A lysosomal storage disease induced by Ipomoea carnea in goats in Mozambique

A novel plant-induced lysosomal storage disease was observed in goats from a village in Mozambique. Affected animals were ataxic, with head tremors an d nystagmus. Because of a lack of suitable feed, the animals consumed an ex otic hedge plant growing in the village that was identified as Ipomoea carn ea (shrubby morning glory, Convolvulaceae). The toxicosis was reproduced by feeding I. carnea plant material to goats. In acute cases, histologic chan ges in the brain and spinal cord comprised widespread cytoplasmic vacuolati on of neurons and glial cells in association with axonal spheroid formation . Ultrastructurally, cytoplasmic storage vacuoles in neurons were membrane bound and consistent with lysosomes. Cytoplasmic vacuolation was also found in neurons in the submucosal and mesenteric plexuses in the small intestin e, in renal tubular epithelial cells, and in macrophage-phagocytic cells in the spleen and lymph nodes in acute cases. Residual alterations in the bra in in chronic cases revealed predominantly cerebellar lesions characterized by loss of Purkinje neurons and gliosis of the Purkinje cell layer. Analys is of I. carnea plant material by gas chromatography-mass spectrometry esta blished the presence of the mannosidase inhibitor swainsonine and 2 glycosi dase inhibitors, calystegine B-2 and calystegine C-1, consistent with a pla nt-induced a-mannosidosis in the goats. The described storage disorder is a nalogous to the lysosomal storage diseases induced by ingestion of locoweed s (Astragalus and Oxytropis) and poison peas (Swainsona).