Anderson Luís Seitz

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.

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.

Intoxicação experimental por Sida carpinifolia (Malvaceae) em ovinos

Seven sheep received dry crushed Sida carpinifolia L.f. One of them died at 18 and other at 53 days of the experiment. Four others were euthanatized and necropsied at 30, 45, 75 and 100 days. For one sheep the supply of S. carpinifolia was interrupted on the 80th day of the experiment, and 70 days later the animal was euthanized and necropsied. The minimal amount of the dry plant consumed was 11 g/kg and the maximum was 30 g/kg. The progression of clinical findings was similar in six animals with slight diarrhea at 20 days of experiment. Neurological signs were observed at 25 days and included ataxia with dysmetria, muscle tremors of the head, atypical postural reactions, frequent falls, sluggish of movements, difficulty in grazing and swallowing. These signs were enhanced when the animals were forced to walk. Four of the animals presented progressive emaciation. The sheep whose supply of the plant was interrupted recovered gradually, and 11 days after the animal returned to normal. During necropsy, only enlarged mesenteric lymph nodes were observed. The histological alterations were more significant in the central nervous system, with multiple and severe cytoplasmic distention and vacuolation which affects specially Purkinje cells of the cerebellum, neurons of cerebral cortex, thalamus, midbrain and the ventral horn of spinal cord. Axonal spheroids in the brain, more frequently in the granular layer of cerebellum were also observed. The cytoplasmic vacuolation was also found in pancreatic acinar cells, renal tubules, thyroid follicular epithelium, hepatocytes and macrophages of lymphoid organs. The ultrastructural lesions observed were cytoplasmic vacuolation, some surrounded by membranes in Purkinje cells of cerebellum and thyroid follicular cells. The sheep, which had S. carpinifolia withdrawn from its diet for 70 days, had no significant histological alterations.

Use of lectin histochemistry to diagnose Sida carpinifolia (Malvaceae) poisoning in sheep

by standard histological methods and stained with haematoxylin and eosin. Microscopically, there was distension and vacuolation of Purkinje cells in the cerebellum (Fig 1) and of neurons in the cerebral cortex, thalamus, mesencephalon and spinal cord. Cytoplasmic vacuolation was also present in the epithelium of the pancreatic acinus and renal tubules, follicular epithelium of the thyroid, in hepatocytes, and in macrophages of the lymphoid tissues. Axonal spheroids were observed in the brain and spinal cord, particularly in the granular layer of the cerebellum. Lectin histochemistry was conducted on formalin-fixed, paraffin-embedded sections of the cerebellum and pancreas. The lectins used were obtained commercially (E-Y Labs) and are listed in Table 1. After deparaffinisation, the sections were incubated in 0·3 per cent hydrogen peroxide (H2O2) in methanol for 30 minutes at room temperature, rinsed several times in 0·01M phosphate-buffered saline (PBS), pH 7·2, and treated with 0·1 per cent bovine serum albumin in PBS for 15 minutes. Subsequently, they were incubated with biotinylated lectins for one hour, followed by incubation with avidinbiotin-peroxidase complex (Vector Labs) for 45 minutes. The peroxidase was marked by incubation for four to 10 minutes with buffered Tris-HCl, 0·05M, pH 7·6 solution containing 0·02 per cent diaminobenzidine and 0·05 per cent H2O2.All the sections were counterstained with Mayer’s haematoxylin. Each lectin was used at a dilution of 30 μg/ml in PBS, except for Arachis hypogaea (Table 1), which was applied at 10 μg/ml. As controls for the lectin histochemical procedure, the lectins were omitted or blocked by incubating them with their blocking sugars (0·1 to 0·2 per cent in PBS) for one hour at room temperature before application to the sections (Leathem 1986). The results of the lectin-binding patterns of affected and control sheep are summarised in Table 2. The cytoplasm of

Intoxicação por Erythroxylum deciduum (Erythroxylaceae) em ovinos

The epidemiological, clinical and pathological aspects of natural poisoning caused by Erythroxylum deciduum fruits in sheep are reported. The outbreak occurred from January to March of 2004, in Lagoa Vermelha county, state of Rio Grande do Sul, Brazil. The poisoning was experimentally reproduced by oral administration of E. deciduum fruits to 5 sheep.Three of them developed neurological signs and died. Poisoning was caused with a single dose of 60g/kg or when the dosage was fractioned into at least 4 doses of 17 g/kg given every 12 hours. The main clinical signs in natural and experimentally poisoned sheep were ataxia, hyperexcitability and muscular tremors which where more pronounced when the animals were moved. At the final stage, dyspnea with abdominal breathing and cyanosis was observed. The most significant alterations found at necropsy were pronounced edema, lung congestion and presence of the fruits or seeds of E. deciduum in the ruminal content of all animals. Histologically, except edema and pulmonary congestion, there were no other significant changes observed.

Pathological findings in fetuses of goats and cattle poisoned by Sida carpinifolia (Malvaceae)

In Brazil, the consumption of Sida carpinifolia by livestock has been associated with neurological diseases linked to lysosomal storage disorders. This paper describes the pathological findings in two caprine fetuses from dams that were experimentally poisoned with S. carpinifolia. The goats were orally dosed with 10 and 13g/kg of a paste of green chopped S. carpinifolia for 30 days and were observed for an additional 15 days period after the last dosage with the plant; thereafter they were euthanized and necropsied. The dams showed only slight clinical signs. The study also includes the findings in one bovine fetus from a naturally S. carpinifolia poisoned cow which showed mild incoordination, generalized tremors, staggering, and frequent falls. The cow was euthanized and necropsied. While there were no significant histopathological changes in the goats, in the cow vacuolation of Purkinje neurons of the cerebellum, pancreatic acinar cells, and thyroid follicular cells were observed. The main microscopic changes observed in the caprine and bovine fetuses were vacuolation in the epithelium of renal tubules, thyroid follicular cells, and Purkinje neurons of the cerebellum. Transmission electron microscopy of sections from CNS of the cow and its fetus revealed vacuoles containing fine granular material surrounded by membrane. Lectin-histochemistry of CNS sections from goat fetuses marked lightly to sWGA lectins, WGA, and Con-A.