DISTRIBUTION:
• Bushveld and rocky ridges, mainly in sandy soils (white, grey or pale-red soils).
• To the North and East of Pretoria, also common in parts of Gauteng, Limpopo and Swaziland.
BOTANICAL DESCRIPTION:
General: A perennial herbaceous shrublet with many erect, unbranched annual stems about 50 cm high. These arise from a thickened, erect, underground stem and die off in winter.
Leaves: The stalkless, shiny green leaves are greyish white felted below. Produced at approximately evenly spaced intervals up the stem in whorls of 3 to 5.
Flowers: Star-shaped, yellowish-green flowers with 5 petals clustered in the axils of the leaves. Fragrant. Spring.
Fruit: Fleshy round berries which are green at first, shiny black when ripe. A single seed in each of its three chambers.
TOXIC PRINCIPLE:
• A water-soluble polyamine called pavettamine.
• Has a delayed effect on the heart.
• This toxin is pH-labile and will be destroyed at pH < 2,5.
• This could explain why only ruminants are susceptible (Rumen pH = 6,8).
• Only very young sprouting plants are toxic.
SYNDROME:
Gousiekte
SYSTEMS AFFECTED:
Cardiovascular system.
CLINICAL SIGNS:
Mechanism of action:
The toxin inhibits synthesis of new myocardial protein, especially myosin.
• After ingestion of a lethal dose of the plants, a characteristic latent period of
6 - 8 weeks of apparent normality follows before the animals suddenly die.
• The majority of animals typically drop dead, usually after being frightened, handled
or chased, although some may die without any stressful event occurring.
• In a few cases congestive heart failure such as weakness, panting, respiratory
distress and anasarca, particularly of the head, are present.
NECROPSY:
Macroscopical findings:
Signs of heart failure:
• Lung oedema
• Hydrothorax
• Hydropericardium although some cases may not show any macroscopic
changes.
Irregular areas of pallor (greyish areas) may be seen, particularly in the endocardium.
HISTOPATHOLOGY:
• A multifocal to diffuse subendocardial replacement fibrosis accompanied by a
round cell infiltration, predominantly in the apex, left ventricular wall and inter-
ventricular septum.
• Focal to diffuse degeneration and/or necrosis of myofibres.
• Hypertrophy or even atrophy of myocardial fibres.
TREATMENT:
•No specific treatment, only symptomatic and supportive
•Avoid unnecessary stressful situations
