Intoxication of llamas by Astragalus punae in Argentina

Authors: MARIN, RAUL - National University Of Jujuy; Gardner, Dale; ARMIEN, ANIBAL - University Of California, Davis; FORTUNATO, RENNE - Darwinion Botanical Institute; UZAL, FRANCISCO - University Of California, Davis

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2022
Publication Date: 7/1/2022
Citation: Marin, R.E., Gardner, D.R., Armien, A.G., Fortunato, R.H., Uzal, F.A. 2022. Intoxication of llamas by Astragalus punae in Argentina. Journal of Veterinary Diagnostic Investigation. 34(4):674-678. https://doi.org/10.1177/10406387221094272.
DOI: https://doi.org/10.1177/10406387221094272

Interpretive Summary: A case of poisoning in llamas was observed in the northwestern region of Argentina (Jujuyprovinece). Animals were observed to lack coordination in the hind limbs with progressive loss of body condition over a 15 day period. The clinical symptoms were similar to those of locoisim observed in animals consuming plants that contain the alkaloid swainsonine which causes neurovisceral disease and wasting disease. A survey of the grazing area found abundant specimens of a plant identified as Astragalus punae. Histologic examination found tissue damage consistent with locoisim and analysis of A. punae plants samples taken from the grazing area were positive for swainsoine. Based on clinical history, histological examination, and plant analysis, the diagnosis of swainsonine toxicosis due to consumption of A. punae was made. This is the first report of intoxication by A. punae in animals.

Technical Abstract: Several plants that contain indolizidine alkaloids, including swainsonine, are toxic to livestock, causing dysfunctional lysosomes and storage disease. Swainsonine induces a neurovisceral disease, known as locoism, in sheep, goats, and cattle, which occurs in several parts of the world, including, but not limited to, the western United States, China, and parts of Australia. In South America, locoism has been described in the Andean region of Argentina affecting sheep, cattle, and llamas. Intoxication by consumption of Astragalus punae was suspected in 4 llamas in Jujuy Province, northwestern Argentina. The grazing area contained abundant specimens of A. punae. The clinical course was ~15 d, and included moderate ataxia, incoordination of hindlimbs, and progressive loss of body condition. Microscopically, fine cytoplasmic microvacuolation was observed in the proximal convoluted renal tubules. Ultrastructurally, these changes consisted of severely dilated lysosomes. Swainsonine was detected in stem and leaf samples of A. punae at a concentration of 0.06%. Based on clinical history and signs, histologic and ultrastructural changes, and plant analysis, a diagnosis of swainsonine toxicosis caused by consumption of A. punae was made, which has not been reported previously, to our knowledge.