Edson Moleta Colodel

MENINGOENCEFALITE NECROSANTE EM BOVINOS CAUSADA POR HERPESVÍRUS BOVINO NO ESTADO DE MATO GROSSO, BRASIL

The epidemiological, clinical, pathological and microbiological aspects of 13 cases of necrotizing meningo-encephalitis associated to bovine herpesvirus are described. The disease is described in 12 cattle herds from March 1999 to August 2000 at 11 counties of the State of Mato Grosso, Brazil. The outbreaks were described in cattle raised on farms in which, mostly Zebu breeds were involved. The average age of the cattle affected was 24 months, ranging from two to 72 months old. Neurological manifestations were the main clinical signs noticed. The animals were separated from the herd. The animals showed profuse salivation, serous nasal and ocular discharge, profound depression, incoordination, walking or running in circles, blindness, diminution of tongue tonus, trembling and opistotonus. Most of the cases had no macroscopic alterations. Some cases had diffuse encephalic congestion, multifocal submeningeal hemorragics, flattened cerebral circumvolutions and focal discoloration of the cortex. The main microscopic lesions in the 12 cases were necrotizing meningo-encephalitis with eosinophilic intranuclear inclusion bodies in astrocytes, and cortical malacia. Virus was isolated from three cases submitted from a total of seven examined. One of the cases with virus isolation at the histophatology examination yielded a diagnosis of polioencephalomalacia.

Granulomatous encephalitis in a neurologically impaired goat kid associated with degeneration of Neospora caninum tissue cysts.

Congenital Neospora caninum infection was diagnosed in a Saanen goat from a farm in southern Brazil. The kid was unable to nurse and had difficulty rising, ataxia, and opistothotonos. The neurologic signs became more severe 3 days after birth, when it was euthanized. No gross lesions were observed at necropsy. Multifocal infiltrates primarily of mononuclear cells, nodular microgliosis, and perivascular cuffs of lymphocytes, plasma cells, and few neutrophils were observed in the brain, mostly in the cortex and adjacent to ventricles. Rare multinucleate giant cells were observed adjacent to inflammatory foci. Several tissue cysts with a thick wall that reacted strongly with polyclonal antiserum to N. caninum were in the cerebral cortex and medulla oblongata. Lesions were also present in heart, lungs, and liver, but N. caninum tachyzoites were not found. Distinguishing features in this goat kid included neurologic impairment resulting from congenital infection with N. caninum and the presence of granulomatous inflammation with rare giant cells associated with degeneration of tissue cysts.

Study of experimentally induced lesions in sheep by grazing Brachiaria decumbens.

A histologic and ultrastructural study of the alterations found in the lymph nodes and livers of nine sheep with experimental cholangiohepatopathy by grazing on Brachiaria decumbens has been performed. Sheep were euthanized in three groups, on the 77th, 89th, and 150th days of the experimental feeding. The main gross lesions were whitish spots of multifocal distribution scattered throughout the hepatic parenchyma from all B. decumbens-grazed animals and whitish foci surrounded by reddened halos in the mesenteric and hepatic lymph nodes of sheep necropsied on the 150th. The principal histologic findings included hepatocellular cloudy swelling, marked multifocal cholangitis in the portal triads with bile duct proliferation and infiltration of macrophages and lymphocytes. Crystals were observed within bile ducts and surrounded by macrophages. Ultrastructurally, there were criytaloid structures within the macrophages and hepatocytes, which also presented hyperplasia of smooth endoplasmic reticulum. These findings suggest that hepatocytes were the initial target of the toxic effects, which depending on the degree of severity developed would cause both, subsequent cholangiopathy or occasional photosensitization. Additionally, the developmental stages of the hepatic lesions observed in this study have been presented.

Aspectos clínicos e patológicos da intoxicação por Sida carpinifolia (Malvaceae) em caprinos no Rio Grande do Sul

This report includes the clinical and pathological studies of a lysosomal storage disease which spontaneously occurred in three flocs of goats e after consumption of Sida carpinifolia, the predominant plant in the paddocks where the animals were grazing. In the outbreaks a total of 25 out of 51 animals were affected. Post-mortem examination was performed on 11 goats. The disease was experimentally induced by dosing goats with Sida carpinifolia. The plant was administered in natura or dried to 3 animals. No clinical or pathological changes were observed in one goat dosed with Sida rhombifolia ad libidum during 40 days. Clinical signs of the poisoning were ataxia, hypermetria, muscle tremors in the head and neck and disorders of deglutition. The clinical signs were exacerbated by movement. After the surviving animals had been moved to other pastures and stopped eating the plant, clinical signs were still observed during 24 months. At necropsy, no significant gross lesions were observed. Microscopic lesions included various degrees of vacuolization in the cytoplasm of neurons and glial cells. Similar lesions were observed in the acinar pancreatic cells, hepatocytes, proximal convoluted tubular cells, follicular epithelial cells of the thyroid gland and macrophages of lymph nodes. In the surviving animals, mild neuronal cytoplasmic vacuolization was observed, and few cells were eosinophilic and shrunken. In these cases neurons, especially Purkinje cells, had disappeared. Through the histochemical study of the cerebellar sections, the lysosomal storage disease was characterized as an alpha-mannosidosis. The vacuoles within the Purkinje cells strongly reacted with lectins of Concanavalia ensiformis, Triticum vulgaris and succinylated Triticum vulgaris. The pattern observed in this investigation is similar to those seen in other poisonings by swainsonine-containing plants.

Intoxicaçäo experimental pelos frutos de Xanthium cavanillesii (Asteraceae) em bovinos

Os frutos moidos de Xanthium cavanillesii Schouw, foram administrados por via oral, em doses unica ou repetidas, com intervalo semanal, a onze bovinos. Desses, quatro morreram. Doses unicas a partir de 5 g/kg foram letais para bovinos. Dose de 3 g/kg produziu sinais clinicos e recuperacao em um bovino. Repeticoes de 4 doses de 3 g/kg para um bovino e 2 doses de 5 g/kg para outro bovino nao foram toxicas. Foram constatadas hipoglicemia e elevacao dos niveis sericos de aspartato aminotransferase (AST) nos bovinos que apresentaram sinais clinicos da intoxicacao. Os primeiros sinais clinicos nos animais que morreram foram observados entre 6 e 12 horas apos a administracao dos frutos. A evolucao do quadro clinico variou entre 5h30min e 8 horas. O quadro clinico foi semelhante nestes animais sendo que os principais sinais clinicos foram anorexia, apatia, salivacao profusa e tremores musculares. Ocorreram tambem hipomotilidade e atonia ruminal, colicas abdominais, gemidos frequentes, ranger de dentes, sudorese generalizada e endoftalmia. As alteracoes de locomocao observadas foram incoordenacao motora, instabilidade do trem posterior, decubito permanente com movimentos de pedalagem, espasmos musculares e opistotono. As alteracoes respiratorias foram aumento da frequencia respiratoria, respiracao laboriosa com ruidos e momentos de apneia. Finalmente ocorria perda do reflexo palpebral, ausencia de reflexo pupilar e morte. No bovino que se recuperou, os primeiros sinais clinicos foram observados 18 horas apos a administracao e evoluiram num periodo de aproximadamente 72 horas. Neste bovino, atraves de biopsias hepaticas, observou-se necrose hepatica coagulativa centrolobular associada a congestao e hemorragias. Necrose hepatica coagulativa massiva foi observado por biopsias hepaticas em um bovino que morreu, a partir de 12 horas apos a administracao dos frutos, associada com alteracoes nos niveis sericos de glicose e AST. As principais lesoes encontradas na necropsia foram no figado e consistiam de aumento do padrao lobular na superficie capsular e de corte, distensao da vesicula biliar e edema moderado da parede da vesicula biliar. A principal alteracao microscopica era caracterizada por necrose coagulativa centrolobular ou massiva associada a congestao e hemorragia e alteracoes degenerativas nos hepatocitos circunjacentes.

Intoxicação espontânea pelos frutos de Xanthium cavanillesii (Asteraceae) em bovinos no Rio Grande do Sul

Two outbreaks of Xanthium cavanillesii poisoning in feedlot cattle in the counties of Casca and Cachoeira do Sul, Rio Grande do Sul, southern Brazil, are described. The disease occurred on two farms in late April and mid August 1996. On one farm, 17 heifers out of 310 cattle died. On the other, 11 out of 83 yearling calves died. Clinical signs included depression, anorexia, progressive dehydration, sunken eyes, tenesmus and slight rectal prolapse, muscle tremors, incoordination of gait, blindness, aggressivity and recumbency. Blindness was present in the terminal stages prior to death that occurred within 3 to 24 hours after the onset of the clinical signs. Necropsy findings included accentuation of the lobular pattern of the liver with pinpoint hemorrhages on capsular and cut surfaces; perirenal edema, hydropericardium, and translucent and gelatinous edema of the gall bladder wall, mesentery, abomasal ligaments and folds. The feces were scant, dry and formed balls coated by mucus and streaks of clotted blood. There were widespread petechiae, ecchymoses and suffusions. Burs of X. cavanillesii were found mixed with the solid and dried contents of the rumen and reticulum. The main histopathological findings were marked centrilobular coagulative hepatocellular necrosis associated with congestion and hemorrhages, surrounded or not by a narrow rim of markedly swollen and vesicular hepatocytes. The animals were being fed with whole or milled leftovers from soybean crops contaminated with large amounts of burs of X. cavanillesii. Deaths stopped after the feeding with the soybean leftovers was discountinued. The diagnosis was based on epidemiological data, clinical signs, necropsy findings, histological lesions and experimental reproduction of the toxicosis in cattle and sheep. The morphology and pathogenesis of the hepatic lesion and the clinical and pathological aspects of the toxicosis are discussed and compared with other reports of Xanthium spp poisoning and other acute hepatotoxicoses in cattle.

Neurological disorder in dairy cattle associated with consumption of beer residues contaminated with Aspergillus clavatus.

A neurological syndrome in dairy cattle associated with consumption of moldy beer residues is described. The disease occurred on 1 farm in late June 2001, during winter. Six heifers and 1 cow out of 45 cattle were affected during a 3-week period. The affected animals died spontaneously or were euthanized approximately 2–14 days after the onset of clinical signs. The clinical signs were characterized by flaccid paralysis and gait abnormalities. Clinical signs were more pronounced after exercise and included stiff and unsteady gait, knuckling at the fetlocks of the hind limbs, frequent falling, inability to rise, muscular tremors, especially of the head and the hindquarters, and drooling. Main necropsy findings included degenerative and necrotic changes of the larger medial muscle groups of the hindquarters, i.e., adductor, pectineus, quadriceps femoris, rectus femuris, sartorius, semimembranosus, semitendinosus, and vastus medialis, and of the fore-quarters, including pectoralis descendens, pectoralis ascendens, and transversus pectoralis. The main histologic findings consisted of degenerative and necrotic neuronal changes (chromatolysis) of varying severity and extent affecting selected nuclei of the brainstem and neurons of the ventral horns of the spinal cord. Similar microscopic lesions were observed in the neurons of the spinal cord of 1 experimental sheep force-fed for 35 days with 1 kg/day of the same batch of foodstuff that was originally fed to the cattle. Coarse white or gray lumps, interpreted as mycelia, were observed in the beer by-product. Aspergillus clavatus was the dominant fungus isolated. Deaths ceased after the consumption of beer residue was discontinued. Recovery from illness was observed in 1 animal. The diagnosis was based on epidemiological data, clinical signs, necropsy findings, histological lesions, dosing trial, and mycology. A similar condition caused by consumption of barley byproducts, sprouted wheat, corn sprouts, and beetroot screenings contaminated with A. clavatus has been reported in cattle and sheep worldwide.

Granulomatous rhinitis associated with Pythium insidiosum infection in sheep.

Pythium insidiosum is an aquatic organism classified in the kingdom Stramenopila, class Oomycetes ([De Cock and others 1987][1]). It is the aetiological agent of pythiosis in mammals; the occurrence of this disease is associated with contact between traumatic lesions in animals or human beings and

Intoxicação experimental por Trema micrantha (Ulmaceae) em caprinos

Green leaves of Trema micrantha were ground and mixed with water in a domestic blender and then administered by stomach tube to seven goats. One additional goat was fed ad libidum with the green leaves of T. micrantha. Clinical signs were observed in six goats that became ill 2 days after having been dosed with or fed the plant. There were five deaths, which occurred until 4 days after ingestion. Affected goats remained static during long periods and kept their heads low. Incoordination, rhythmical movements of the head, apathy, anorexia, and tenesmus were also noticed. Paddling movements and coma were seen in one goat. T. micrantha was toxic at dosages of 30 g/kg or higher. The most significant gross lesions were observed in the livers, which were yellowish, friable, and with pronounced lobular pattern. Their cut surfaces were reddened and depressed areas alternated with whitish ones. The liver of one goat was slightly but homogeneously reddened but did not show accentuated lobulation. Petechial haemorrhages in the region between the chest and scapula, in the epicardium, mediastinum and serosal membranes of the abdominal organs were also observed. The most important histologic finding was hepatic centrilobular coagulative necrosis, which was associated with congestion, haemorrhages and degenerative changes in the circumjacent hepatocytes. Additional microscopic lesions were found in the nervous system and included perineuronal and perivascular edema and swollen neurones, especially those of the frontal cortex.

Intoxicação espontânea por Baccharis coridifolia (Compositae) em ovinos

An outbreak of Baccharis coridifolia (Compositae) poisoning in sheep is reported, which occurred in November 2004 in the county of Caxias do Sul, Rio Grande do Sul (RS), southern Brazil. From a herd of 212 sheep, coming from a Baccharis coridifolia free area, in the county of Jaguarao, RS, 35 sheep died until 5 days after the arrival in the new area where the plant was found with abundance. The clinical signs began 8 hours after introduction of the animals into the new pasture and included apathy, anorexia, abdominal retraction or mild distension, weakness of hind limbs, dry feces, sternal ou lateral decumbency, struggling movements, coma and death. Clinical evolution was from 5 to 48 hours. Other sheep that were already before on the pasture were not affected. Main necropsy findings were in the gastrointestinal tube, with wall and serosal oedema, mainly in the reticulo-ruminal fold and of the abomasum, reddening and detachment of the mucosa of forestomachs, and intense hemorrhage in the submucosa. Histopathological findings were degeneration and necrosis of the epithelium of the forestomachs with polymorphonuclear infiltration associated with bacterial colonies, congestion, hemorrhage and oedema, and lymphoid tissue necrosis.