Abstract
Here we describe 2 outbreaks of intoxication by Ricinus communis in cattle in Argentina. In outbreak 1, in 2010, 180 heifers were introduced to a paddock heavily invaded by R. communis. Thirty-two animals developed watery diarrhea, and 6 of them were drooling, and had constant chewing motions, blindness, incoordination, depression, and prostration. Four affected animals died 12-14 h after the onset of clinical signs; another died 4 d later. The surviving 27 animals were removed from the paddock and recovered. At autopsy, several organs were congested and hemorrhagic, and abundant pericarps, leaves, and seeds of R. communis were found in the rumen content. The main microscopic lesion was acute, diffuse, superficial necrotizing gastroenteritis, and intestinal congestion and hemorrhage. In outbreak 2, in 2013, severe neurologic signs were observed in 12 of 300 cows after being introduced into a corn paddock without grain production that had been severely invaded by R. communis. Affected animals were excited and had tremors, drooling, incoordination, and prostration. The herd was immediately transferred to another paddock, and all affected cows recovered without treatment. In outbreak 1, the clinical signs and lesions were characteristic of simultaneous poisoning by R. communis fruits, which contain ricin and cause mainly digestive signs and lesions, and by leaves and pericarps, which contain ricinine and cause nervous signs. In outbreak 2, clinical signs and the recovery of the animals suggest that the intoxication was caused by ricinine, which is present in the leaves of R. communis.