Evaluation of activated charcoal as treatment for Yellow tulp (Moraea pallida) poisoning in cattle.

The efficacy of activated charcoal as a treatment for cattle (n = 57) poisoned by Yellow tulp (Moraea pallida) was investigated. Treatment with activated charcoal resulted in full recovery, irrespective of the degree of posterior paresis, provided that this clinical sign did not develop within the first 12 hours after initial exposure to Yellow tulp-infested grazing. For instance, despite treatment, 1 of 7 cattle succumbed after manifesting mild posterior paresis 6 to 8 h after initial exposure and 3 of 3 treated cattle died after developing severe posterior paresis within 6 to 12 h.

Changes in sheep oesophageal diameter and function during Geigeria ornativa (vermeerbos) poisoning and subsequent recovery.

Changes in the oesophageal diameter and function together with changes in body weight, feed intake and the cardiac pulmonary flow index were investigated during experimentally induced poisoning with Geigeria ornativa and subsequent recovery. This was performed under varying conditions for individual sheep. Results showed an increase in the oesophageal diameter index (ODI) during vermeersiekte, accompanied with a decrease in oesophageal function (OF). Cessation of G. ornativa intake resulted in a considerable although incomplete recovery of the ODI. Recovery of the OF for the different sheep, however, varied between 0 and 100%. Detrimental changes in the oesophageal diameter and function were also measured in sheep receiving only subclinical doses of G. ornativa. Decreases in body weight and feed intake commenced 1 to 3 weeks before the onset of vermeersiekte, while indications of a decline in these 2 parameters were also noticed with ingestion of subclinical amounts of G. ornativa. An increase in the cardiac pulmonary flow index (CPFI) to a value indicating the onset of heart failure was found in 1 of the sheep showing clinical signs of vermeersiekte. The CPFI returned to normal after termination of G. ornativa intake.

Conditioned feed aversion as a means to prevent tulp (Homeria pallida) poisoning in cattle.

Conditioned feed aversion was investigated as a means to prevent tulp (Homeria pallida) poisoning in cattle on tulp-infested grazing. Aversion treatment with a combination of epoxyscillirosidin and lithium chloride together with a tulp-hexane extract, which served as identification factor for tulp, resulted in a significantly lower (P < 0.001) proportion of severe tulp poisoning. In a first trial where 21 averted and 21 non-averted control cattle were exposed to a tulp-infested grass pasture, only two of the averted cattle were severely poisoned compared to 13 of the non-averted control cattle. In a second trial, with cattle being exposed to a pure stand of tulp supplemented with maize residues, only two of 21 averted cattle were severely poisoned compared to 14 of 21 non-averted control cattle. Occurrence of mild tulp poisoning, however, did not differ much between averted and non-averted control cattle. The results show that conditioned feed aversion effectively restricted severe poisoning in cattle on tulp-infested grazing.

Suspected nitrite poisoning in pigs caused by Capsella bursa-pastoris (L.) Medik. ('herderstassie', shepherd's purse).

Nitrite poisoning in pigs was suspected when 4 of 18 pigs died in a piggery near Ellisras in the Northern Province. The pigs showed typical brownish discolouration of the blood at autopsy. It was established that they ingested vegetable tops and weeds from the adjacent garden as part of their daily ration. Of the available plants, only Capsella bursa-pastoris contained nitrites. The drinking water and some of the other plants tested positive for nitrates but not for nitrites. This is the first report of suspected nitrite poisoning in pigs caused by Capsella bursa-pastoris.

[Mechanism of spontaneous occurrence of tachycardia]. / Mécanismes de démarrage spontané des tachycardies.

Tachycardias arise from an arrhythmogenic substrate and a trigger factor, an extrasystole, the two factors being under the influence of the autonomic nervous system. The study of the mechanisms of spontaneous initiation of arrhythmias must, therefore, take these three factors and their interactions into account. The frequency dependency of an arrhythmia and the sensitivity of the substrate to the adrenergic system varies with time in a given subject and from one patient to another according to the presence and type of cardiac disease. The mode of initiation of most ventricular tachycardias and the therapeutic consequences may be understood: in some forms of cardiac disease, such as arrhythmogenic right ventricular dysplasia, the increase in heart rate which usually precedes sustained ventricular arrhythmias is only perceptible in mild or recent forms, unlike the more chronic dysplasias. This suggests that the arrhythmogenic substrate becomes more sensitive to catecholamines with time, and therefore requires smaller changes in sympathetic tone in order to be expressed (adrenergic paradox). Heart rate changes accompany modifications of sinus variability. Holter monitoring has shown, and this has been confirmed by recordings obtained from patients with implanted automatic defibrillators, that global sinus variability decreases before the initiation of a ventricular arrhythmia. Studies of the dynamics of ventricular repolarisation should also confirm the changes of QT frequency-dependency. The analysis of the initiation of arrhythmias would only have an academic interest if this was limited to a purely descriptive exercise. It is one of the best means of understanding arrhythmias and their therapeutic implications. The development of computerised methods of analysis of Holter monitoring should lead to further progress in this field.

Artificial transmission of Bolo disease in woolled sheep and attempted characterisation of the causative unclassified Corynebacterium sp.

Bacterial isolates (n = 38) previously cultured from sheep with Bolo disease were compared bacteriologically with known Corynebacterium spp. and Actinomyces spp. The isolates did not conform to any previously described species but closely resembled C. pseudodiptheriticum and C. urealyticum. More comprehensive tests are needed to classify this Corynebacterium sp. Bacterial cultures of this unclassified Corynebacterium sp. were used artificially to induce Bolo disease in Dohne Merino sheep (n = 20). Ten sheep were kept at Middelburg in the Cape Midlands (Northern Cape) under arid conditions and another 10 at Queenstown in the Eastern Cape in a more humid climate. Two suspensions containing 2.8 x 10(5) Corynebacterium sp. (inoculum A) and 2.8 x 10(9) Corynebacterium sp. (inoculum B) respectively were used to infect each sheep on 9 different sites on the skin. One sheep died during the course of the experiment. Corynebacterium sp. established itself on 81 out of 171 inoculation sites of the remaining sheep and caused typical lesions of Bolo disease, clinically and pathologically. Bolo disease lesions developed slowly over 175 days at Middelburg and 287 days at Queenstown. Weather conditions were unfavourable to the development of fleece-rot and mycotic dermatitis. No difference was seen in lesion development between rams and ewes or between sheep with 5 months' wool growth and those which were shorn before inoculation. More lesions developed with the higher concentration of inoculum B (49 sites positive) as compared to inoculum A (32 sites positive).

Experimental evidence that the active principle of the poisonous plant Thesium lineatum L.f. (Santalaceae) is a bufadienolide.

The toxicity of Thesium lineatum is confirmed in sheep. A toxic crystalline bufadienolide, with the suggested trivial name thesiuside, has been isolated from it. This is the first cardiac glycoside to be isolated from a member of the Santalaceae. The toxin appears to have no cumulative effect and the symptoms of intoxication and pathology in sheep are similar to that expected from acute cardiac glycoside intoxication.

An ovine hepatotoxicosis caused by the plant Hertia pallens (DC.) Kuntze (Asteraceae).

A field outbreak of Hertia pallens poisoning in sheep is described. The hepatotoxicity of the plant was experimentally demonstrated in 7 sheep which developed lesions that ranged from a diffuse degeneration to centrilobular necrosis. These lesions occasionally extended to the midzonal area of the lobules. In addition to a lung oedema, a diffuse mononuclear interstitial pneumonia was present in 3 of the sheep. Botanical, clinical and pathological data are given.

Valsiekte (falling disease): a nervous disorder in lambs suspected of being caused by the plant Chrysocoma tenuifolia.

A description is given of the clinical signs and pathological changes in 23 field cases of valsiekte from the Bethulie region of the Orange Free State, Republic of South Africa. The disease, which occurred almost exclusively in 2-4 month-old Dorper or Dorper cross-bred lambs, was characterized by protracted ataxia, paresis and high mortality. Microscopical changes were consistently found in the neurons and white matter along the entire length of the spinal cord, and rarely in the medulla oblongata. These changes included vacuolation and degeneration of neurons, mainly of the lateral and ventral horns in the spinal cord, and a status spongiosus which was most noticeable in the lateral and ventral tracts of the spinal cord. All affected lambs had access to the plant, Chrysocoma tenuifolia (bitterbos), but trials to reproduce the condition by dosing the plant, were not successful.

Ovine wet carcass syndrome induced by water deprivation and subsequent overhydration: preliminary findings.

Two groups of 25 one-year-old Dorper rams were deprived of water for 52 h and then allowed free access to water for the last 18 h before they were slaughtered. One of these groups received a maize-meal and bone-meal lick containing 28,5% salt (sodium chloride) during the last 18 h period. A control group of 20 sheep received water throughout the experiment. The salt group had an average intake of 4,5 liters of water per animal in the 18 h rehydration period while the other water deprived group drank about 3,8 liters of water per animal. After being slaughtered, all the sheep in the salt group had typically wet and glistening carcasses, 18 of the other water deprived group had wet carcasses while none in the control group were affected. These results seem to indicate that the wet carcass syndrome is caused by overhydration after a period of dehydration and that salt intake during rehydration can exacerbate the condition.

Krimpsiekte and acute cardiac glycoside poisoning in sheep caused by bufadienolides from the plant Kalanchoe lanceolata Forsk.

Three toxic bufadienolides , one characterized as hellibrigenin 3-acetate, have been isolated from Kalanchoe lanceolata Forsk. Typical signs of cardiac glycoside poisoning, involving the gastro-intestinal, neuromuscular and cardiovascular systems, could be induced by drenching the milled plant to sheep. Such signs could also be induced by dosing the bufadienolides to sheep or by injecting them into both guinea-pigs (subcutaneously) and sheep (intravenously). The specific paretic syndrome, krimpsiekte , on the other hand, was reproduced only by the repeated intravenous administration of smaller doses of the 2 unknown bufadienolides to sheep. Histopathological examination revealed a mild to severe multifocal cardiomyopathy in sheep receiving plant material or bufadienolides .

The experimental production of krimpsiekte in sheep with Tylecodon grandiflorus (Burm.f.) Toelken and some of its bufadienolides.

Six bufadienolides were isolated from Tylecodon grandiflorus ( Burm .f.) Toelken . The paretic syndrome, krimpsiekte , could be induced in sheep either by repeated oral administration of small quantities of plant material or the intravenous injection of small quantities of certain bufadienolides . A mild to moderate, acute to subacute, multifocal cardiomyopathy was evident in sheep poisoned by both the plant and the bufadienolides .

Attempted prevention and treatment of Geigeria filifolia Mattf. poisoning (vermeersiekte) in sheep.

A pilot trial with 2 sheep per group demonstrated that no protection is provided by cysteine, sulphur or sodium thiosulphate, when administered simultaneously with daily doses of Geigeria filifolia plant material. Treatment with piracetam of 4 sheep showing symptoms of vermeersiekte did not improve their recovery rate. Serum enzyme activity tests for creatine phosphokinase, glutamic oxaloacetic transaminase and gamma glutamyl transpeptidase were of no diagnostic use.

The effect of pre-dosing Homeria pallida Bak. to cattle to prevent tulp poisoning.

Newly weaned calves with no previous exposure to Homeria pallida were dosed with H. pallida material prepared as a broth, a suspension of charred leaves of leaves chopped into small shreds. Three hours later they were put into a camp where H. pallida constituted 50% of the grazing. Equal numbers of animals in each of the treated groups and in the untreated group subsequently developed H. pallida poisoning. By about the 4th day, both the treated and untreated animals appeared to have adapted to H. pallida and to avoid it while grazing.

The treatment of Moraea polystachya (Thunb) KER-GAWL (cardiac glycoside) poisoning in sheep and cattle with activated charcoal and potassium chloride.

Six out of 6 steers survived a lethal dose of Moraea polystachya (blue tulp) when treated with activated charcoal alone and 3 out of 4 wethers survived when treated with activated charcoal plus potassium chloride. Barbeque charcoal was not of therapeutic value. An increase in the level of serum potassium served as indicator of acute poisoning in only a third of the animals.

The minimal effective dose of activated charcoal in the treatment of sheep poisoned with the cardiac glycoside containing plant Moraea polystachya (Thunb) KER-GAWL.

The approximate minimal effective dose of activated charcoal, given to sheep 12 h after the administration of a lethal dose of Moreae polystachya, was found to be 2 g/kg. Serum cation levels remained within normal limits throughout the experiment.

The treatment of Urginea sanguinea Schinz poisoning in sheep with activated charcoal and potassium chloride.

An 80% survival rate was achieved when sheep which received lethal doses of Urginea sanguinea were treated with activated charcoal at 5 g/kg and potassium chloride at 1 g/kg body mass per os. A brief description of U. sanguinea poisoning and of the mechanism of cardiac glycoside action is given. Clinical examinations, ECG recordings and serum potassium levels were done to monitor developing signs of poisoning.