Neurological disease in cattle in southern Brazil associated with Bovine herpesvirus infection.

The occurrence of neurological disease in cattle caused by Bovine herpesvirus in 11 farms from southern Brazil between 1987 and 2007 is described. Twenty-two animals were necropsied. Major clinical signs included excessive salivation, nasal and ocular discharge, circling, recumbency, depression, incoordination, grinding of teeth, and paddling movements. Necropsy findings in 10 of 22 cattle included hyperemia and softening of the rostral portions of the telencephalic cortex, with flattening of gyri, and malacia. Cattle in 10 cases did not show any gross lesions. Histological examination in most cases revealed nonsuppurative and necrotizing meningoencephalitis with acute neuronal necrosis, edema, eosinophilic intranuclear inclusion bodies in astrocytes and neurons, and infiltration of gitter cells. No histologic lesions could be detected in 4 cases. The initial diagnosis was based upon the clinical, epidemiological, and pathological findings. The diagnosis was confirmed by virus isolation in cell culture followed by virus identification by a glycoprotein C-based polymerase chain reaction. Seven isolates were identified as Bovine herpesvirus 5, and 4 were identified as Bovine herpesvirus 1.

Surto de aflatoxicose em bezerros no Rio Grande do Sul / Outbreak of aflatoxicosis in calves in southern Brazil

Um surto de aflatoxicose crônica é relatado em bezerros de raça leiteira. Quarenta bezerros holandeses machos de quatro meses de idade e aproximadamente 100kg eram mantidos em gaiolas individuais de 1,5 x 1,5m e alimentados com uma ração constituída por feno de alfafa, milho quebrado e substituto de leite. Seis bezerros (15 por cento) morreram após apresentar uma doença caracterizada por mau desenvolvimento geral, diarreia, pelagem áspera, dor abdominal, tenesmo, prolapso de reto e bruxismo. Alguns bezerros "deitavam e rolavam" no chão da gaiola. A duração do curso clínico, segundo observado pelos proprietários, foi de 2-3 dias; muitos terneiros desse lote que não morreram permaneceram pouco desenvolvidos. Três bezerros foram necropsiados. Os achados de necropsia incluíam fígado firme e castanho-claro, marcados hidrotórax e ascite, e edema do mesentério, mesocólon e das dobras da mucosa do abomaso. Os principais achados histopatológicos estavam restritos ao fígado e consistiam de fibrose, moderada megalocitose, hiperplasia de ductos biliares e lesão veno-oclusiva. A procura por contaminação de Senecio spp. no feno de alfafa resultou negativa. A análise do milho do alimento dos bezerros por cromatografia de camada delgada revelou 5.136ppb de aflatoxina B1. O diagnóstico de aflatoxicose foi feito baseado nos sinais clínicos e patologia característicos, na ausência de Senecio spp. na alimentação dos terneiros e na presença de altos níveis de aflatoxina no milho da alimentação dos bezerros.

An outbreak of chronic aflatoxicosis is reported in dairy calves. Forty 4-month-old male Holstein calves of approximately 100kg were kept in individual cages of 1.5 x 1.5m and were fed a ration constituted by alfalfa hay, broken corn and milk substitute. Six calves (15 percent) died after presenting a disease characterized by general unthriftiness, diarrhea, rough hair coats, abdominal pain, prolapsed rectum, grinding of teeth, and lying down and rolling. The clinical course, as observed by the owners, was 2-3 days; however many calves in this lot that did not die, remained underdeveloped. Three calves were necropsied. Necropsy findings included firm, light tan livers and marked hydrothorax, ascites and edema of the mesentery, mesocolon and of the mucosal folds of the abomasum. Main histopathological changes were restricted to the liver and consisted of fibrosis, moderate megalocytosis, biliary duct hyperplasia and veno-occlusive disease. The search for Senecio spp. contamination in the alfalfa hay resulted negative. The analysis by thin layer chromatography of the corn fed to calves revealed 5,136 ppb of aflatoxin B1. A diagnosis of aflatoxicosis was made based on the characteristic clinical signs and pathology, on the absence of Senecio spp. in the food and on the presence of high levels of aflatoxin in the corn fed to the calves.

Epidemiologia, sinais clínicos e distribuição das lesões encefálicas em bovinos afetados por meningoencefalite por herpesvírus bovino-5 / Epidemiology, clinical signs and distribution of the encephalic lesions in cattle affected by meningoencephalitis caused by bovine herpesvirus-5

São descritos sete surtos e um caso isolado de meningoencefalite por herpesvírus bovino-5 (BoHV-5) em bovinos no Rio Grande do Sul entre 2002 e 2004. Foram afetados bovinos de 1-18 meses, de diversas raças e ambos os sexos. A maior freqüência foi observada em bovinos recém-desmamados e submetidos a outros fatores de estresse. Nesses surtos, de uma população total sob risco de 1.359 bovinos, 54 foram afetados, quatro se recuperaram e 50 morreram espontaneamente ou foram submetidos à eutanásia quando moribundos. Os índices gerais de morbidade, mortalidade e letalidade foram, respectivamente, de 3,97 por cento, 3,67 por cento e 92,59 por cento. A evolução clínica variou de 3-10 dias e os sinais eram caracterizados por depressão, corrimento nasal ou ocular, ranger de dentes, andar em círculos, cegueira, febre, nistagmo, tremores, anorexia, disfagia, sialorréia, incoordenação, pressão da cabeça contra objetos, pêlos arrepiados, taquicardia, taquipnéia, dor abdominal, melena, quedas, decúbito, opistótono, convulsões e movimentos de pedalagem. Dezenove bezerros foram necropsiados. Achados de necropsia foram caracterizados por hiperemia das leptomeninges, tumefação das porções rostrais do telencéfalo, com achatamento das circunvoluções dos lobos frontais; nessas áreas havia focos marrom-amarelados e amolecidos (malacia). Nos casos de evolução clínica mais longa era observada acentuada tumefação, amolecimento e extensas áreas de hemorragia nos lobos frontais telencefálicos. Microscopicamente, todos os bovinos afetados apresentaram meningoencefalite não-supurativa e necrosante, que variou quanto à localização e intensidade nos 19 casos examinados e nas seções de encéfalo de um mesmo caso.

Seven outbreaks and an isolated case of meningoencephalitis caused by bovine herpesvirus-5 (BoHV-5) in cattle in Rio Grande do Sul, Brazil, occurring in 2002-2004, are described. From a total population at risk of 1,359 cattle, 54 1-18-month-old calves from both sexes and several breeds were affected and 50 died spontaneously or were euthanatized while moribund. The highest frequency of cases was in recently weaned calves or calves submitted to other stressing factors. General rates of morbidity, mortality and lethality were respectively 3.97, 3.67 and 92.59. Clinical courses varied from 3-10 days and included depression, nasal and ocular discharge, grinding of teeth, circling, blindness, fever, nistagmus, trembling, anorexia, dysphagia, drooling, incoordination, head pressing, rough hair coat, tachycardia, tachypnea, abdominal pain, melena, falls, recumbency, opisthotonus, convulsions and paddling. Nineteen calves were necropsied. Necropsy findings were characterized by hyperemia of leptomeninges, swollen rostral portions of the telencephalon, and flattening of frontal lobes gyri; frequently in these frontal areas there were segmental brown-yellow discoloration and softening (malacia) of the cortex. In cases with more protracted clinical courses there were extensive swelling, softening and hemorrhaging of the telencephalic frontal lobes. Microscopically, all affected cattle had a necrotizing non-suppurative meningoencephalitis with variable distribution among the 19 cases and among the various telencephalic regions of the same case. The severity of these changes were more marked, in decreasing order of intensity, in the telencephalic frontal cortex, basal ganglia (nuclei), thalamus, brain stem, parietal telencephalic cortex, occipital telencephalic cortex and cerebellum. Perivascular inflammatory infiltrate consisted predominantly of lymphocytes, plasm cells, and less frequently of neutrophils. Additional microscopic findings included variable...