Clinical communication — Kliniese mededeling Nicotiana glauca poisoning in ostriches (Struthio camelus)

INTRODUCTION Nicotiana glauca (wild tobacco, tree tobacco), a member of the Solanaceae family, is a slender shrub or a small erect tree growing up to 5 m high with long, lax branches (Fig. 1). This plant is a native of Argentina that has become widespread in South Africa, occurring mostly on disturbed soil such as old lands, trampled areas and road verges. It is also a common weed along inland rivers and is occasionally even found as an ornamental in gardens. Although N. glauca is a very poisonous plant, it is seldom incriminated in poisoning of livestock in South Africa and is therefore considered to be mainly of academic interest. Nevertheless, if sufficient amounts of this plant are ingested by stock, poisoning and even death can result. Mortalities have been reported in ostriches (Struthio camelus). Since 3 reports at the turn of the previous century there has been a dearth of scientific literature on outbreaks in ostriches. In 1903, Hutcheon reported that farmers implicated wild tobacco as a cause of death in their birds. He described the following symptoms: ‘staggering gait, spasmodic contractions of the voluntary muscles followed by stupor, the birds sit down and throw their heads about, finally, the neck is doubled right back and the head laid on the body; death being due to coma’. Nicotiana glauca contains the piperidinepyridine alkaloid, anabasine, which is closely related to nicotine, derived from N. tabacum. Anabasine acts as an agonist at peripheral nicotinic receptors. The nicotinic receptors of the autonomic ganglia and the neuromuscular junctions are initially stimulated, but this is invariably followed by prolonged blocking. Strong stimulation of the central nervous system also occurs resulting in tremors followed by convulsions. Death is ascribed to respiratory paralysis.