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).
