Navegando por Autor "RIVERO, Beatriz Riet Correa"

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Alterações histológicas em fígados e linfonodos de búfalos (Bubalus bubalis) mantidos em pastagens de Brachiaria spp.
(2010-09) RIVERO, Beatriz Riet Correa; CORREA, Franklin Riet; OLIVEIRA JÚNIOR, Carlos Alberto de; CERQUEIRA, Valíria Duarte; RIVERO, Gabriela Riet Correa
Infiltration by foamy macrophages and other lesions are reported in healthy cattle held in Brachiaria spp. pastures. With the objective to study histologic lesions in the liver and mesenteric lymph nodes in buffalo in the state of Pará, samples of liver and lymph nodes of 142 buffalo Murah and 15 Nelore cattle were studied histologically. The samples were collected in an slaughterhouse and divided into groups of animals according to their origin and period of grazing Brachiaria spp. pastures. Group (G) 1 consisted of 79 buffalo from Marajó Island, raised in native pastures free of Brachiaria spp.; G2 was composed of 17 buffalo kept since birth in Brachiaria brizantha pastures; G3 was composed of 29 buffalo purchased in Marajó Island and introduced in B. decumbens pastures where they stayed for nearly 12 months; G4 consists of 17 buffalo purchased in Marajó Island and introduced in B. brizantha pastures where they stayed for nearly 18 months. G5 was composed of 15 Nelore cattle grazing B. brizantha during one year period. To assess the degree of liver injury, grades following a scale of 0 to 4 were established according to the quantity and size of groups of foamy macrophages. In G1, from the Marajó Island, there were no significant histological changes in liver and lymph nodes. Foamy macrophages and other lesions were observed in liver and lymph nodes of all samples from G1, G2, G3, and G4. The animals from G2 and G4, which remained a longer period in Brachiaria spp., showed more pronounced infiltration of foamy macrophages (P<0.05) than the animals of G3. Other lesions observed in the livers of these three groups were swollen, vacuolated or necrotic hepatocytes, mainly in the centrolobular region, and thickening of the Glisson's capsule with vacuolization and necrosis of subcapsular hepatocytes. These lesions were more pronounced in areas where exists higer infiltration of foamy macrophages. In cattle from G5 smaller groups of foamy macrophages were observed in the lymph nodes and were absent in the liver. These results suggest that the hepatic lesions observed in buffalo are caused by ingestion of Brachiaria spp. The presence of severe lesions in buffalo without clinical signs, much more severe than those observed and reported previously in cattle, as well as the low frequency of Brachiaria poisoning in buffalo grazing in Brachiaria spp. pastures, suggest that buffalo are resilient to Brachiaria spp. poisoning. In each group, there was no association between the weight at slaughter and the degree of lesion. It is also suggested that the observation of severe lesions of the liver, similar to those observed in this experiment, in animal that died from other diseases, can lead to a wrong diagnosis of Brachiaria poisoning.
Acesso aberto (Open Access)
Avaliação lectino-histoquímica de fígado e linfonodo mesentérico de búfalos mantidos em pastagens de Brachiaria spp.
(Universidade Federal do Pará, 2016-09) MIRANDA, Ileana Costa; RIVERO, Gabriela Riet Correa; OLIVEIRA JÚNIOR, Carlos Alberto de; RIVERO, Beatriz Riet Correa; PEIXOTO, Paulo Fernando de Vargas; COSTA, Samay Zillmann Rocha; D'AVILA, Mariana Sequeira; CID, Gabriela de Carvalho; FRANÇA, Ticiana do Nascimento
Animals grazing Brachiaria spp. commonly present foamy macrophages isolated or grouped in the liver, and crystals within biliary ducts. The pathogenesis of formation and the nature of the material stored in these cells however are not completely known. Through lectin histochemistry evaluation, steroidal saponins (secondary glycosylated metabolites) have been identified in the crystals and within the cytoplasm of the foam cells, which are probably liable for damaging the liver, leading to accumulation of phylloerythrin. This study aims to standardize and characterize the use of lectin histochemistry to detect glycosylated metabolites in tissues of buffaloes kept on different Brachiaria spp. pastures in Brazil. Fragments of liver and mesenteric lymph node from 40 buffaloes were analyzed: 10 buffaloes that were kept in predominant pasture of B. decumbens for 12 months; 10 buffaloes that were kept in pasture with a predominance of B. brizantha for 18 months; 10 buffaloes that were kept on pasture of B. brizantha for about four years; and as a negative control, 10 buffaloes that were maintained on native pasture without Brachiaria spp. since birth. Fourteen lectins were tested (Con-A, SBA, WGA, DBA, UEA, RCA, PNA, GSL-I, PSA, LCA, PHA-E, PHA-L, SJA and SWGA), in a total of 1120 evaluated samples. Previous studies demonstrated that PNA showed great binding reactivity for foamy macrophages in cattle and sheep. In the present study, SWGA showed high specificity and marked binding reactivity for foamy macrophages; WGA, GSL, PHA-E and PHA-L showed moderate to marked reactivity, but low specificity for foamy macrophages. The other lectins had not relevant reactivity or specificity. Moreover there was no relevant reactivity difference between the collected samplesd from buffaloes that grazed B. decumbens for 12 months and Brachiaria brizantha for 18 months. However the decreased presence of foamy macrophages and its lectin histochemical binding in animals that fed on B. brizantha for a longer time, indicates that the buffaloes can pass through an adaptation process according to the plant intake time. Lectin histochemistry analysis can be used to characterize the material stored in foamy macrophages present in liver and mesenteric lymph node of buffaloes that graze on Brachiaria spp. pastures and helps to clarify the pathogenesis of these cells.
Acesso aberto (Open Access)
Brachiaria spp. poisoning of ruminants in Brazil
(2011-03) RIVERO, Beatriz Riet Correa; CASTRO, Márcio Botelho de; LEMOS, Ricardo Antônio Amaral de; CORREA, Gabriela Riet; MUSTAFA, Vanessa da Silva; CORREA, Franklin Riet
Brachiaria species are the most important grasses for cattle production in Brazil. However, a limiting factor for the use of Brachiaria spp. is their toxicity. Most outbreaks of hepatogenous photosensitization are caused by B. decumbens; however B. brizantha, B. humidicola and B. ruziziensis can also cause poisoning. The poisoning affects cattle, sheep, goats and buffalo. Sheep are more susceptible than other animal species and the young are more susceptible than adults. There are differences in susceptibility among animals of the same species and it has been suggested that this resistance is genetic. Also has been suggested that buffalo and probably some sheep are resilient, i.e. when poisoned these animals have histologic lesions and high GGT serum concentrations, but do not show clinical signs. In general, saponin concentrations are higher in growing plants, but outbreaks occur all over the year, probably due to unexplained rise in saponin concentration in the plant. A clinical syndrome of progressive weight loss and death, without photosensitization, has been reported in cattle poisoned by B. decumbens. Main preventive measures are based on the selection of resistant or resilient animals and on the development of Brachiaria species or varieties with low saponin concentration.
Acesso aberto (Open Access)
Evolução e reversibilidade das lesões neurológicas e cardíacas em ovinos intoxicados experimentalmente por Ateleia glazioviana e Tetrapterys multiglandulosa
(2008-03) ALMEIDA, Milton Begeres de; PRIEBE, Amanda Pantaleão da Silva; RIVERO, Beatriz Riet Correa; CORREA, Gabriela Riet; FISS, Letícia; RAFFI, Margarida Buss; SCHILD, Ana Lucia
To determine the reversibility of neurological and cardiac lesions in Ateleia glazioviana and Tetrapterys multiglandulosa poisoning, 3 groups of four sheep each were fed orally with the plants. In Group 1, 2 and 3, when sheep with nervous signs showed considerable increase of symptoms and risk of death, the plant administration was suspended. Group 4 with two sheep was used as control. Sheep from Group 1, fed 10g/kg during 6 days of fresh A. glazioviana collected in autumn were euthanized 8, 11, 16, and 21 days after the start of the experiment; they had shown regression of nervous signs, but had progressive cardiac lesions. Sheep from Group 2, fed during 8 days the same dose of fresh A. glazioviana collected in spring, were euthanized on days 9, 23, 38 and 68; they had shown regression of nervous signs and had no cardiac lesions. This suggests that the plant is less toxic in spring. Sheep from Group 3, fed 10g/kg during 11 days dry and ground T. multiglandulosa mixed with concentrated food, were euthanized on days 33, 33, 92 and 92; they had shown regression of nervous signs, and cardiac lesions were less severe on day 33 than on day 92. These results indicate that nervous lesions are reversible after the end of feeding, but cardiac lesions are progressive after discontinuation of the plant administration; these can be afterwards reversible if the animals do not anymore show clinical signs or die as a consequence of the poisoning. Results of those and previous experiments show that lesions of the nervous system are induced by lower doses than cardiac lesions and occur within a shorter period, what suggests that in spontaneous cases cardiac signs are always preceded by nervous signs, and that nervous signs can occur in the absence of cardiac lesions.
Acesso aberto (Open Access)
Intoxicação por Brachiaria spp. em ruminantes: revisão bibliográfica e alterações histológicas em fígados e linfonodos mesentéricos de bubalinos
(Universidade Federal do Pará, 2010-02-12) RIVERO, Beatriz Riet Correa; RIVERO, Gabriela Riet Correa; http://lattes.cnpq.br/7540534565167837
Acesso aberto (Open Access)
Plantas que causam alterações mecânicas ou traumáticas em ruminantes e equinos, com ênfase em Stipa spp. (Gramineae)
(2011-06) RIVERO, Beatriz Riet Correa; RIVERO, Gabriela Riet Correa; CORREA, Franklin Riet
Many plants cause mechanical injury in horses and ruminants, as those that cause traumatism on skin and mucosa, and those that cause lesions in the digestive system, including esophagus obstruction, rumen overload, and intestinal obstruction. In this paper, plants causing mechanical injury to ruminants and horses in Brazil are reviewed, and an outbreak in sheep of mechanical injury of the skin by Stipa sp. in Uruguay is reported. The sheep, mainly lambs, showed large number of fruits of Stipa sp. in the wool, some of them penetrating the skin, panniculus adiposus, and cutaneous trunci muscle, causing multifocal dermatitis and panniculitis.
Acesso aberto (Open Access)
Reemerging of natural infection by Trypanosoma evansi in horses in Arari, Marajó Island, Brazil
(Universidade Federal do Pará, 2016-12) SILVA, Josileide Araújo da; DOMICIANO, Tarcísio Oliveira; MONTÃO, Daniele Pina; SOUSA, Paulo Geovani Silva; RAMOS, Leandro Lopes; PAREDES, Laura Jamille Argolo; GONZALEZ MONTEIRO, Silvia; RIVERO, Beatriz Riet Correa; SCOFIELD, Alessandra; BEZERRA JÚNIOR, Pedro; BEZERRA, Isis Abel; CERQUEIRA, Valíria Duarte
Two outbreaks of trypanosomiasis by Trypanosoma evansi in horses in the municipality of Chaves, Marajó Island, Pará State, Brazil are reported. The first outbreak occurred in April 2011 in a farm with 147 horses; of these, 47 (31.97%) got sick, and 40 (27.21%) died. The second outbreak occurred in May 2012 and involved nine properties. Of a total of 679 horses, 209 (30.07%) got sick, and 183 (26.97%) died. The main clinical signs observed in these horses were weight loss, abdominal edema, toe dragging, and pelvic muscle atrophy. Necropsy was performed in two horses, one from each outbreak. Macroscopic alterations were not seen in the horse from the first outbreak; however, the horse from the second outbreak exhibited emaciation, pallor and icterus, as well as enlarged spleen with prominent white pulp at cut surface. Histopathology of the central nervous system of both animals revealed mild to severe, diffuse lymphoplasmacytic encephalitis, with presence of Mott cells. Immunohistochemistry for T. evansi revealed structures similar to intralesional trypomastigote forms. Between November and December of 2013, an epidemiological survey was carried out in the municipalities of Cachoeira do Arari, Santa Cruz do Arari, Salvaterra, Soure, and Chaves. Only Santa Cruz do Arari and Chaves had reported cases of the disease. Blood samples were collected from 243 horses for detection of T. evansi DNA by polymerase chain reaction (PCR) and 20 were positive.