonar. Microscopicamente, o coração revelou hipertrofia severa e vacuolização de cardiomiócitos, bem como desordem de miofibras. A análise da ração demonstrou que o farelo de soja apresentava baixa solubilidade o que indica baixa qualidade. Após a substituição da ração suspeita, os porcos clinicamente doentes recuperaram e a mortalidade cessou. No estudo experimental, dois leitões do grupo 1 apresentaram tosse, dispneia e diarreia. Na necropsia, esses animais apresentavam lesões macroscópicas e macroscópicas similar aos casos naturais. A CMD nutricional em suínos pode estar associado à dieta com farelo de soja de baixa qualidade, como foi confirmado através de um estudo experimental. Dilated cardiomyopathy (DCM) is a condition that affects the myocardium, seldom reported in pigs. The DCM is characterized by ventricular dilation, which results in systolic and secondary diastolic dysfunction and can lead to arrhythmia and fatal congestive heart failure. This study described the clinical, pathological, chemical and toxicological findings of nutritional dilated cardiomyopathy (DCM) in nursery pigs through natural and experimental studies. Naturally occurring cases of DCM in three swine farms were investigated through necropsy (fourteen pigs), microscopic, virological, chemical and toxicological exams for the detection of the etiology. The experimental study was conducted with nine 40 days-old piglets, which were divided into three groups of three piglets each. Group 1 was fed with the suspected diet of the naturally occurring cases, Group 2 with half of the suspected diet and half of a control diet, and Group 3 received only the control diet. Clinical signs were recorded. All pigs were submitted of euthanized, necropsie and collection sample for laboratories exams, after 15 days of experiment onset. At the necropsy, all naturally occurring cases had bilateral cardiac dilatation associated to hepatic enhanced lobular pattern (nutmeg liver) and lungs edema. Microscopically, the heart revealed severe hypertrophy and vacuolization of cardiomyocytes, as well as myofiber disarray. Feed analysis revealed low-quality standard soybean meal. After the suspected feed was replaced, clinically ill pigs recovered, and mortality ceased. At the experimental study, two piglets from Group 1 had cough, dyspnea and diarrhea. At the necropsy, these animals had similar gross and microscopic lesions to the natural cases. The nutritional DCM in pigs may be associated to the diet with low-quality soybean meal, as it was further confirmed through an experimental study.

Porcine encephalomyelitis can be associated with many etiologies, including viral agents, such as Porcine teschovirus (PTV), Porcine sapelovirus (PSV), and Porcine astrovirus (PoAstV). In this study, we investigated the presence of these viruses in a neurological disease outbreak in a swine farm in Southern Brazil. The piglet production farm unity had 1200 weaning piglets, and 40 piglets with neurological signs such as motor incoordination, paresis, and paralysis of hind limbs, with an evolution time of approximately 4 days. Among these, 10 piglets were submitted to postmortem examination. Gross lesions were restricted to a mild enlargement of the nerve roots and ganglia of spinal cord segments. The microscopic lesions were characterized by nonsuppurative encephalomyelitis and ganglioneuritis with evident neuronal degeneration and necrosis. Samples of the central nervous system (CNS), cerebrospinal fluid, and feces were collected and submitted to molecular analysis. PTV was identified in all samples of the CNS, while eight of the piglets were also positive for PSV, and seven were positive for Porcine enterovirus (EV-G). PoAstV was identified in a pool of feces of healthy animals used as controls. This study demonstrates the occurrence of encephalomyelitis associated with PTV on a swine farm in Southern Brazil, as well as the presence of other viruses such as PSV, EV-G, and PoAstV in the swineherd. Sequences of the fragments that were previously amplified by PCR showed a high similarity to PTV 6. Herein, we describe the first case report of severe swine polioencephalomyelitis associated with PTV in South America.

Made available in DSpace on 2018-12-11T17:17:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) On a farm in southern Brazil, four lambs in a flock of 300 Texel sheep were born with bilateral blindness. They revealed bilateral occlusion of the eyelids and were unresponsive to external visual stimuli and were disoriented when walking. A post-mortem examination revealed bilateral occlusion of the eyelids and, microscopically, total or partial absence of the lens was observed. Blood samples from 20% of the herd (61/300) were sent for molecular analysis. The four affected lambs were homozygous (C/C) for a mutation (single-nucleotide polymorphism c.338G > C) in the PITX3 gene, and 26.2% (16/61) of the herd, including the two ewe and two ram parents, were heterozygous (G/C). Based on clinical, pathological and molecular analysis, it was possible to determine the existence of hereditary microphthalmia in Texel lambs associated with the c.338G > C SNP in the PITX3 gene for the first time in Brazil. The result of this study provides a warning to veterinarians and breeders, emphasizing the importance of considering this disease in the differential diagnosis of congenital diseases in the Brazilian Texel flock. Faculdade de Medicina Veterinária Universidade Federal do Rio Grande do Sul (UFRGS) Departamento de Patologia Veterinária, Av. Bento Gonçalves 9090 Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista (UNESP) Campus Botucatu Departamento de Clínica Veterinária, Rua Prof. Doutor Walter Mauricio Correa s/n Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista (UNESP) Campus Botucatu Departamento de Clínica Veterinária, Rua Prof. Doutor Walter Mauricio Correa s/n CAPES: 1328442

Rotavirus (RV) is an important viral pathogen causing diarrhea in piglets and other mammals worldwide. We describe 34 cases from 4 diarrheal outbreaks caused by RV in unvaccinated farrowing units in southern Brazil from 2011 to 2013. We performed autopsy, histologic examinations, bacterial culture, RV immunohistochemistry (IHC), and enteric virus detection through molecular assays for rotavirus A, B, and C, transmissible gastroenteritis virus, porcine epidemic diarrhea virus, sapovirus, norovirus, and kobuvirus. Histologically, villus atrophy (29 of 34) and epithelial vacuolation (27 of 34) occurred in all 4 outbreaks. Cell debris in the lamina propria occurred in 20 cases, mostly from outbreaks A (8 of 11), C (4 of 6), and D (7 of 11). IHC was positive for RV in 21 of 34 samples. RT-PCR was positive for RV in 20 of 30 samples; RV-C was the most frequently detected RV ( n = 17). Kobuvirus was detected in 11 samples, and, in 3 of them, there was single detection of this enteric virus.

Porcine circovirus type 2 (PCV2) is associated with multiple clinical syndromes in pigs, known as porcine circovirus diseases. This work describes an outbreak of porcine circovirus diseases with severe lesions affecting the skeletal muscle. Ninety-two pigs had apathy, weight loss, and diarrhea over a clinical course of 7 to 10 days. Approximately 30 of the pigs had stiff gait, muscle weakness, hind limb paresis, and recumbency. Twelve of the 92 pigs were necropsied, and 4 had pale discoloration of skeletal muscles with microscopic lesions of granulomatous necrotizing myositis. Immunohistochemistry of skeletal muscle showed that PCV2 antigen was located primarily in the cytoplasm and nuclei of macrophages, lymphocytes, and multinucleated giant cells, with a lower amount in the cytoplasm of endothelial cells, necrotic fibers, and satellite cells. Affected muscle samples were polymerase chain reaction–positive for PCV2 and the amplicon exhibited 99% identity with sequences belonging to the PCV2b genotype. Locomotor clinical signs and granulomatous necrotizing myositis should be considered as another expression of PCV2 infection in pigs.

Background:Actinobacillosis in adult horses is rare, and is often associated with infection due to Actinobacillus equuli subsp. equuli, which is a commensal organism inhabiting the oral cavity of healthy animals. It is an opportunistic pathogen, and the infection usually occurs secondary to another primary disease or due to predisposing factors such as pre-existing lesions, mainly in the oral cavity. Infection may be associated with peritonitis, bacterial endocarditis, pneumonia, enteritis, infectious periorchitis, abortion, and septicemia. This paper aims to describe the clinical, microbiological, and pathological aspects of actinobacillosis in the oral cavity of a horse.Case:A case of actinobacillosis has been reported in a 22-year-old gelding Quarter Horse. According to the owner, the animal presented with progressive weight loss during the previous three months, and leakage of food from the oral cavity. Examination of the oral cavity revealed sharp enamel overgrowths, which had been corrected during a previous dental procedure. However, five days after the procedure, the animal developed halitosis. Ceftiofur sodium (4.4 mg/kg intramuscularly, every 24 h) was prescribed; two days after the commencement of antimicrobial therapy, the animal presented with sialorrhea, bilateral submandibular lymphadenomegaly, protrusion of the tongue, edema of the base of the tongue, cheeks, and gums, in addition to black-colored sores and scales in the oral mucosa, particularly affecting the base of the tongue and gums. Samples from ulcerative lesions found at the base of the tongue and gums were collected using sterile swabs, and culture and antibiogram were requested. Microbiological culture led to the growth of small colonies measuring less than 5 mm in diameter, that were non-hemolytic, slightly whitish in color but non-opaque, smooth and bright in appearance. These were identified as gram-negative rods on microscopy, and further characterized as Actinobacillus equuli subsp. equuli based on the phenotypic and biochemical findings. The antibiogram revealed sensitivity of the organisms to cephalothin and doxycycline, intermediate sensitivity to amoxicillin, and resistance to florfenicol, metronidazole, clindamycin, and sulfazotrim. The complete blood count revealed anemia with a reduction in hemoglobin (10.1 g/dL) and hematocrit (27.9%), neutrophilia (10.670 x 10³ /mm³), and lymphopenia (330 x 10³ /mm³). Decrease in serum albumin (2.0 g/dL) and alkaline phosphatase (91 IU/L), and increase in globulin (4.9 g/dL), aspartate aminotransferase (361 4 IU/L), and urea (123.8 mg/dL) were noted on biochemical analyses. Two days after the onset of acute clinical signs, the animal died; necropsy revealed severe, subacute, fibronecrotic glossitis associated with myriads of basophilic bacteria.Discussion:This report describes an infection of the oral cavity by Actinobacillus equuli subsp. equuli following a dental procedure, a finding compatible with the opportunistic nature of these bacteria. The presence of enamel overgrowths resulted in the formation of traumatic lesions on the oral mucosa and tongue that favored colonization of the bacteria. The case of equine glossitis reported in this study had a similar clinical presentation to the classic actinobacillosis in cattle, also known as “wooden tongue”, an infection caused by Actinobacillus lignieresii; common symptoms in cattle include oral edema, sialorrhea, and dysphagia.

A enteropatia proliferativa (EP), também conhecida como ileíte, é uma doença causada pela bactéria Lawsonia intracellularis, que é caracterizada por diarreia com redução do ganho de peso. O objetivo deste trabalho é descrever um surto de EP em coelhos na região sul do Brasil. A propriedade possuía 700 coelhos, durante o período do surto. O quadro clínico caracterizava-se por diarreia severa, desidratação e apatia. Realizou-se o exame de necropsia em 33 coelhos, e as alterações macroscópicas mais evidentes eram; alças intestinais acentuadamente distendidas por gás e fezes líquidas, além de serosa rugosa e parede intestinal moderadamente espessada. Na análise histopatológica do intestino delgado visualizou-se marcada hiperplasia de enterócitos de criptas, moderada diminuição do número de células caliciformes e microabscessos de criptas. A etiologia das lesões foi confirmada pela técnica de impregnação pela prata (Warthin-Starry), evidenciando bactérias vibrioides compatíveis com L. intracellularis no ápice de enterócitos das criptas intestinais. Ainda, foi obtida imunomarcação positiva de enterócitos de criptas na imuno-histoquímica com anticorpo anti-L. intracellularis e a PCR positiva em amostras de intestino. Proliferative enteropathy (PE), also known as ileitis, is a disease caused by the bacterium Lawsonia intracellularis. This disease is characterized by diarrhea and ill-thrift. The aim of this study is to describe a PE outbreak in rabbits that occurred in Southern Brazil. The farm had 700 rabbits at the time the outbreak occurred. The clinical signs were severe diarrhea, dehydration, and apathy. Necropsy was performed in 33 rabbits, and the most evident macroscopic findings were thickening of the intestinal wall, intestinal loops distended by large amounts of gas, and liquid feces. Histopathological examination demonstrated a marked proliferation of enterocytes in intestinal crypts, decrease number of goblet cells, and crypts microabscesses. Silver impregnation technique (Warthin-Starry) demonstrated in intestinal crypts inside of enterocytes cytoplasm, curved vibrioid bacteria compatible with L. intracellularis. Immunohistochemical staining with anti-L. intracellularis confirmed the agent presence. PCR was performed and L. intracellularis was confirmed as the etiological agent.

Skin diseases in pigs can negatively impact the production. They cause losses related to the death of the affected pigs, to the cost with the treatment, growth retardation and condemnations in the slaughterhouses. This study was developed to determine the frequency and describe the histopathological findings of skin diseases in pigs in different age groups through a retrospective study from 2006 to 2018. A total of 154 conclusive cases were analyzed, including skin restricted diseases (allergic dermatitis, exudative epidermitis, vesicular dermatitis, pityriasis rosea, swinepox, follicular cyst, papilloma and scrotal hemangioma) or skin lesions secondary to systemic diseases (erysipelas, porcine dermatitis and nephropathy syndrome (PDNS), bacterial septicemia and multiple hemorrhages without definite cause). The skin lesions were classified as bacterial (46.1%), viral (26.6%), allergic (12.3%), neoplastic (1.3%) and others (13.6%). Swine erysipelas was the most frequent diagnosis (47/154), followed by PDNS (23/154), allergic dermatitis (19/154) and exudative epidermitis (15/154). Vesicular dermatitis (9/154), pityriasis rosea (9/154), septicemia with cutaneous manifestations (9/154), swinepox (9/154) and multiple hemorrhages without definite cause (7/154) were also observed. Follicular cyst (3/154), hyperkeratosis without definite cause (2/154), papilloma (1/154), and scrotal hemangioma (1/154) were less frequently described. Of the conclusive diagnosis, age was reported in 138 cases, with the highest frequency of skin lesions observed at the inspection process during slaughter (56/138). RESUMO: As doenças de pele em suínos podem impactar negativamente a produção. Estas causam perdas relacionadas à morte dos acometidos, a custo com tratamentos, atraso no crescimento e condenações nos frigoríficos. Este trabalho foi desenvolvido para determinar a frequência e descrever os achados histopatológicos das doenças de pele em suínos nas diferentes faixas etárias, através de um estudo retrospectivo no período de 2006 a 2018. Foram analisados 154 casos conclusivos incluindo as doenças restritas a pele (dermatites alérgicas, epidermite exsudativa, dermatite vesicular, pitiríase rósea, varíola suína, cisto folicular, papiloma e hemangioma escrotal) e as secundárias a doenças sistêmicas (erisipela, síndrome dermatite nefropatia suína (SDNS), septicemia bacteriana e hemorragias múltiplas de causa não determinada). Estas foram classificadas em bacterianas (46,1%), virais (26,6%), alérgicas (12,3%), neoplásicas (1,3%) e outras (13,6%). A erisipela suína foi a enfermidade mais diagnosticada (47/154), seguida por SDNS (23/154), dermatite alérgica (19/154) e epidermite exsudativa (15/154). Observamos ainda dermatite vesicular (9/154), pitiríase rósea (9/154), septicemia bacteriana com manifestações cutâneas (9/154), varíola suína (9/154) e hemorragias múltiplas de causa não determinada (7/154). Em menor número, cisto folicular (3/154), hiperqueratose sem causa definida (2/154), papiloma (1/154) e hemangioma escrotal (1/154). Dos casos conclusivos, a idade foi informada em 138 casos, sendo a maior frequência das lesões de pele observadas na linha de inspeção, durante o abate (56/138).

Obstructive urolithiasis is a disease characterized by the presence of uroliths in the urinary tract, with consequent obstruction of excretion pathways. This paper described the epidemiological and clinical-pathological findings of 22 outbreaks of urolithiasis in growing-finishing pigs in Southern Brazil. All affected pigs were male and clinical presentation consisted of lethargy, dysuria, rectal prolapse, abdominal distention, peripheral cyanosis and reluctance to move. Clinical progression course ranged from 12 hours to one week, and the lethality rate was 100%. Gross changes were characterized by urinary bladder rupture associated with marked amount of yellowish liquid with ammoniacal odor (urine) in the abdominal cavity (uroperitoneum), as well as mild fibrin deposition on the surface of abdominal organs and hydronephrosis. Urinary uroliths ranging from 0.3 to 1cm in diameter were often observed obstructing the lumen of the penile urethra and sometimes those were free in the abdominal cavity. Histopathological findings included diffuse and marked urinary bladder edema and hemorrhage associated with inflammatory infiltrate of lymphocytes, plasma cells, and macrophages. Diffuse and marked necrosis of the mucosal epithelium was observed in the penile urethra. Intense fibrin deposition and inflammatory infiltrate of neutrophils were noted in the peritoneum, as well as in the serosa of the organs in the abdominal cavity. Uroliths were submitted to the method of qualitative determination of the mineral components, and were compatible with calcium carbonate and magnesium ammonium phosphate. Growing pigs ration analysis revealed low levels of calcium in relation to phosphorus, resulting in a Ca:P ratio of approximately 0.35:1. Histological findings and mineral analysis suggest that outbreaks of urolithiasis were related to a nutritional imbalance in the proportions of dietary calcium and phosphorus. The main cause of mortality was related to dehydration and uroperitoneum. RESUMO: Urolitíase obstrutiva é uma enfermidade caracterizada pela presença de urólitos no trato urinário, com consequente obstrução das vias de excreção. Este artigo descreve os achados epidemiológicos e clínico-patológicos de 22 surtos de urolitíase em suínos de crescimento e terminação no Sul do Brasil. Os suínos afetados eram machos e clinicamente apresentavam letargia, disúria, prolapso retal, abaulamento do abdômen, extremidades cianóticas e relutância em movimentar-se. A duração dos sinais clínicos variou de 12 horas a uma semana, e a letalidade foi de 100%. As alterações macroscópicas caracterizaram-se por ruptura da bexiga com acentuada quantidade de líquido de coloração amarelada e odor amoniacal (urina) livre na cavidade abdominal (uroperitônio), além de discreta deposição de fibrina sobre os órgãos e hidronefrose. Frequentemente obstruindo o lúmen da uretra peniana e por vezes livre na cavidade abdominal, era possível observar urólitos urinários que variavam de 0,3 a 1cm de diâmetro. Os achados histopatológicos incluíram edema e hemorragia difusos e acentuados na bexiga, associado a infiltrado inflamatório predominante de linfócitos, plasmócitos e macrófagos. Na uretra peniana havia necrose difusa e acentuada do epitélio da mucosa. No peritônio e nas serosas dos órgãos da cavidade abdominal havia intensa deposição de fibrina e infiltrado neutrofílico. Os urólitos foram submetidos ao método de determinação qualitativa dos componentes minerais, os quais foram compatíveis com carbonato de cálcio e fosfato de amônio magnesiano. A análise da ração de crescimento revelou baixos níveis de cálcio, em relação ao fósforo, perfazendo uma relação Ca:P de aproximadamente 0,35:1. Os achados histológicos e as dosagens minerais sugerem que os surtos de urolitíase foram relacionados a um desequilíbrio nutricional nas proporções de cálcio e fósforo dietético. A principal causa da morte dos suínos foi relacionada à desidratação e ao uroperitônio.

Naegleria fowleri é uma ameba de vida livre, comumente encontrada no meio ambiente, principalmente em água doce e no solo. Este protozoário é ocasionalmente associado a casos fatais de doença do sistema nervoso central em seres humanos e espécies animais. No presente trabalho, um caso de meningoencefalite por Naegleria fowleri em um bovino na região sul do Brasil é descrito. Uma vaca Angus, de quatro anos de idade apresentou histórico clínico caracterizado inicialmente por sinais neurológicos leves que progrediram para movimentos de pedalagem, opistótono e decúbito lateral após cinco dias. Este animal era mantido em um piquete em resteva de arroz irrigado. Macroscopicamente, as principais lesões foram caracterizadas por múltiplas áreas de malacia no bulbo olfatório direito, lobos piriformes, hipocampo, córtex do lobo frontal e no fórnix, bem como acentuado espessamento das leptomeninges do mesencéfalo e rombencéfalo. Microscopicamente, meningoencefalite necrossupurativa e hemorrágica associada à grande número de trofozoítos amebianos foram observadas. Estes foram confirmados como Naegleria spp. através de imuno-histoquímica. Baseado na forte congruência apresentada entre os dados histopatológicos provenientes de casos conhecidos publicados na literatura, uma provável associação com Naegleria fowleri foi estabelecida. O presente trabalho trata-se do segundo relato de meningoencefalite associada à Naegleria fowleri em bovinos na América do Sul e o primeiro na região sul do Brasil. Naegleria fowleri is a free-living amoeba commonly found in the environment, mainly in fresh water and soil. This protozoon is occasionally involved in cases of fatal central nervous system disease in humans and other animal species. We describe here a case of meningoencephalitis due to Naegleria fowleri in cattle, in southern Brazil. A four year old Angus cow presented a clinical history of initial mild neurological signs that progressed to paddling movements, opisthotonus and lateral recumbency after five days. This animal had been kept in an irrigated rice stubble paddock. Grossly, the main lesions consisted of multiple areas of malacia in the right olfactory bulb, piriform lobes, hippocampus, frontal lobe cortex and fornix, along with severe thickening of the mesencephalon and rhombencephalon leptomeninges. Microscopically, severe multifocal necrosuppurative and hemorrhagic meningoencephalitis associated with a large quantity of amoebic trophozoites was present. The latter were confirmed to be Naegleria spp., through immunohistochemistry. Based on the strong congruence with the histopathological data of known cases reported in the literature, a probable association with Naegleria fowleri was established. To our knowledge, this is only the second report of Naegleria fowleri-associated meningoencephalitis in cattle in South America, and it is the first in southern Brazil.

Rhabdomyoma is a rare neoplasm of striated muscle that occurs predominantly in the myocardium. In animals, cardiac rhabdomyoma are observed as incidental lesions in slaughter pigs and have been rarely described in other species, such as cattle, dogs, and deer. This report describes a case of cardiac rhabdomyoma in a male pig at slaughter age that died suddenly in the pre-slaughter period. At necropsy, multiple nodules were observed in the right and left ventricular walls and the interventricular septum. Histopathological examination showed neoplastic proliferation composed of polyhedral cells, with vacuolated cytoplasm that sometimes presented a “spider cell” appearance. Histochemical staining with Schiff’s periodic acid revealed glycogen granules in the cytoplasm of neoplastic cells. The neoplastic cells were positive for desmin, neuron-specific enolase, atrial natriuretic peptide, and vimentin by immunohistochemistry, to varying degrees. The anatomopathological and immunohistochemical findings observed in this case confirmed the diagnosis of cardiac rhabdomyoma, possibly originating from the Purkinje fibers. RESUMO: Rabdomioma é um neoplasma raro de músculo estriado que ocorre predominantemente no miocárdio. Em animais rabdomiomas cardíacos são observados como lesões incidentais em suínos de abate, raramente descrito em outras espécies como bovinos, cães e cervos. Neste relato descreve-se um caso de rabdomioma cardíaco em um suíno, macho, em idade de abate que morreu subitamente no período pré-abate. Na necropsia visualizou-se múltiplos nódulos nas paredes ventriculares direita e esquerda, e septo interventricular. O exame histopatológico mostrou proliferação neoplásica composta por células poliédricas, com citoplasma vacuolizado que por vezes apresentavam aspecto de “célula de aranha”. Na coloração histoquímica de ácido periódico de Schiff evidenciaram-se grânulos de glicogênio no citoplasma das células neoplásicas. As células neoplásicas foram imunorreativas na imuno-histoquímica para desmina, enolase neurônio específica, peptídeo natriurético atrial e vimentina em diferentes graus. Os achados anatomopatológicos e imuno-histoquímicos observados neste caso confirmam o diagnóstico de rabdomioma cardíaco, possivelmente com origem das fibras de Purkinje.

Sida carpinifolia é uma planta responsável por intoxicar várias espécies animais. Este artigo descreve hipomielinogênese em fetos e neonatos de bovinos que consumiram S. carpinifolia. Os neonatos manifestaram ataxia e tremores musculares. Dois neonatos e quatro fetos bovinos foram necropsiados e não havia alterações macroscópicas significativas. Os achados histopatológicos incluíram vacuolização de células acinares do pâncreas, células foliculares da tireoide, hepatócitos, células renais tubulares e neurônios nos fetos. Nos neonatos havia vacuolização na substância branca do lobo frontal telencefálico, além de esferoides axonais no encéfalo dos fetos e dos recém-nascidos. A avaliação lectino-histoquímica demonstrou marcação para as lectinas Con-A, WGA e s-WGA. A coloração de Luxol Fast Blue revelou diminuição acentuada da mielina no telencéfalo de todos os fetos e diminuição moderada nos neonatos. Os achados histológicos e lectina-histoquímicos indicam que o consumo de S. carpinifolia por fêmeas bovinas gestantes pode causar hipomielinogênese em fetos e neonatos. Sida carpinifolia is a plant responsible for poisoning several species of animals. This paper describes Hypomyelinogenesis in fetuses and neonates of cattle that consumed S. carpinifolia. Neonates manifested ataxia and muscle tremors. Two bovine newborns and four fetuses were necropsied and showed no significant gross changes. Histopathologic findings included vacuolation of pancreatic acinar cells, thyroid follicular cells, hepatocytes, cells of renal tubules and neurons of the fetus and the white matter of the telencephalic frontal lobe of the neonates and also revealed axonal spheroids in the brain of the fetuses and neonates. The lectin-histochemical evaluation shoved staining for the lectins Con-A, WGA and s-WGA. The Luxol Fast Blue staining revealed a marked decrease of myelin in the brain of all the fetuses and a moderate decrease in the neonates. Histologic and lectin-histochemic findings indicate that the consumption of S. carpinifolia by pregnant bovine females can cause hypomyelinogenesis in fetuses and neonates.

Enterotoxigenic Escherichia coli (ETEC) causes diarrhea in pigs, referred to as colibacillosis. The aim of this study was to optimize multiplex polymerase chain reaction (PCR) and immunohistochemistry (IHC) analyses of paraffin-embedded material to detect pathogenic E. coli strains causing colibacillosis in pigs. Multiplex PCR was optimized for fimbriae (F18, F4, F6, F5, and F41) and toxins (types A and B heat-stable toxins [STaP and STb], heat-labile toxin [LT], and type 2 Shiga toxin [STx2e]), and IHC was optimized for an anti-E. coli polyclonal antibody. Samples (132) from pigs received between 2006 and 2014 with clinical and histopathological diagnoses of colibacillosis were analyzed. E. coli was detected by IHC in 78.7%, and at least one virulence factor gene was detected in 71.2%. Pathogenic strains of ETEC with at least one fimbria and one toxin were detected in 40% of the samples in multiplex PCR. The most frequent virulence types were F18-STaP (7.5%), F18-STaP-STb (5.7%), and F4-STaP (3.8%). A statistically significant association was noted between virulence factors F4, F18, STaP, and STb and positive immunostaining results. Colibacillosis diagnosis through multiplex PCR and IHC of paraffin-embedded tissues is a practical approach, as samples can be fixed and stored for long periods before analysis.

Monosodium methanearsonate (MSMA) is an organic form of arsenic present in the formulations of some herbicides. Accidental ingestion of pasture contaminated with arsenic may lead to toxicosis in cattle. Almost 200 head of cattle maintained in an area sprayed with MSMA presented with intense diarrhea and dehydration after grazing. Subsequently, 16 of these animals died. Toxic levels of arsenic (>1.5μg/g) were detected in the kidney, liver, urine, and skeletal muscle of 6 animals. At gross inspection were observed multifocal to coalescent ulcers in the mucosa from on the forestomachs associated with hemorrhagic areas and marked wall edema. Microscopic examination mainly showed fibrinoid necrosis of vessels with multifocal thrombosis associated with ischemic infarction that were characterized by large transmural necrotic areas in the forestomachs. The clinical and pathological changes interestingly showed that this form of arsenic although considered less toxic, has caused severe vascular injury in forestomachs of cattle. RESUMO: Metano-arseniato ácido monossódico (MSMA) é uma forma orgânica de arsênio, presente nas formulações de alguns herbicidas. A ingestão acidental de pasto contaminado por arsênio pode levar a toxicose em bovinos. Aproximadamente 200 bovinos que estavam em uma pastagem pulverizada com MSMA manifestaram intensa diarreia e desidratação após o pastejo. Subsequentemente, 16 animais morreram. Níveis tóxicos de arsênio (>1.5μg/g) foram detectados no rim, fígado, urina e músculo esquelético de 6 animais. A inspeção macroscópica revelou úlceras multifocais a coalescentes na mucosa de pré-estômagos, adjacentes a focos de hemorragia e intenso edema de parede. A avaliação microscópica revelou, predominantemente, necrose fibrinoide de vasos com trombose multifocal associada a infarto, caracterizado por grandes áreas de necrose transmural em pré-estômagos. As alterações clínicas e patológicas, interessantemente, demonstraram que esta forma de arsênio, apesar de ser considerada menos tóxica, causou severa injúria vascular em pré-estômagos de bovinos.

RESUMO: Realizou-se um estudo retrospectivo com o objetivo de determinar os tipos de neoplasmas em bovinos e a sua frequência. Foram analisados os casos de necropsias e biopsias de bovinos com diagnóstico de neoplasia, submetidos ao Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS), entre janeiro de 2005 e dezembro de 2014. De um total de 4.188 exames realizados em bovinos, 154 foram diagnosticados como neoplasmas. Destes, 100 casos foram a causa da morte, 41 foram achados de frigorífico e 13 casos eram biopsias de cirurgias realizadas por veterinários de campo. Os neoplasmas ocorreram com maior frequência em bovinos adultos (96/154), fêmeas (125/154) e a raça mais acometida foi a Holandesa (79/154). Os neoplasmas mais frequentes foram linfoma (73/154), carcinoma de células escamosas (28/154), papiloma (9/154), melanoma (6/154) e feocromocitoma (6/154). Os sistemas mais acometidos foram o hemopoiético (75/154) e tegumentar (25/154). Conclui-se que o linfoma e o carcinoma de células escamosas são os neoplasmas mais frequentes em bovinos diagnosticados no SPV-UFRGS, Brasil. ABSTRACT: A retrospective study has been conducted with the objective of determining the types of bovine neoplasms and their frequency. Necropsy and biopsy cases with diagnosis of neoplasm in cattle submitted to the Setor de Patologia Veterinária of Universidade Federal do Rio Grande do Sul (SPV-UFRGS) from January 2005 to December 2014 were analyzed. A total of 4,188 exams were performed in cattle, and 154 were diagnosed as neoplasm. From these 154 occurrences, 100 cases of neoplasm were the cause of death, 41 were collected from cattle in slaughter house and 13 were biopsies sent by field veterinarians. Neoplasms occurred more frequently in adult cattle (96/154), females (125/154) and the most affected breed was Holstein-Friesian (79/154). The most common neoplasms were lymphoma (73/154), squamous cell carcinoma (28/154), papilloma (9/154), melanoma (6/154) and pheochromocytoma (6/154). The most affected systems were hemopoietic (75/154) and integumentary (25/154). We concluded that lymphoma and squamous cell carcinoma are the most common neoplasms in cattle diagnosed in SPV-UFRGS, Brazil.

Reproductive failure in swine herds is often difficult to diagnose and is important to swine production. The present study aims to identify the potential risk factors (infectious/noninfectious) for stillborn piglets in two commercial swine farms situated in midwestern region of Brazil. The potential risk factors were included in a multivariable logistic model, and the dependent variable was defined as the presence of at least one stillborn piglet in a given litter (yes or no). In the best fit model, two variables from the multivariable analysis, total litter size (p = 0.01), and average birth weight (p = 0.03) were significantly associated with the presence of stillborn piglets at the farms examined in this study. Porcine circovirus type 2 (PCV2) was detected in 29.1 % of the litters. Neither parvovirus (PPV) nor leptospirosis infections were identified in this study, suggesting that they have a minor impact on reproductive disease.

Background: Renal dysplasia, which has been reported in some dogs and human patients, refers to a developmental disorder of renal parenchyma due to imperfect inductive interaction between the mesonephric duct and the metanephric blastemal. In dogs, the characteristic histological findings on which diagnosis is based include (1) persistent metanephric ducts surrounded by primitive mesenchyme, (2) fetal or immature glomeruli, (3) fetal or immature tubules, and (4) anomalous presence of interstitial fibrous tissue. The aim of this study was to report the major pathological and immunohistochemical features of nine young dogs necropsied with renal dysplasia.Cases: The necropsy files from the Laboratório de Patologia Veterinária (LPV) of the Universidade Federal do Mato Grosso (UFMT) were reviewed between the years 2008 and 2013. Dogs diagnosed with chronic kidney failure and macroscopic and histopathological renal lesions consistent with renal dysplasia were selected. Kidney fragments in paraffin blocks were cut and stained with hematoxylin and eosin and by immunohistochemistry (IHC) using anti-vimentin and anti-cytokeratin monoclonal antibodies. The staining was considered positive for the presence of at least one renal cell marked with brown cytoplasmic staining clear and unambiguous. A total of 787 necropsies of dogs were performed. Of these, 64 had a clinical diagnosis of chronic renal failure of which 9 were classified as renal dysplasia. The age of the dogs ranged from 3 months to 2 years. Clinical signs were characterized by anorexia and non-regenerative anemia in 88.9%, vomiting 66.7%, dehydration 55.6%, uremia 55.6%, convulsion 33.4%, abdominal pain 22.3% and diarrhea in 11.2% of cases. At necropsy the main macroscopic changes in the kidneys were external surface with pale staining, in 6 of 9 dogs necropsied. Additionally, 5 dogs, cystic cavities of various sizes from 0.1 to 5 cm in diameter, diffusely distributed in the renal subcapsular surface and cutting were observed. Of the 64 dogs with diagnosis of chronic renal failure, 14.06% had dysplastic kidney changes, characterized by dilatation of Bowman’s space, glomerular and tubular atrophy, immature glomeruli and tubules, lymphocytic interstitial inflammation and fibrosis. In the dogs with renal dysplasia, it was observed that the tubular structures showed marked glomerular labeling for vimentin. Moreover, the kidneys of normal dogs showed weak or absent for marking tubes and glomerular structures for vimentin, and strong staining for cytokeratin in tubular cells, glomerular cells and collecting ducts.Discussion: Renal morphological damage observed in these nine dogs less than two years old, that contained degenerative and inflammatory changes, fibrosis and glomerular atrophy, but mostly immature glomeruli and tubules were associated with atypical renal dysplasia. This condition develops when the urethral diverticulum and metanephric blastoma not properly form in the embryonic stage, resulting in abnormal metanephric differentiation and formation of structures that do not recapitulate the normal nephrogenesis. Abnormal kidney function in young animals caused chronic renal failure resulting in death. The results of immunohistochemical observed in this study can complement the diagnosis of renal dysplasia. The morphological normality can be observed in the proportion of mesenchymal and epithelial tissue in the different structures of the kidney by staining with anti-cytokeratin and anti-vimentin. In the present study, there was moderate to strong labeling of vimentin in glomerular and tubular structures being dysplastic kidney would be expected to occur in normal dogs predominant staining with cytokeratin. Based on the clinic, pathological and immunohistochemical findings it is concluded that the animals developed renal dysplasia.

Bluetongue (BT) is a vector-borne viral disease caused by the Bluetongue virus (BTV), an Orbivirus from the Reoviridae family, affecting domestic and wild ruminants. BTV circulation in Brazil was first reported in 1978, and several serological surveys indicate that the virus is widespread, although with varied prevalence. In 2014, BT outbreaks affected sheep flocks in Rio Grande do Sul state, causing significant mortality (18.4%; 91/495) in BTV-infected sheep. In total, seven farms were monitored, and one or two sheep from each farm that died due to clinical signs of BT were necropsied. Apathy, pyrexia, anorexia, tachycardia, respiratory, and digestive disorders were noted. Additionally, an abortion was recorded in one of the monitored farms. The main gross lesions observed were pulmonary edema, anterior-ventral pulmonary consolidation, muscular necrosis in the esophagus and in the ventral serratus muscle, and hemorrhagic lesions in the heart. The blood and tissue samples were tested for BTV RNA detection by RT-qPCR targeting the segment 10. Positive samples were used for viral isolation. The isolated BTVs were typed by conventional RT-PCR targeting the segment 2 of the 26 BTV serotypes, followed by sequencing analysis. BTV-1, BTV-4 and BTV-17 were identified in the analyzed samples. Double or triple BTV co-infections with these serotypes were detected. We report the occurrence of BT outbreaks related to BTV-1, BTV-4 and BTV-17 infections and co-infections causing clinical signs in sheep flocks in Southern Brazil, with significant mortality and lethality rates.

Twenty-six cattle and 7 horses were diagnosed with rabies. Samples of brain and spinal cord were processed for hematoxylin and eosin staining and immunohistochemistry (IHC). In addition, refrigerated fragments of brain and spinal cord were tested by direct fluorescent antibody test and intracerebral inoculation in mice. Statistical analyses and Fisher exact test were performed by commercial software. Histologic lesions were observed in the spinal cord in all of the cattle and horses. Inflammatory lesions in horses were moderate at the thoracic, lumbar, and sacral levels, and marked at the lumbar enlargement level. Gitter cells were present in large numbers in the lumbar enlargement region. IHC staining intensity ranged from moderate to strong. Inflammatory lesions in cattle were moderate in all spinal cord sections, and gitter cells were present in small numbers. IHC staining intensity was strong in all spinal cord sections. Only 2 horses exhibited lesions in the brain, which were located mainly in the obex and cerebellum; different from that observed in cattle, which had lesions in 25 cases. Fisher exact test showed that the odds of detecting lesions caused by rabies in horses are 3.5 times higher when spinal cord sections are analyzed, as compared to analysis of brain samples alone.

Avaliou-se o efeito da suplementação de mananoligossacarídeo, ß-glucano e antibiótico em dietas de leitões machos castrados, durante a fase de creche (21 aos 54 dias de idade), sobre o desempenho, características morfo-histológicas da mucosa intestinal e ocorrência de diarreia. Foram utilizados 368 leitões de mesma linhagem, distribuídos em delineamento inteiramente ao acaso, com quatro tratamentos (1: 330g de mananoligossacarídeo t/ração (oriundos do núcleo), 2: 1.830g de mananoligossacarídeo t/ração (330g oriundos do núcleo + 1.550g da suplementação), 3: 330g de mananoligossacarídeo (oriundos do núcleo) + 500g de ß-glucano t/ração e 4: 330g de mananoligossacarídeo (oriundos do núcleo) + 250g de Colistina t/ração) e quatro repetições com 23 animais por unidade experimental. O desempenho foi avaliado pelo ganho de peso, consumo de ração e conversão alimentar. As características morfo-histológicas da mucosa intestinal estudadas foram altura de vilosidade, profundidade das criptas intestinais, perímetro de vilosidade e a relação altura de vilosidade:profundidade de cripta do duodeno, jejuno e íleo. A ocorrência de diarreia foi observada diariamente pela avaliação de escore fecal. A suplementação de mananoligossacarídeo, β-glucano e antibiótico na dieta de leitões machos castrados, na fase de creche, não influenciaram o desempenho e a ocorrência de diarreia. Maior altura de vilosidade e maior profundidade de criptas no duodeno e íleo foram verificadas nos animais suplementados com ß-glucano. No jejuno foi observado maior perímetro de vilosidade nos animais suplementados com ß-glucano e nos animais que não receberam suplemento adicional na dieta. The aim of this study was to evaluate the effect of supplementation with mannan oligosaccharides, ß-glucan and antibiotic in diets for castrated male piglets during the nursery phase (21 to 54 days of age) on performance, morpho-histological characteristics of the intestinal mucosa and occurrence of diarrhea. A total of 368 piglets of the same strain, distributed in a completely randomized design with four treatments (1- 330 g mannan oligosaccharides/t of diet (derived of nucleus); 2 - 1,830 g mannan oligosaccharides/t of diet (330g derived of nucleus + 1550g of supplementation); 3 - 330g mannan oligosaccharides (derived of nucleus) + 500g ß-glucan/t of diet; and 4 - 330g mannan oligosaccharides (derived of nucleus) + 250g colistin/t of diet) and four replications with 23 animals per experimental unit. Performance was assessed through weight gain, feed intake and feed conversion. The morpho-histological characteristics of the intestinal mucosa studied were villus height, intestinal crypt depth, villus circumference and villus height:crypt depth of duodenum, jejunum and ileum ratio. The occurrence of diarrhea was observed daily by the evaluation of fecal score. Supplementation of mannan oligosaccharides, ß-glucan and antibiotic in the diet of castrated male piglets in the nursery phase did not affect performance and occurrence of diarrhea. Greater villus height and crypt depth in the duodenum and ileum were verified in the animals supplemented with ß-glucan. In the jejunum, greater villus circumference was observed in the animals supplemented with ß-glucan and in the animals that did not receive additional supplemented diet.

Made available in DSpace on 2015-03-19T16:20:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-01Bitstream added on 2015-03-19T16:29:27Z : No. of bitstreams: 1 S0103-84782015000200284.pdf: 768642 bytes, checksum: aed0172457c4e3c71cda430fa00a7e35 (MD5) Item merged in doublecheck by Felipe Arakaki (arakaki@reitoria.unesp.br) on 2015-12-14T11:31:45Z Item was identical to item(s): 116937, 113382 at handle(s): http://hdl.handle.net/11449/117866, http://hdl.handle.net/11449/114274 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Colangiocarcinomas são neoplasias originárias do epitélio do ducto biliar. O presente caso descreve os achados macroscópicos, microscópicos e imuno-histoquímicos de um colangiocarcinoma em uma ema fêmea (Rhea americana araneipes). No fígado, massas irregulares, firmes, multifocais, de coloração amarelo-esbranquiçada, medindo de 0,4 a 6cm de diâmetro foram observadas em ambos os lobos. Ao corte, múltiplos nódulos firmes preenchidos por tecido conjuntivo foram observados. Microscopicamente, a neoplasia era composta de células pequenas, irregulares, semelhantes às células do epitélio biliar, que formavam estruturas glandulares. A imuno-histoquímica foi positiva para citoqueratina e negativa para vimentina. Este trabalho constitui o primeiro relato de uma neoplasia maligna fatal em uma ema. Cholangiocarcinomas are neoplasms that originate from the bile duct epithelium. The present case described a cholangiocarcinoma in an adult female American Rhea (Rhea Americana araneipes) by means of gross, histopathology and immunohistochemistry. Irregular, firm, multifocal, yellow-white masses, measuring from 0.4 to 6cm in diameter were observed in both liver lobes. At the cut surface, multiple firm nodules filled with connective tissue were present. Microscopically, the neoplasia was composed of small, irregular, gland-like structures of neoplastic cells surrounded by connective tissue. The cells resembled epithelial cells of the hepatic biliary ducts. Neoplastic cells were positive for cytokeratin and negative for vimentin. This is the first report of a malignant fatal neoplasia in an American Rhea. Universidade Estadual Paulista Departamento de Clínica Cirurgia e Reprodução Animal Universidade Federal do Mato Grosso Departamento de Clínica Médica Universidade Federal do Rio Grande do Sul Laboratório de Patologia Veterinária Universidade Estadual Paulista Departamento de Clínica Cirurgia e Reprodução Animal FAPESP: 2013/08702-4

The objectives of this study were to (1) investigate the occurrence of hepatitis E virus (HEV) in pigs from large-scale and family-scale farms, (2) genetically characterize the strains isolated, and (3) study the pathogenesis of swine HEV infection via immunohistochemistry. A total of 50 pigs from 10 farms in Mato Grosso State, Brazil were divided according to type of production system into either large-scale farms (n = 5) or family-scale farms (n = 5). Samples of liver, gallbladder, small and large intestines, bile, and feces from the pigs were analyzed by nested PCR with primers targeting the ORF2 region of HEV and by immunohistochemistry. Of the eight HEV-positive samples from pigs of family-scale farms, phylogenetic analysis revealed that seven of the swine HEV isolates clustered with subtype 3b of genotype 3 and one isolate was categorized with subtype 3 f. The HEV antigen was detected mainly in the small intestine samples from family-scale farms, suggesting an early stage HEV infection. HEV was not detected in the samples of pigs from large-scale farms, reinforcing the need for additional studies to evaluate the risk of transmission of HEV to humans from pigs from family-scale farms in Mato Grosso State.

Conidiobolomycosis and pythiosis are important diseases of sheep in midwestern Brazil. Veterinary practitioners consider it difficult to differentiate between these diseases because they have similar clinical features. In this study, 186 sheep were subjected to necropsy examination over a 6-year period. Thirty (16.1%) cases of rhinitis in sheep that were caused by Conidiobolus lamprauges (n = 15) or Pythium insidiosum (n = 15) were investigated further. The lesions of C. lamprauges infection were mainly rhinopharyngeal (86.7%), localized to the ethmoidal region and associated with exophthalmos. The lesions appear as a white to yellow, firm mass that microscopically appears as a granulomatous inflammatory reaction with numerous giant cells. In contrast, P. insidiosum infection is associated with rhinofacial (93.3%) lesions that mainly involve the frontal region and hard palate and appear as an irregular, friable, yellow to red mass. Microscopically, pythiosis presents as diffuse necrotizing eosinophilic rhinitis. Immunohistochemistry using polyclonal antisera raised specifically against the two organisms was used to confirm the identity of the infectious agent in each disease. This study reports the first immunohistochemical diagnosis of conidiobolomycosis and the first description of a rhinopharyngeal lesion caused by P. insidiosum in sheep.

An outbreak of compressive myelopathy in cattle associated with the improper use of an oil vaccine is described. Neurological signs were observed in 25 out of 3,000 cattle after 60 days of being vaccinated against foot and mouth disease. The clinical picture was characterized by progressive paralysis of the hind limbs, difficulty in standing up, and sternal recumbency during the course of 2-5 months. A filling defect between the L1 and L3 vertebrae was seen through myelography performed in one of the affected animals. A yellow-gray, granular and irregular mass was observed in four necropsied animals involving the spinal nerve roots and epidural space of the lumbar (L1-L4) spinal cord; the mass was associated with a whitish oily fluid. This fluid was also found in association with necrosis of the longissimus dorsi muscle. Microscopic changes in the epidural space, nerve roots, and spinal musculature were similar and consisted of granulomas or pyogranulomas around circular unstained spaces (vacuoles). These spaces were located between areas of severe diffuse hyaline necrosis of muscle fibers and resembled the drops of oil present in the vaccine. Relatamos um surto de mielopatia compressiva lombar em bovinos associada à aplicação de vacina oleosa de forma inadequada. De um total de 3000 bovinos, 25 apresentaram distúrbios neurológicos aproximadamente 60 dias após terem sido vacinados contra a febre aftosa. O quadro clínico foi caracterizado por paralisia progressiva de membros posteriores, dificuldade para permanecer em estação e decúbito esternal com evolução de 2-5 meses. A mielografia realizada em um animal revelou defeito de enchimento na altura das vértebras L1 e L3. Quatro animais foram necropsiados e foi visualizado massa tecidual, granular e irregular, envolvendo as raízes nervosas medulares e espaço epidural da região lombar (L1-L4); esse material era associado com líquido brancacento e oleoso. Havia também áreas de necrose no músculo Longissimus dorsi com material similar ao do espaço epidural. Microscopicamente, as alterações observadas no espaço epidural, raízes nervosas medulares e na musculatura foram similares sendo caracterizadas pela formação de múltiplos granulomas ou piogranulomas envolvendo espaços (vacúolos) circulares não corados (aparentemente, o local antes ocupado por gotículas de óleo presente na vacina), além de necrose hialina severa difusa de fibras musculares.