were observed in horses on 8 farms in the semiarid region of Paraíba and Ceará. C. retusa was found in all farms. The main clinical signs were characteristic of hepatic encephalopathy, with dullness or hyperexcitability, head pressing, compulsive walking or circling and, occasionally, violent uncontrollable galloping. Decreased cranial nerve reflexes, ataxia and weakness were also observed. Other clinical signs were anorexia, weight loss, photosensitization and jaundice. The clinical manifestation period varied from 4 to 40 days, but most horses had a previous history of weight loss. At necropsy the livers were hard, with irregular surface and white areas mixed with dark red areas and increased lobular pattern. Mild jaundice, ascitis, hydropericardium and hydrothorax were also observed. Edema and moderate congestion were seen in the lungs. Histologic changes of the liver were characterized by fibrosis, mainly periportal, megalocitosis and bile duct cell proliferation. Multifocal areas of centrilobular or midzonal hemorrhages were also observed. Centrilobular hemorrhagic necrosis was present in two horses. Alzheimer type II astrocytes were observed, isolated or in groups, mainly in the caudate nucleus and cortex in 4 horses. The poisoning was experimentally produced in 1 adult horse and 3 adult donkeys. The horse received daily 100 g of C. retusa seeds and died 52 days after the beginning of the experiment. The dried whole C. retusa was mixed with grass and given to the 3 experimental donkeys at daily doses of 10g/kg, 5g/kg and 2.5g/kg, respectively. The donkey treated with 5g per kg died 48 days after beginning of the experiment and the other two were sacrificed at 120 days. Clinical signs and pathology were similar to those observed in spontaneous cases, but Alhzeimer type II astrocytes were observed only in the donkey that died 48 days after the beginning of ingestion of the plant material. The concentration of monocrotaline in the whole plant given to the donkeys was 0.5%.INDEX TERMS: Poisonous plants, plant poisoning, Crotalaria retusa, Fabaceae, hepatic cirrhosis, horse, pirrolizidine alkaloids.

Cases of poisoning by pyrrolizidine alkaloids (PAs) in ruminants and horses were surveilled retrospectively by accessing the files of two veterinary diagnostic laboratories in southern and northeastern Brazil. The data obtained were compared with those withdrawn from the literature and pertaining to outbreaks of the toxicosis in Brazil where it is associated with the ingestion of PAs-containing plants from the genera Senecio, Crotalaria and Echium. Acute and chronic forms of the toxicosis were encountered. Acute disease was observed in association with the ingestion of Crotalaria retusa in sheep and goats. C. retusa and Senecio spp. were also responsible for chronic poisoning in cattle, horses and sheep. PAs poisoning is an important cause of death in livestock in Brazil. It is the major cause of death in cattle in the Central region of Rio Grande do Sul and one of the major causes of death in horses in the state of Paraíba. The epidemiology, clinical signs, pathology, and importance of acute and chronic toxicoses are described and discussed.

A 12-year-old

ArticleCrotalaria retusa L. (family Fabaceae; rattleweed) is a weed reported in the state of Paraíba, northeastern Brazil, as a cause of chronic poisoning in horses 11 and acute poisoning in sheep. 10,13 Cases of hepatic fibrosis associated with consumption of C. retusa have been reported in cattle, 12 but could not be reproduced experimentally in this species by the continuous administration of low doses of monocrotaline (MCT), the principle dehydropyrrolizidine alkaloid (DHPA) produced by C. retusa.2 Lesions of chronic DHPA-related poisoning have been produced experimentally following administration of Jacobaea vulgaris (syn. Senecio jacobaea) to goats. 6 However, in dosing experiments with Crotalaria saltiana 3 and Heliotropium ovalifolium, 1 the typical lesions of acute or chronic DHPA-related poisoning were not reported. In sheep in northeastern Brazil, the ingestion of seeds of C. retusa cause acute liver necrosis. 12,13 In the current report, centrilobular liver necrosis is reported in goats that were ingesting C. retusa seed while occupying a paddock invaded by this plant. To demonstrate the association of the disease with the ingestion of C. retusa, the seeds of the plant were administered to experimental goats.A natural outbreak of poisoning associated with seeding C. retusa occurred in the municipality of Patos (Paraíba, Brazil) in September 2008. From a total of 30 adult and young crossbred goats, 4 (13.3%) adults were overtly affected and subsequently died. The animals were grazed extensively in an area of native pastures (named caatinga), but some encroached on an agricultural area of the farm and consumed seeds and leaves of C. retusa that infested the area. The main clinical signs, described by the farmer, were frothy salivation and lethargy. Death occurred within 24-48 hr after the onset of clinical signs. One goat, found dead at the time of the visit, was necropsied and its tissues examined histologically.The liver showed accentuation of the lobular pattern characterized by reddened areas interspersed with pale areas, distributed throughout the capsular surface and parenchyma. There was also a focal area of hemorrhage on the liver surface with adhesions to the peritoneum and diaphragm. Multiple hemorrhages were observed in subcutaneous tissue, abdominal external oblique muscle, and greater omentum. The lung was reddish and blood flooded from the cut surface. Reddish fluid was present in the pericardial sac, and petechiae were observed in the pericardium and endocardium. Histologically, the liver showed centrilobular hemorrhagic necrosis. The hepatocytes of the midzonal region were swollen or had moderate vacuolation of the cytoplasm. No significant lesions were observed in other organs examined, including lung, heart, kidneys, gall bladder, lymph nodes, small and large intestine, prestomachs, and nervous system.To investigate the potential role of C. retusa in the poisoning outbreak, more seeds were collected in the municipalities of São José do Bonfim and Coremas in the state of Paraíba. High-...