Lisosomal storage disease caused by ingestion of Astragalus spp in llamas: an emergent concern

Lysosomal storage diseases are inherited or acquired disorders characterized by dysfunctional lysosomes that lead to intracytoplasmic accumulation of undegraded substrates, causing impaired cellular function and death. Many acquired lysosomal storage diseases are produced by toxic plants, which have indolizidine alkaloids, including swainsonine, that inhibits lysosomal α-mannosidase and Golgi α-mannosidase II. Swainsonine-induced nervous disease associated with various plants has been reported, including species of the genus Astragalus, Sida, Oxitropis, Swainsona, and Ipomoea. Two species of Astragalus (i.e. Astragalus garbancillo and Astragalus punae) have been found to cause neurologic disease in llamas. In addition, A. garbancillo was also associated with malformations in the offspring, and possibly abortions and neonatal mortality in llamas. The diagnosis of Astragalus spp. intoxication is established based on clinical signs, microscopic and ultrastructural findings, lectin histochemistry, abundance of these plants in the grazing area and determination of swainsonine in plant specimens.