RESUMODeterminaram-se as características eletrocardiográficas de amplitude, duração, ritmo e eixo cardíaco no plano frontal de potros, sobreanos e éguas prenhes clinicamente normais, da raça Puro Sangue Inglês. Estudaram-se 50 potros e 50 sobreanos, machos e fêmeas, e 11 éguas prenhes. Concluiu-se que a freqüência cardíaca diminui com a idade e que nos potros e sobreanos as características apresentaram valores intermediários entre os valores padrão de neonatos e adultos. Nos sobreanos eles estão mais próximos dos de referência para adultos. Nas éguas em gestação a única diferença observada com o padrão foi o leve desvio para a direita do eixo cardíaco.Palavras-chave: eletrocardiograma, eqüino, potro, sobreano, égua prenhe
ABSTRACT
BackgroundRickettsia rickettsii is vectored by ticks, and some vertebrate hosts can be sources of infection to ticks during bacteremic periods. In Brazil, the main vector for R. rickettsii is the tick Amblyomma sculptum, a member of the A. cajennense complex. Horses, in turn, are one of the major hosts for A. sculptum. In this study, horses experimentally infected with R. rickettsii were assessed for clinical changes and their capability to transmit the infection to A. sculptum ticks.MethodsFour horses were infected with R. rickettsii through either intraperitoneal injection or infestation with R. rickettsii-infected A. sculptum ticks. Simultaneously, the animals were infested with non-infected A. sculptum ticks. The horses were monitored for 30 days by clinical examination, hematological and biochemical tests, real-time PCR of blood for the detection of Rickettsia, and inoculation of blood in guinea pigs. IgG antibody titers were followed until the horses have shown seronegativity or until the end of the experiment. Uninfected ticks that fed on horses were subjected to real-time PCR and/or were fed on susceptible rabbits.ResultsThe horses showed no clinical, hematological or blood biochemical alterations, and bacteremia was not detected by real-time PCR or by inoculation of horse blood into guinea pigs. Anti-R. rickettsii antibodies were detected in horses from 10 days to 2 years after infection. Uninfected ticks, after feeding on infected horses, showed 2.1 % positivity in real-time PCR, but failed to transmit the infection to rabbits at a next feeding stage.ConclusionsRickettsia rickettsii-infected horses did not manifest illness and are not competent amplifier hosts of R. rickettsii for A. sculptum ticks.
Foram realizados estudos comparativos dos exames citológicos obtidos a partir de amostras dos lavados traqueobrônquico (LTB) e broncoalveolar (LBA) de cavalos clinicamente sadios. Foram colhidas 25 amostras pela técnica do LTB (25 animais) e 25 amostras pela técnica do LBA (5 animais). A suspensão celular dos lavados foi centrifugada, confeccionando-se lâminas coradas pelo método de Rosenfeld. A contagem diferencial mostrou predominância de macrófagos em ambas as técnicas de colheita, confirmando a possibilidade de sua utilização para obter amostras celulares das vias aéreas distais. Observou-se diferença na proporção de macrófagos e linfócitos entre as técnicas dos lavados traqueobrônquico e broncoalveolar. As porcentagens de macrófagos e linfócitos observadas foram de 81,51±11,06% e 2,91±3,44% no LTB e de 54,78±15,92% e 33,70±14,41% no LBA, respectivamente. Também notou-se ausência de células epiteliais cilíndricas e produtoras de muco em LBA, indicando que essas amostras são provenientes da população alveolar e que esta técnica não traumatizou as vias aéreas proximais. Os demais tipos celulares foram identificados em proporções semelhantes e em pequenas quantidades em ambas as técnicas. As características morfológicas dos tipos celulares foram semelhantes nas duas técnicas.
ABSTRACT. - Bronchopneumonia is important for world livestock production and one of the major causes of calf mortality during the first months of life. The preventive and therapeutic measures adopted for the disease in calves in Brazil are usually based on the results of international studies; however there is not enough known which bacteria are implicated. In the first month of life calves show immaturity of their immune system, what has been little studied in regard to pneumonia. The present investigation sought to study neonate bronchopneumonia in calves, to identify which bacteria are present in the respiratory tract of healthy and, with naturally acquired pneumonia calves, to analyze the pulmonary cytological response against pathogens. For this purpose, samples of the respiratory tract were collected by tracheocenthesis. It was noted that the microflora of the tracheobronchial region of healthy and diseased calves was the same, but they were different from the one reported by international papers. The flora was constituted mainly by Staphylococcus sp., Bacillus sp., Streptococcus sp., Pseudomonas aeruginosa and enterobacteriae, allowing to infer that the prophylactic and therapeutic measures adopted internationally may not be as effective for the Brazilian condition. It was also found that newborn calves have an approximate ratio of 1:1 of macrophages and neutrophils in the tracheobronchial region when they were healthy, reaching a ratio of approximately 1:3 of macrophages and neutrophils when they were with bronchopneumonia. Probably, these profiles are characteristic of the age, a period when exists immaturity of the immune system and influenced by management factors which lead to greater inhalation of bacterial agents. RESUMO.-As broncopneumonias são afecções importantes na pecuária mundial, representando uma das principais causas de mortalidade de bezerros nos primeiros meses de vida. As medidas preventivas e terapêuticas adotadas geralmente são baseadas em resultados de estudos internacionais, não se conhecendo as bactérias implicadas nos quadros pneumônicos em animais criados no Brasil. Aliado a isso, no primeiro mês de vida, os bezerros demonstram imaturidade do sistema imune, o que tem sido pouco estudado em quadros pneumônicos. Desta maneira, objetivou--se estudar as broncopneumonias em bezerros neonatos,
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