Background: The Senna occidentalis poisoning occurs by the ingestion of seeds, leaves and stem of the plant, causing
degenerative myopathy lesion. In addition, a several animals species are affected. Outbreaks are related with the ration consumption
contaminated by seeds. However, few cases of spontaneous ingestion of the plant in fields were described. A rapid clinical
disease is characterized by diarrhea, colic and tenesmus. Afterwards, muscular lesions and brownish-urine were revealed. In the
end of the disease course, serum levels of creatine kinase (CK) and aspartate aminotransferase (AST) are increased. The aim of
this study is to describe an outbreak of S. occidentalis poisoning in live cattle, in Triunfo, Rio Grande do Sul, Brazil, occurred in
May 2008.
Case: Epidemiological and clinical signs were obtained from the owner and veterinary responsible of this flock. Also, necropsy
exam was performed in two cattle. Organs samples were collected and fixed in formalin 10%, one of which has blood and urine
samples taken to biochemical test and urinalysis respectively. The remaining nine cattle had the blood samples collected too
biochemichal analysis.
Discussion: In a herd of twelve cattle were fed with native pasture, nine of which showed high levels of CK, and one animal had
a high levels of AST in biochemistry analysis. Three animals died with clinical signs of muscular weakness, apathy, dark brown
urine, intense salivation, dyspnea and lateral recumbency. At necroscopy examination, the skeletal muscles were pale, especially
in pelvic members, and the uninary bladder contained dark brown urine. The histopathological findings were severe multifocal
degeneration and necrosis of the skeletal muscles fibers, renal tubular degeneration and amorphous eosinophilic material inside
them. The liver showed congestion and discret centrolobular necrosis. At the area where the animals had access were found a
large quantity of S. occidentalis with consumption signs. The diagnosis was based on the epidemiological and clinical data, also,
the necropsy, hitopathological findings, urinalysis and biochemistry evaluation. The depression pasture that occurs between
on May and on June and the increase of the toxicity of this plant due to the presence of seeds made possible the animals
poisoning. The clinical signs are related to skeletal muscle necrosis because of intaking the plant. The myoglobinuria results
from the muscle fiber destruction and in consequence of liberation of myoglobin to blood circulation, which is eliminated in the
urine. In the final disease course, serum levels elevation of CK and AST due to skeletal muscle necrosis were observed, which
explains the values obtained in the sample dosage from the animal that were performed necropsy exam. The high levels of CK in
nine animals, of 10 samples that were collected indicate that the myocytes necrosis is occurring, or occurred recently. Also, it
indicates that these animals fed the plant. However, the absence of increase of AST serum levels in all the samples of the survival
herd is related to the minor intensity of the muscles lesions. CK is a cytosolic enzyme, on the other hand, AST is an enzyme
presents in mitochondria and cytosol. In addition, it needs a larger lesion to be liberated it in the blood circulation. The differential
diagnosis should be realized with diseases that follow with hemoglobinuria, with myocardium or skeletal muscles necrosis, also,
with a long period of recumbence and locomotion difficulty and/or nervous signs.
