Poisoning by Senecio brasiliensis in horses in northern Rio Grande do Sul

ABSTRACT

Background: In various regions of Brazil, horses and cattle are considered the most susceptible animals to plant poisoning. The plants of the genus Senecio are the most important in Rio Grande do Sul because they have the active principleknown as the pyrrolizidine alkaloid. Its diagnosis is made through epidemiology, clinical signs and histopathologicalanalysis, either of the tissues obtained by biopsy or necropsy. The objective of this study was to report and characterizethe epidemiological, clinical and anatomopathological findings of three cases of natural poisoning by Senecio brasiliensisin horses assisted at the Hospital Veterinário (HV) of the Universidade de Passo Fundo (UPF).Cases Three traction horses, two males and one female, were admitted at the HV-UPF for clinical care. The animals werepresenting anorexia, weight loss, dysmetria, proprioceptive deficit and signs suggestive of colic. The epidemiological studyrevealed that the sites where these animals were located were infested by Senecio brasiliensis. The support therapy usedfor equine colic in all three cases was unsuccessful. One of the animals died and the other two were euthanized, all threeof them being reffered for necropsy. The post-mortem findings were mainly found in the liver, which showed accentuationof the lobular pattern and the appearance of nutmeg. During necropsy, fragments of organs from thoracic and abdominalcavities and central nervous system were collected and fixed in 10% buffered formalin. Subsequently, the samples wereprocessed chemically, submitted to cuts of five micrometers of thickness and stained with hematoxylin and eosin for microscopic analysis. Microscopically, the liver of all three horses presented megalocytosis, fibrosis and bile ducts hyperplasia.In the central nervous system, spongiosis and the presence of Alzheimer type II astrocytes were observed. Thus, throughthe association of information, the diagnosis of...