Intoxicação por plantas que contêm swainsonina no Brasil

Abstract

Swainsonine-containing plants comprise a very important group of toxic plants in Brazil, including Ipomoea carnea subsp. fistulosa, Ipomoea riedelii, Ipomoea sericophyla, Ipomoea verbascoidea, Turbina cordata and Sida carpinifolia, which cause a glycoprotein storage disease in goats, and with less frequency in cattle, horses, sheep, and deer. A characteristic of swainsonine poisoning is that the animals that eat these plants develop the habit of eating them compulsively and, by social facilitation, induce other animals of the same species to eat them. Clinical signs of the poisoning are rough hair coat, weight loss, and nervous signs associated mainly with cerebellar and brain stem lesions. Weight losses or decreased weight gains still occurring also in animals with chronic clinical signs removed from the areas where the plants occur. Reproductive losses are also reported. Chronically affected animals, also without still ingesting the plant, are more susceptible to gastrointestinal parasites. Cerebellar atrophy has been observed grossly in chronic cases. Main histologic lesions are vacuolation of neurons, epithelial cells of the pancreas and kidney, thyroid follicular cells, hepatocytes, and macrophages of lymphoid organs. To control the poisoning animals must be removed immediately from the areas invaded by the plant. The only preventive measure to prevent the ingestion of the plant is their elimination from invaded areas or through conditioned food aversion.