Nerium species

Abstract

DISTRIBUTION: • An exotic plant that can be found in suburban gardens throughout southern Africa. • Originally from Europe. • Nerium oleander is now a declared weed in South Africa.

BOTANICAL DESCRIPTION: General: Large multi-stemmed evergreen shrub. Leaves: Stiff, dark green, narrow, hairless leaves. They are usually arranged in whorls of three and have a conspicuous, closely parallel venation. All parts of the plant contain watery latex. Flowers: Showy flowers are clustered at the ends of the branches. They can be dark red, pink or white and “single” with 5 petals (N. oleander) or “double”, pink and fragrant (N. indicum). Fruit: A pod that splits open longitudinally to reveal the tufted seeds, which are distributed by the wind.

TOXIC PRINCIPLE: Nerium oleander contains several cardenolides such as oleandrin and adigosid.

SYNDROME: Acute poisoning by cardenolide-containing plants. Also refer to “Tulp poisoning”.

SYSTEMS AFFECTED: Cardiovascular system.

CLINICAL SIGNS: • Paralysis • Breathing difficulties • Quick, but weak heartbeat.

NECROPSY: Macroscopical findings: • Not specific - rather negative • Subepi- and endocardial haemorrhages • Lung oedema, congestion, emphysema • Ruminal atony and enteritis - even haemorrhagic • Leaves present in rumen.

HISTOPATHOLOGY: In more chronic cases small foci of degeneration of cardiac musculature are seen occasionally.

TREATMENT: • Activated charcoal is very effective. • Dose 2g/kg. • Large dose is essential. • Adsorption and fixation of excess in rumen. • Even retro-diffusion back from plasma. • Minimize stress to prevent catecholamine release. Additional treatment for valuable animals: 1. Lignocaine. 2. ß-blocking agents 3. ACP: Tranquillizer (multipotent blocker) 4. Atropine (if AV-block is present).