Waxy-leaf Nightshade

Solanum glaucophyllum (commonly known as waxy-leaf nightshade and also referred to as S. glaucum and S. malacoxylon) is a toxic plant which is known for its calcinogenic effects, leading to development of enzootic calcinosis. The main active components in calcinogenic plants are 1,25-dihydroxyvitamin D3 (aka Vitamin D). The quantity varies depending on the genetic variety of the plant and the environmental conditions under which the plant has grown.

An outbreak of enzootic calcinosis recently occurred in a herd of horses grazing in a pasture heavily contaminated with the plant, in Buenos Aires province in Argentina. 10 of the 110 horses who grazed the pasture developed clinical signs of poisoning, and 6 others died.

What Waxy-leaf nightshade looks like.

Waxy-leaf nightshade is a rhizomatous shrub or slender 0.5-4 m high treelet (sapling), with simple, narrowly elliptical leaves and bluish-purple flowers. The fruit it produces are blue-black globose berries (1 to 2 cm in diameter).

Where waxy-leaf nightshade grows.

The plant is native to parts of South America but it is cultivated and naturalized throughout the world. It is most likely to be found growing in low, swampy areas at margins of marshes and ponds.

What poisoning does. The plant causes poisoning in grazing animals living in low-lying wet areas, and documented several times in Argentina, Brazil and Uruguay. Most affected horses may develop a loss of appetite, weight loss, wasting, and stiffness. Later stages often involve inability to completely extend the joints. Blood analysis reveals higher than normal levels of calcium and inorganic phosphorus, associated with deposition of calcified material in soft tissues, especially the heart, arteries, lungs, and kidneys, as well as osteosclerosis. The clinical signs are similar to those induced by vitamin D overdose.

Necropsy confirmation. Severe mineralization of the aorta, pulmonary arteries, heart, and lungs, consistent with enzootic calcinosis.