T. laxa is mainly found in grassveld areas, while T. divaricata grows in the sandy soil and dunes of the south-western areas of the Cape Province.
General: These are perennial plants with underground rhizomes.
Leaves: Numerous soft succulent leaves arranged in rosettes
Flowers: Large, branched upright inflorescences with small white flowers.
T. laxa is a tumbleweed.
•The plants are palatable early in the growing season and outbreaks occur in the overgrazed areas during the dry months.
• The incidence of the disease ceases soon after the onset of good rains and improvement of pastures.
Central nervous system.
•Initially the animals move with difficulty, show over-knuckling, hypersensitivity and tremor.
•Progressive ascending paresis and paralysis follow and animals remain in sternal recumbency.
•Affected animals starve or die of exposure 1 - 3 months later.
•In horses, the signs may disappear after light exercise, though the animals tire easily and show dyspnoea.
•Usually no macroscopical changes present
•Microscopically a khakhi-brown pigment is visible in the cytoplasm of the larger neurones of the brain, spinal cord and ganglia.
With proper feeding or with improved grazing, complete recovery from the early signs may occur after six months, but in some cases only partial recovery occurs and the animal retains a paretic limb.
Colour photos. Final web-ready size: JPEG. Photo 1: 89.9 kb, 300 ppi; Photo 2: 22 kb, 72 ppi; Photo 3: 19.4 kb, 72 ppi; Photo 4: 13 kb, 72 ppi; Photo 5: 12.8 kb, 72 ppi. Original TIFF file housed at the Dept. of Paraclinical Sciences, Section Pharmacology and Toxicology, University of Pretoria.