Asociación de plantas del género Crotalaria Spp. con la enfermedad caballo loco en Isla de Pascua
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2016
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
Desde la década de los 80 los caballos en isla de pascua han mostrado signos de anorexia, perdida de peso combinado con signos neurológicos hasta su muerte. Los isleños se refieren a estos como “Caballo loco”. La etiología es desconocida, pero se sugiere que es por consumo de Crotalaria spp., plantas que contienen alcaloides pirrolizidínicos. El objetivo de este trabajo es describir el comportamiento alimenticio de los caballos y relacionarlo con las manifestaciones neurológicas. La investigación se realizó entre 2010-2015, documentando los hábitos alimenticios de los caballos y la distribución de Crotalaria spp. en la isla. 55 equinos fueron examinados y 16 fueron analizados con test sanguíneos, serológicos, urinarios, ultrasonido y biopsia de hígado y exámenes toxicológicos en dichas plantas e hígado. Se realizó necropsia en tres individuos. Se encontró C. grahamiana distribuida alrededor de toda la isla, siendo consumida continuamente y con preferencia respecto a otras pasturas, en menor proporción se encontró C. pallida. En la necropsia se apreció hepatomegalia con aspecto moteado. Los animales presentaron valores alterados de enzimas hepáticas e hiperamonemia, la ecografía reveló heterogeneidad del hígado y microscopicamente se observó fibrosis, megalocitosis, hiperplasia de conductos biliares y desorden de pigmentos. Los test serológicos para enfermedades virales con signos similares de hepatopatía fueron negativos. Exámenes toxicológicos identificaron cuantitativamente Monocrotalina en C. grahamiana (310.17 to 1.04 ug/g) y en hígado (0.137 to 0.014 ug/g) con correlación positiva entre ambas. Se concluye que esta planta sería la causa más razonable de encefalopatía hepática en equinos por consumo crónico de la planta.
Since the 1980’s, horses in Easter Island have shown anorexia, weight loss and neurological symptoms leading to their death. The etiology of these symptoms – referred by the locals as “Crazy Horse’s”- is unknown, but it is suggest it might be caused by the ingestion of Crotalaria spp., a plant containing pirrolizidinic alkaloids. This investigation aimed to describe the alimentary behavior of the horses and link it to the appearance of the pathology. During the research (2010-2015) the alimentary habits of the horses were registered, as well as the distribution of Crotalaria spp. in the island. 55 horses were examined and 16 subjected to blood, serological and urinary tests, liver biopsies and ultrasounds; toxicological tests were performed on the horses’ livers and the plant in question. A necropsy was performed on three subjects. C. grahamiana, which was found to be widely spread, was ingested continuously and preferred over other pastures. C. pallida was found in lesser proportion. The necropsy revealed hepatomegaly and liver mottling. Tests showed abnormal values for hepatic enzymes and hyperammonemia; the liver sonography revealed heterogeneity and echogenicity, while the biopsy showed fibrosis, hepatic megalocytosis, bile duct hyperplasia and pigmentary disorders. Serological tests for viral diseases which could cause similar hepatic pathology resulted negative. Monocrotaline was quantitatively identified in C. grahamiana (310.17 to 1.04 ug/g) and in the livers (0.137 to 0.014 ug/g), with a positive correlation between both. It is concluded that the chronic ingestion of this plant constitutes the most plausible cause of the observed equine hepatic encephalopathy.
Since the 1980’s, horses in Easter Island have shown anorexia, weight loss and neurological symptoms leading to their death. The etiology of these symptoms – referred by the locals as “Crazy Horse’s”- is unknown, but it is suggest it might be caused by the ingestion of Crotalaria spp., a plant containing pirrolizidinic alkaloids. This investigation aimed to describe the alimentary behavior of the horses and link it to the appearance of the pathology. During the research (2010-2015) the alimentary habits of the horses were registered, as well as the distribution of Crotalaria spp. in the island. 55 horses were examined and 16 subjected to blood, serological and urinary tests, liver biopsies and ultrasounds; toxicological tests were performed on the horses’ livers and the plant in question. A necropsy was performed on three subjects. C. grahamiana, which was found to be widely spread, was ingested continuously and preferred over other pastures. C. pallida was found in lesser proportion. The necropsy revealed hepatomegaly and liver mottling. Tests showed abnormal values for hepatic enzymes and hyperammonemia; the liver sonography revealed heterogeneity and echogenicity, while the biopsy showed fibrosis, hepatic megalocytosis, bile duct hyperplasia and pigmentary disorders. Serological tests for viral diseases which could cause similar hepatic pathology resulted negative. Monocrotaline was quantitatively identified in C. grahamiana (310.17 to 1.04 ug/g) and in the livers (0.137 to 0.014 ug/g), with a positive correlation between both. It is concluded that the chronic ingestion of this plant constitutes the most plausible cause of the observed equine hepatic encephalopathy.
Notas
Tesis (Doctor en Medicina Veterinaria)
Palabras clave
Caballos, Enfermedades, Plantas Tóxicas, Crotalaria Grahamiana, Chile, Isla de Pascua