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Cestrum Laevigatum
Description
It is a much-branched shrub or tree, growing 6-15 m high in coastal regions, but inland, in areas like the Free State and the Mpumalanga provinces of South Africa, it usually attains a height of 1-2 m. The dark to light-green leaves are about 50 mm wide and are easily bruised, emitting an unpleasant pungent odour. The small, greenish-yellow, tubular, sweet smelling flowers, 5-25 mm long, are borne in clusters mostly at the tips of branches. Later greenish berries, (10 mmX5mm), develop turning deep purple-black as they ripen. The plant usually bears its flowers and berries during June and July, the winter months
Distribution:
Cestrum laevigatum seems to occur over a large part of eastern South Africa. Cestrum spp. are native to South America and were introduced into southern Africa as evergreen ornamental shrubs, hedges and sometimes as windbreaks. They are now troublesome weeds.
Conditions of poisoning:
In South Africa, field outbreaks of Cestrum poisoning have been reported only in cattle. Cattle graze less selectively than other species and will eat the plant readily, especially during droughts and winter, a time when grazing is scarce..
Control
Poisoning can best be prevented by keeping cattle away from areas where the plant grows, especially during the months of June and July when it is most toxic.
Toxic principle
Type of toxin: Diterpenoid. According to Steyn (3) Wehmer extracted a saponin and cestrumid. Others isolated two substances, gitogenin and digitogenin. (The toxic principles of Cestrum parqui have been identified as the kaurene glycosides. Parquin an carboxy- parquin structurally closely related to atractyloside and carboxyatractyloside (the major toxin in Xanthium strumarium) and atractyloside in having a different pyranose ring and additional y-lactone).
Clinical signs
The principle clinical signs include salivation, lacrimation, sunken and staring eyes, arched back, signs of abdominal pain (restlessness, grinding of the teeth, groaning, kicking at abdomen, etc.), weakness, muscle tremors, staggering gait, incoordination, aggression, constipation, frequent urination and icterus. The course is often rapid, and some animals are found dead. The most macroscopical lesions are found in the liver, which is as a rule enlarged and friable, orange-brown in colour, with congested patches scattered throughout the parenchyma. The gall-bladder wall is often oedematous and may contain haemorrhages. Other less specific changes include cyanosis, oedema of the lungs, effusion of the body cavities, enterorrhagia, congestion and oedema of the abomasum folds, petechiae and ecchymoses on serosal surfaces, as well as subcutaneously, intermuscularly and in the epi- and endocardium. Congestion of the meninges and brain, spongy changes in the cerebral white matter, and icterus have also been reported. Sometimes the rectum contains dry feacal balls covered with a bloody mucus.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Plant Poisonings and mycotoxicoses of livestock in Southern Africa / T.S. Kellerman, J.A.W. Coetzer, T.W. Naude, C.J. Botha. Oxford University Press, c2005.

Poisonous plants of South Africa / Ben-Erik van Wyk, Fanie van Heerden, Bosch van Oudtshoorn. Briza, 2002.

The Toxicology of plants in South Africa /D.G.Steyn. Central News Agency, 1934.

Experimentally-induced Cestrum laevigatum (Schlechtd.) poisoning in sheep.
Lugt, J. J. van der ; Nel, P. W. ; Kitching, J. P. ;
Onderstepoort Journal of Veterinary Research. 1992, vol 59(2): 135-144

Lugt, J. J. van der ; Nel, P. W. ; Kitching, J. P.The pathology of Cestrum laevigatum (Schlechtd.) poisoning in cattle. Onderstepoort Journal of Veterinary Research. 1991, vol 58(3): 211-221

Thorburn, J. A. Chase Valley disease. Cestrum laevigatum Schlecht, its toxic effects on ruminants. Onderstepoort J. Vet. Sci. and Animal Indust. 1934, vol 2: 667-677

Steyn, D. G. Investigations into the toxicity of known and unknown poisonous plants in the Union of South Africa. 18th Rep. Director Vet. Services and Animal Indust., Union S. Africa. 1932: 871-891

The Weeds Eradication Section. The inkberry plant. A description, with special reference to its toxicity. Fmg. S. Afr. 1939, vol 14: 352-4

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Cotyledon spp
Description
Cotyledon orbiculata is a succulent shrub with woody branches and thick fleshy leaves of variable shape. They are bright green to grey, often with reddish margin and usually covered with a waxy layer on the surface. Attractive red to orange, tubular pendulous flowers are borne on a long stalk.Cotyledon barbeyi, is very similar looking but non-glaucous.
Distribution:
Cotyledon orbiculatais widely distributed over practically the whole of South Africa. Usually found on exposed rocky slopes. Cotyledon barbeyi, very similar looking but non-glaucous is found in the northern bushveld.
Conditions of poisoning:
Intoxication occurs especially in times of drought. Stock of all ages are affected but the young, probably because they graze with less discernment, is more prone. Toxicity of plants vary within and between localities and within seasons. Environmental factors such as soil types can also influecence toxicity e.g.C. orbiculata is more toxic on sandy soils than on black clay.
Toxic principle
In 1926 cotyledontoxin, which acted on the nervous sytem was extracted. Ten years later a substance with the digitalis-like pharmacological properties was found. Years later this digitalis-like substance proved to be the principle toxins. Convincing evidence exists that C. orbiculata can cause acute intoxication and Krimpsiekte. Strong indications exsist that the toxic principle has a cumulative effect.
Clinical signs
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

Botha, C. J. ; Lugt, J. J. van der ; Erasmus, G. L. ; Kellerman, T. S. ; Schultz, R. A. ; Vleggaar, R. ; . Krimpsiekte, a paretic condition of small stock poisoned by bufadienolide-containing plants of the Crassulaceae in South Africa. In Toxic plants and other natural toxicants by Garland, T. ; Barr, A. C. ; (eds.). 1998. p. 407-412

Tustin, R. C. ; Thornton, D. J. ; Kleu, C. B. . An outbreak of Cotyledon orbiculata L. poisoning in a flock of Angora goat rams. Journal of the South African Veterinary Association. 1984, 55 (4) : 181-184

Naude, T. W. ; Schultz, R. A. Studies on South African cardiac glycosides. II. Observations on the clinical and haemodynamic effects of cotyledoside. Onderstepoort Journal of Veterinary Research. 1982, 49 (4): 247-254

Steyn, D. G . A study of the factors concerned in the determination of the toxicity of Cotyledon orbiculata L . 18th Rep. Director Vet. Services and Animal Ind., Union 8. Africa. 1932, p. 899-938

Steyn, D.G. Investigations into the toxicity of known and unknown poisonous plants in the Union of South Africa. 18th Rep. Director Vet. Services and Animal Indust., Union S. Africa. 1932, p. 871-891

Terblanche, M. ; Adelaar, T. F. A note on the toxicity of Cotyledon orbiculata L.. Journal of the South African Veterinary Association 1965, 36 : 555-559

van der Walt, S. J. ; Steyn, D. G Recent investigations into the toxicity of known and unknown poisonous plants in the Union of South Africa, IX. Onderstepoort Journal of Veterinary Science, 1939-40, 12: 335-366

UNION OF SOUTH AFRICA, Department of Agriculture . Lectures and Discussions at the Meat Production Course held at Pretoria, Jan. 9th-17th. Lectures and Discussions at the Meat Production Course held at Pretoria, Jan. 9th-17th.. 1933, 165 pp.

Howes, F. N. Variability in stock-poison plants. Kew Bull. 1933, 7: 305-21

Curson, H. H. Some Little Known South African Poisonous Plants and their effects upon Stock. M.S. Thesis for the Fellowship Diploma R.C.V.S. 1925

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Datura spp.
Description
It grows to a height of 1,5 m. It is a robust annual plant with thick stems, large irregularly lobed, hairless leaves and large attractive white or pale purple flowers. Distinctive fruits are thorny capsules that split open to release numerous small kidney-shaped blank seeds
Distribution:
This cosmopolitan pioneer, is a common annual weed in southern Africa. Both species are widely distributed in South Africa.
Conditions of poisoning:
Datura plants often grow on lands where their ripe seeds are mechanically harvested with grain from which they cannot easily be separated. In humans seeds may be accidentally eaten by small children or deliberately as a dangerous prank amongst schoolchildren., sometimes with fatal results. Poisoning may also result from the seeds contaminating grain and flour, or from leaves accidentally collected as wild spinach (marog).
Control
Humans, unlike livestock, are highly susceptible to atropine poisoning, the therapeutic dose in humans being 1 mg for an adult. The maximum permissible contamination of products for human consumption, therefore, is one Datura seed/10 kg maize kernels, five Datura seeds/400g soya beans and three Datura seeds/400g shelled ground nuts. As a precaution, contaminated feed should be either diluted with wholesome material or tested for toxicity in a few inferior animals before being fed on a large scale.
Toxic principle
Tropane alkaloid. The plant contains the parasympatholytic alkaloids, atropine, hyoscine and hyoscyamine, all of which exert mainly an antimuscarinic effect. High doses block transmission of autonomic impulses at ganglia and neuromuscular junctions.
Clinical signs
Datura species are not regarded as being important toxic plant in South Africa. Horses are nevertheless extremely susceptible to this poisoning and several outbreak of impaction colic induced by the plant have been reported. An outbreak of Datura poisoning also occurred in cattle kept in a large camp bare of vegetation save for a large heap of dry Datura plants. Poisoning of ostrich poults is more common. Clinical signs include mydriasis and cycloplegia, dryness of mouth, colic, tremors, convulsions, respiratory paralysis and coma. Excessive doses of atropine may cause mania and excitement in animals. In horses, gastric dilatation followed by rupture and unresponsive paralytic ileus have been described. Livestock are generally more refractory to atropine poisoning than humans.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Plant Poisonings and mycotoxicoses of livestock in Southern Africa / T.S. Kellerman, J.A.W. Coetzer, T.W. Naude, C.J. Botha. Oxford University Press, c2005.

Poisonous plants of South Africa / Ben-Erik van Wyk, Fanie van Heerden, Bosch van Oudtshoorn. Briza, 2002.

The Toxicology of plants in South Africa /D.G.Steyn. Central News Agency, 1934.

Gerber, R. ; Naudé, T. W. ; Kock, S. S. de. Confirmed Datura poisoning in a horse most probably due to D. ferox in contaminated tef hay. Journal of the South African Veterinary Association. 2006 , 77(2): 85-89

Naudé, T. W. ; Gerber, R. ; Smith, R. J. ; Botha, C. J. Datura contamination of hay as the suspected cause of an extensive outbreak of impaction colic in horses. Journal of the South African Veterinary Association. 2005, 76(2): 107-112

Schulman, M. L. ; Bolton, L. A. Datura seed intoxication in two horses. Journal of the South African Veterinary Association. 1998 , 69 (1): 27-29

Coetzer, J. A. W. ; Kellerman, T. S. ; Naudé, T. W. Neurotoxicoses of livestock caused by plants and fungi in southern Africa. Technical Communication, Department of Agriculture, South Africa. 1985, No.199. 38pp.

Steyn, D. G. Poisoning of Human Beings by Weeds Contained in Cereals (Bread Poisoning) and Senecio Poisoning in Stock. J. Roy. San. Inst. . 1936, 56: 760-68

Beyers, J. M. Notes on Epidemic Poisoning by Datura Stramonium Journal of the Medical Association of South Africa. 1930, 4 : 102

Steyn,, Douw G. The Poisoning of Human Beings by Wild Plants, Ornamental Plants and Domestic Poisons. Public Health. 1941, 5 (4): 13-14; 16; 18; 20-23; 25-6

Watt, J. M. Plants and poisoning in man, with a short account of plant allergy. South African Journal of Science. 1936, 33 : 702-707

Schäle, E. The Ostrich as an Economic Animal. Der Strauss als Wirtschaftstier. Z. Tierz. Zucht Biol.. 1942, 52: 263-279

Watt, J. M. ; Breyer-Brandwijk, Maria G. The Medicinal and Poisonous Plants of Southern Africa. 1932. 314 pp.

Stent, S.M. Some Poisonous Plants of Southern Rhodesia. Rhod. Agric. J. 1931, 28: 811-821

Steyn, D. G. ; Walt, S. J. van der. Recent investigations into the toxicity of known and unknown poisonous plants in the Union of South Africa. XI. Onderstepoort Journal of Veterinary Science. 1941, 16: 121-47

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Dichapetalum cymosum
Description
It is an enormous woody plant that grows underground except for the numerous branch tips that emerge above the ground. The leaves are alternate, simple, oblong, bright green on both surfaces, with the secondary veins forming loops near the leaf margin, producing an arched effect. At the base of each leaf stalk are two very small stipules. Clusters of white flowers are produced in early spring. On rare occasions orange fruits are formed. Some of the African Dichapetalum spp. are trees
Distribution:
This plant is a common cause of serious livestock losses in South Africa, Botswana, Namibia and Zimbabwe. It occurs from Gauteng northwards and westwards, Limpopo, North-West and Mpumalanga provinces, with an isolated area in the extreme north of KwaZulu-Natal. Plants are usually found on northern slopes or sandy flats.
Conditions of poisoning:
Because it is such a deep-rooted plant, it sprouts at a time when no other green pasture is available. Young, newly emerged shoots are particularly toxic.
Control
Attempts to get rid of gifblaar by digging it out are seldom successful and often serve only to aggravate the situation.. Mechanical eradication is not practical. Poisoning can be avoided by fencing off gifblaar patches, as the plant hardly spread at all. Few seeds are produced, and many of these are destroyed by insects. Unfenced pastures should be avoided, especially in spring and autumn, when the plants sprout. Graze these pastures in mid-summer, when the pastures are lush, or in winter after frost, when the leaves have dropped off.
Toxic principle
Monofluoacetic acid. Fluoroacetic acid is relatively harmless but is converted in the body of the animal to highly toxic fluorocitrate
Clinical signs
Monofluoacetic acid interferes with the metabolism of acetic acid in the Krebs cycle and cause a fatal loss of cellular respiration. It mimics the action of acetic acid, so that fluorocitric acid is formed instead of citric acid. Fluorocitric acid inhibits the activity of aconitase enzymes. The lethal oral dose of monofluroacetate is less that 0,5 mg/kg bodyweight in most animals. As little as 20g of fresh leaves may kill a sheep. Ruminants typically die of heats failure within 24 hours of ingesting the plants without showing any symptoms (sudden death).
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

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Drimia spp.
Description
The vernacular name slangkop (snake head) is used for some Drimia spp. as well as certain other members of the Hyacinthaceae. The name describes the snake-like appearance of the newly emerged flower heads. Drimia spp. are typical bulbous plants with a single flowering spike that emerges before the leaves in spring. The arial parts die off in winter, but the perennial bulbs survive. Each flower is subtended at the junction of the flower and inflorescence stalks by a characteristic spurred bract. The spurs may be inconspicuous.
Distribution:
Conditions of poisoning:
Because they are bulbous the various Drimia spp. are less dependent on rainfall and can draw on their own reserves to sprout in spring before it rains. In drought years they might be the only greenery for stock to eat on the barren veld. The inflorescences and palatable young leaves are the most dangerous as mature plants are less often eaten. After frost, Drimia spp.-infested veld is said to be relatively safe.
Control
Stock that grow up on Drimia spp. veld learn to avoid the plants.
Toxic principle
The active principle of D. sanguinea is a glycosidal substance with a digitalis-like action. A cardiac glycoside, transvaalin, was extracted from D. sanguinea bulbs. Hydrolysis of transvaalin yielded scillaridin A, and scillabiose, which indicated that transvaalin was either isomeric with scillaren A or a stable complex of scillaren A and scilliroside, a well-known rodenticide. The toxic principles in D.physodes are physodine A and B. Rubellin, a cardiac glycoside was isolated from D.calarata. Rubellin apparently acts as a cardiac poison in rats, while transvaalin acts on the central nervous system. A bufadienolide, altoside, has also been iaolated from D. altissima. D. capensis exhibits cardiac glycoside activity.
Clinical signs
In rare instances of krimpsiekte-like signs vide infra have been reported in stock poisoned by Drimia spp. in the field. The clinical signs appeared after about 17 – 24 hours, and sheep died two to three days after poisoning. Heart failure and signs of haematuria and icterus have been reported.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

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Fadogia homblei
Description
The plant is a perennial herb or shrublet with numerus erect stems of up to 50cm high, arising from the thick, woody rizome below the ground. Above-ground parts die back in winter. The leaves are very characteristic – they are borne in groups of 3 – 5 at each node; the upper surfaces are bright shining and dark green, while the lower surfaces are silvery white. Small yellow, fragrant flowers are produced in clusters at the nodes followed by round, green fruit that turn black when they ripen. These fruits are edible and resemble engorged ticks, hence the Afrikaans vernacular name, bosluisbessie. No case of human poisoning is known but the plant is potentially lethal to farm animals. Causes Gousiekte in stock.
Distribution:
Occur in the northern parts of South Africa. Limpopo Province.Also common on white, grey or pale red soils in northern Gauteng and the adjoining areas of neighbouring provinces.Also found on mountain ranges of the Magalisberg and the eastern escarpment streching from Swaziland to Central Africa
Conditions of poisoning:
Gousiekte is a fatal heart disease of domestic ruminants caused by various plants of the coffee family (Rubiaceae) Death typically occurs after a long latent period of four to eight weeks after the plants were eaten. A single dose can occasionally be fatal, but relatively large quantities of plant material have to be ingested. Animals are usually affected in the early summer when grazing is scarce. Various factors are known to influence the outbreak of gousiekte, including climatic conditions, variation in susceptibility amongst animals and variation in toxicity of the plants.
Control
Repeated ploughing on arable land will led to eradication. Continuous digging will eventually destroy the plants on pastures, but is costly. Gousiekte is best controlled by good pasture management. Herbicides that contain fenac or picloram have been shown to control gousiektebossie without damaging the surrounding grass cover. One of the difficulties in controlling gousiekte is that affected animals cannot be recognised during the latency. It is important to identify these covertly affected animals so that they can be slaughtered, at least saving the carcass
Toxic principle
Polyamine.
Clinical signs
Animals characteristically drop dead without showing any warning signs, often after exercise. The condition ascribed to acute heart failure and recovery is rare. It is interesting that death occurs several weeks after ingestion of the toxic plant material. Recovery is rare.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

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Geigeriaspp.
Description
G.ornativa is an annual or short-lived perenial with characteristic tufts of slender, sparsely hairy leaves and small yellow flower heads borne half hidden amongst the leaves. G.aspera, is more toxic butt less abundant. It is a rounded shrublet with smaller ribbon-like leaves and larger flowers. The daisy-like flowerheads persists for many months until the seeds are shed. The seeds are distributed by wind and water, and in the droppings of animals. G.burkei is a branched shrublet with narrow leaves.
Distribution:
G.ornativa is found in the drier southern and western parts of South Africa G.aspera favours the loam and clay soils often near swamps or on river banks and open savannah where rainfall is high.
Conditions of poisoning:
The first signs of vermeersiekte may appear a few days after commencement of grazing on Geigeria. Affected sheep lag behind the flock, tire easily, develop a stiff gait, and frequently lie down. Eventually they become too weak to support themselves. Paralysis may set in after a few days.
Control
The animals usually recovers if the are removed from the poisonous grazing at an early stage of intoxication. Some people believe the solution to the vermeersiekte problem lies not in therapy but in improved pasture management, since outbreaks of the disease are virtually confined to veld denuded of grass cover by overgrazing, trampling, injudicious burning and poor management. Subdivision of farms into uneconomic units has exacerbated the situation. Eradication of the plant should preferably be done in the pre-flowering stage before the seeds are formed. Alternatively, a short-term rotational grazing system can be practiced in which a flock is kept approximately two week “on” and two weeks “off” an infested pasture. The aim is to move the sheep from the Geigeria before signs of vermeersiekte can appear and allowing them to “recover” from possible sub clinical intoxication before returning. The prospect of eradicating vermeerbos by means other that high pressure grazing with sheep is not very promising. Pulling plants out by hand is costly. Also the cleared areas quickly become re-infested by the seeds that have lain dormant on the ground for years.
Toxic principle
Sesquiterpenoid lactone. The toxicity of G.aspera is ascribed to vermeeric acid. Other sesquiter-penoid lactones are known from Geigeria species, such as geigerin, geigerinin,griesenin and dihydrogriesenin,
Clinical signs
Vermeersiekte is a condition mostly of sheep and goats caused by Geigeria spp., characterised by regurgitation of ruminal contents through the nose and mouth so that the lips are stained green, stiffness, paresis and paralysis. It is one of the most important plant poisonings of sheep on the subcontinent. In South Africa alone accounting for 13% of all stock deaths from plant poisoning and mycotoxicoses. Goats develop signs similar to those of sheep, but they are apparently more susceptible to the paralytic form of the disease. The causes of death in vermeersiekte are listed as asphyxiation as a result of choking on inhaled ingesta or paralysis of the respiratory centre, exhaustion from “vomiting” and purgation, heart failure, and acute or chronic foreign body pneumonia. Lesions in randomly distributed myocytes or groups of muscle fibres and myocardium. Cattle ingesting Geigeria spp. primarily develop stiffness. The signs often start with salivation followed by a stiff gait, sometimes accompanied by paralysis and a conspicuous loss of condition. Although they seldom regurgitate.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

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Gnidia spp
Description
Gnidia Spp. are erect shrublets with small leaves arranged along thin stems. Small, tubular yellow flowers are arrange in sparse to dense heads. In G. kraussiana, the flowering stalks are leafless below the heads and the stems and leaves are hairy. G. burchellii is a woody shrub with leaves congested towards the branch ends. G. polycephala has numerous, erect branches that are leafless except when young, and few-flowered, hairy heads, each with a few large, papery bracts below the flowers.
Distribution:
G. kraussiana occurs in the northern and eastern parts of South Africa. G. polycephala mainly in Limpopo Province and G. burchellii grows in stony and sandy soil on hill and valley slopes in trampled areas in the south-western Mpumalanga, north-eastern Free State, north-western KwaZulu-Natal and the Northern Cape Province.
Conditions of poisoning:
Numerous fatalities in both human and livestock are caused by Gnidia spp. in various parts of Africa, including South Africa. G. kraussiana is a traditional medicine and an overdose may be fatal. The plant has been used as fish poison and arrow poison. G. burchellii outbreaks of poisoning have been reported only in sheep. G. polycephala poisoning was reported in sheep and cattle, eating the plant in times of adversity, like winter, when flowering. The toxicity is reputed to be the highest in the flowering stage.
Control
When milling the plant, contact with the dust must be avoided and respirators should be worn.
Toxic principle
Diterpenoid. The toxic principle of G. burchellii is a 12-hydroxy analogue (C27H30O9) of daphnetoxin 8, 9, 37, a phorbol-derived diterpenoid ester.
Clinical signs
Gnidia poisoning in livestock results in severe diarrhoea, weakness, fever and a rapid, weak pulse. Lesions have been found in sheep. These include myocardial necrosis, pulmonary oedema and emphysema and lymphoid atrophy. When large quantities are ingested, death may be sudden, without any obvious symptoms. In humans powered material of gnidia spp. causes irritation of the nose and throat. Coughing and sneezing, followed by headache and nausea. Gnidia diterpenoids have anti tumour and anti leukaemic activity.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

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Kalanchoe spp.
Description
K. rotundifolia is a succulent perennial herb with erect, unbranched stems and rounded to oblong fleshy leaves arranged in opposite pairs. The tubular, orange and red flowers are borne in many-flowered clusters on a long stalk. Kalanchoe species can easily be distinguished from other genera by the four petals and four fruit segments. K. lanceolata an erect annual or short-lived perennial with bright green, oblong, succulent leaves and yellow to orange flowers. K thyrsiflora , K. lanceolata and K. rotundifolia is all known to be poisonous.
Distribution:
K. rotundifolia is widely distributed in the eastern parts of South Africa while K. lanceolata is found north of the Free State up into tropical Africa from Ghana in the west to Ethiopia in the east.
Conditions of poisoning:
Poisoning occurs mainly in spring and summer, usually during droughts when grazing become scarse. The plants are succulent in the dry season and are eaten by livestock when other grazing is unpalatable. All animals, including horses, dogs and chickens are susceptible, but sheep and goats are more commonly effected.
Control
Activated charcoal is the most effective treatment of plant-induced cardiac glycoside poisoning of livestock in South Africa. The charcoal is dosed to the animals as soon as the first clinical signs appear. Although activated charcoal is an extremely effective treatment, it must be borne in mind that the stress of handling animals with hearts about to fibrillate can be fatal. Prior treatment with anti-arrhythmic drugs (to reduce the risk of fibrillation) and atropine ( to prevent vagotonic conduction disturbances) seems to be strongly indicated. In addition to activated coal, other therapies might be considered, such as systemic alkalinizers to combat the metabolic acidosis and measures to normalize hyperkalaemia.
Toxic principle
Contains cumulative neurotoxic bufadienolodes that cause Krimpsiekte. Hellebrigenin acetate, designated lanceatoxin A and lanceatoxin B were isolated and chatacterised from K. lanceolata.
Clinical signs
Krimpsiekte is an intoxication of livestock that effects the nervous and muscular systems, usually with fatal results. It is one of the major causes of stock losses in South Africa. The meat of poisoned animals may cause secondary poisoning of dogs and even humans. Two types of krimpsiekte can be distinguished, an acute (opblaas) krimpsiekte resulting in sudden death, or chronic (dun) krimpsiekte that develop gradually. Symptoms of krimpsiekte poisoning are very different from those normally seen with cardiac glycoside poisoning: exhaustion, paralysis of the head and neck, convulsions, respiratory paralysis and finally death. Poisoned animals may sometimes lie paralysed but fully conscious on their sides for several weeks before they die. Animals suffering from typical krimpsiekte lag behind the flock, tire easily, walk with the head dangling loosely , and often lie down, usually with the neck stretched flat on the ground. Many will assume a characteristic posture, with feet together, back arched, head down and neck sometimes twisted to one side (torticollis) . The name krimpsiekte, or shrinking disease, is derived from this characteristic stance.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

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Lantana spp.
Description
Lantana Camara is an exotic ornamental shrub that has become a noxious weed, particularly in the moist eastern parts of the country. The small trumpet-shaped, yellow to orange, red and mauve to white flowers are borne in dense terminal clusters, usually with flowers of two different colours occurring in one cluster. The fruits are small black berries, much relished by birds that spread the seeds. It is a declared weed in terms of the Conservation of Agricultural Resources Act (No 43 of 1983). Lantana rugosais an indigenous specie with few, small light purple flowers and darker purple fruits.
Distribution:
Lantana camara is a noxious weed of tropical American origin that was originally imported as an ornamental garden shrub. Birds eat the berries and spread the seeds, so that the plant has escaped from gardens and is now widely distributed in South Africa.
Conditions of poisoning:
Lantana camara poisoning is probably the second most important hepatotoxicosis of cattle in South Africa. This photosensitisation is held responsible for 3% of the national stock deaths from all plant poisonings and mycotoxicoses. Lantana poisoning usually occurs only in cattle, but one outbreak in goats has been reported.
Control
Lantana can be controlled by manual/mechanical or chemical means. Long term biological control is hampered by a predilection for certain forms by host-specific insects, and chemical control by variable response to herbicides. It also may kill other plant species. Uprooting plants may work, but can lead to erosion and is labour intensive as well as costly. What ever method is used , flow-up is essential.
Toxic principle
Triterpenoid. Being poorly assimilated, the triterpenes must continuously pass through the gut for relatively long periods to induce and maintain intoxication. Pentacyclic triterpenes are absorb from all areas of the gastrointestinal tract, especially the small intestine, and transported via the portal vein to the liver. Here they are metabolized to more polar compounds, which are excreted in the bile, injuring the canaliculi. This damage, which includes loss of microvilla and collapse of the canaliculi, is held responsible for the cholestasis.
Clinical signs
Photosensitivity resulting from damage primarily to the liver parenchyma. Clinical signs include anorexia, severe depression, icterus and photosensitivity. Clinical pathological changes consistent with hepatosis and nephrosis have been recorded. The macroscopical lesions are typical of hepatogenous photosensitivity, namely, icterus, photodermatitis, yellow to orange-brown discolouration and swelling of the liver, impaction of the caecum and colon, and nephrosis. The gall-bladder may be oedematous and distended with straw-coloured to dark-green bile. Histopathological changes involving the hepatocytes include swelling, distinct delineation of cell membranes, diffuse cloudy swelling and hydropic degeneration, and sometimes also mild to moderate fatty changes. Intracytoplasmic eosinophilic globules often accompany the above changes.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

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Moraea spp.
Description
This bulbous plant has three to five long, strap-shaped, flat leaves and attractive iris-like flowers borne on a branched flowering stem. The colours of the flowers vary from yellow, mauve, pink, pale blue depending on the specie.
Distribution:
M. polystachya is widely distributed in the central interior of South Africa and northwards into Namibia. It often forms dense stands, especially in overgrazed areas. Several other species occur in the western and eastern parts of South Africa.M. carsonii is found in grasslandsin Zimbabwe and also in Botswana.M.bipartita L. occurs in the Eastern and Western Cape provinces' coastal belt and M. miniata grows under a variety of soil conditions in Western and Northern Cape provinces.
Conditions of poisoning:
Moraea spp. are important causes of tulp poisoning, mostly in cattle. Stock losses usually occur during the winter months, when the leaves emerge from the bulbs at a time when other grazing is scarce. Drying do not destroy the toxins, so that hay may also cause fatalities. Toxicity varies according to growth stage, locality and climate.
Control
Newly introduced or hungry animals are especially at risk. Animals that grow up on tulp-infested veld learn to avoid it.
Toxic principle
Cardiac glycoside (bufadienolide). All species of Moraea found in South Africa should be regarded as poisonous.
Clinical signs
Symptoms typical of cardiac glycosides, include bloat, nervousness, immobility, and a weak heart. Treatment with activated charcoal can be effective. Hungry cattle from a non-tulp area develops signs of poisoning within 24 hours of being driven into tulp-infested pasture. Death generally intervenes 24-28 hours after ingestion of tulp plants and non-fatally poisoned animals usually recovers within three to four days.
References
Vahrmeijer, J. Poisonous plants of Southern Africa that cause stock losses. Tafelberg Publishers,Cape Town. 1981.

Kellerman,T.S.; Coetzer, J.A.W.; Naude,T.W.; Botha, C.J. Plant Poisonings and mycotoxicoses of livestock in Southern Africa. 2nd ed. Oxford University Press, Cape Town. 2005.

van Wyk,Ben-Erik; van Heerden, Fanie; van Oudtshoorn, Bosch. Poisonous plants of South Africa Briza, Pretoria. 2002.

Steyn, D.G.The Toxicology of plants in South Africa Central News Agency, 1934.

Back to Alphabetical list