ABSTRACT
Mascagnia rigida, a vine or shrub from the Malpighiaceae family popularly named in Brazil as ‘tingui’ and ‘timbó’, is one of most well-known poisonous plants from Northeast and part of Southwest Brazil. It represents a significant cause of death in cattle and goats. In light of the lack of any previous published report of any case of its natural poisoning in sheep, the present article reports such poisoning for the first time, describing four outbreaks of natural poisoning by M. rigida in sheep. The outbreaks occurred in the counties of Mossoró (3 outbreaks) and Upanema (1 outbreak), state of Rio Grande do Norte, Brazil, in 2006. Clinical manifestations in affected animals consisted of apathy, muscle trembling, tachycardia, difficulty in standing up, dyspnea, convulsions, and death. Histological lesions were multifocal infiltrate of lymphocytes in the myocardium associated with edema and congestion of myocytes, and diffuse vacuolar degeneration in hepatocytes. In order to confirm the etiology of the disease, an experiment was performed with two female healthy sheep that received daily fresh leaves of M. rigida. On the first and second days the plant was administered at a dose of 10 g/kg body weight, whereas on the third and fourth days the dose was 20 g/kg. About 2 hours after the last dosing (fourth day) the animals presented clinical disturbances similar to natural poisoning, including death. Pathological findings were also similar to natural cases. Thus, sheep are also naturally affected by M. rigida poisoning, and there is a cumulative effect, the total lethal dose being 60 g/kg of body weight.
KEY WORDS
Poisonous plants;
Mascagnia rigida
; plant poisoning; sheep
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