Intoxicação espontânea por Ricinus communis em ovinos / Spontaneous poisoning by Ricinus communis in sheep

ABSTRACT

Background: Ricinus communis (castor bean) is an arbustive plant, popularly known in Brazil as “mamona”. This plant is widely distributed both as a weed in pastures and in specific cultures. All parts of the plant are poisonous and contain the toxic substance ricin, especially the seeds, leaves and pericarp. The ingestion of leaves and pericarp may cause neurological signs. Gross findings are unspecific, however the main finding is the presence of leaves and seeds in the ruminal content. This report aims to describe the clinical, epidemiological and pathological features of a spontaneous poisoning by R. communis in two sheep.Cases During the month of March of 2015, six sheep that were kept in a native pasture with high amounts of capimannoni (Eragrostis plana) and received alfalfa hay, had access in the morning to an area infested by R. communis, which was previously cut. Two of these animals presented in the same day at the afternoon clinical signs of apathy, dyspnea and recumbency, followed by death. The inspection of the area infested by R. communis revealed that large amounts of seeds and leaves of this plant were consumed. The two sheep were submitted to necropsy, where multiple samples were collected and processed routinely for histology. Grossly, there were cyanotic mucosae and alimentary content around the nostrils. The ruminal content was dry and showed large amounts of partially digested leaves and seeds. Microscopically, rumen, reticulum and omasum had mild hydropic degeneration in the mucosa, in addition to a mild inflammatory infiltrate composed of lymphocytes and plasma cells.[...]