Copper poisoning in the Kruger National Park: field investigation in wild ruminants

Chronic copper poisoning was investigated in ruminants within the Phalaborwa area of the Kruger National Park (KNP). Exposure of ruminants to environmental copper pollution resulting from copper smelting operations of a mine in the area was examined by comparing impala faecal copper concentrations in dung heaps and tissue (liver, lung and kidney) copper concentrations of organs collected from impala and buffalo culled within three risk zones (high, moderate and low) of the study area in relation to the distance from the smelter over a period of 4 years. An additional area within the KNP not exposed to the environmental copper pollution from the mine served as control. Tissue copper accumulation was also determined in tracer impala placed in the highest risk zone. The results of this study confirmed the occurrence of chronic copper poisoning in impala and indicated an inverse relationship in extent of impala faecal copper elimination and in tissue copper accumulation in impala and buffalo with distance from the copper smelter. Impala liver copper concentrations were shown to be a reliable indicator of copper accumulation for these ruminants. The presence lung copper concentrations, indicating the exposure to airborne copper were the highest in impala culled in the zone closest to the smelter. Liver copper concentrations above the diagnostic limit of 150 ppm for chronic copper poisoning in domestic sheep were consistently found in impala within the highest risk zone. Clinical pathological measurements suggested that AST activity could possibly be used as an indicator for chronic copper poisoning in impala. It is concluded that, in addition to the environmental and geo-botanical evidence previously reported, the copper smelter of a nearby copper mine is the most likely source of copper pollution responsible for chronic copper poisoning in impala and the occurrence of high copper concentrations in buffalo in the Phalaborwa area of the KNP.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Palabora Mining Company. National Parks Board.mn201

Attempted induction of chronic copper poisoning in boma confined impala

Induction of chronic copper poisoning in ten boma-confined impala was attempted in a randomized, single dose, parallel designed, titration study using five increasing oral doses, ranging between 125 mg/kg to 1000 mg/kg, of copper oxide needles. Two untreated impala were kept as controls. Impala (n = 1) from each treatment group were culled 52 d and 105 d after treatment and examined for tissue copper accumulation and signs of chronic copper poisoning. Despite the high doses of copper administered to the impala and liver copper concentrations above 150 ppm WM achieved in two animals, no clinical signs related to chronic copper poisoning were observed. Faecal copper concentrations indicated that the major portion of copper oxide particles was excreted in the faeces.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Palabora Mining Company. National Parks Board.mn201

Paired-ion extraction and high-performance liquid chromatographic determination of diminazene in cattle plasma: a modified method

The high-performance liquid chromatographic method published by Aliu & Odegaard (1983) was found to give poor peak separation when used to determine plasma diminazene concentrations in cattle. Before bioequivalence studies could be carried out, the method had to be modified. Solid-phase extraction with acetonitrile/0,025 M Na-octane sulphonate and 2% acetic acid as eluent, followed by sample concentration, gave recoveries of > 90% for diminazene and the internal standard. A mobile phase of acetonitrile/0,005 M Na-octane sulphonate, 0,1% triethylamine, pH 3,2 with acetic acid on a Nova Pak C 18 column was used for the analysis. Wavelength switching was used to determine the internal standard (imidocarb) and diminazene at their respective wavelengths of maximum absorbance, resulting in a fivefold increase in the limit of detection for diminazene. The modified method attained a detection limit of 2 ng/ml (peak 4x baseline noise) , limit of quantitation of 10 ng/ml (coefficient of variation 96% over the range from 10-5000 ng/ml.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Milborrow Animal Health. University of Pretoria.mn201

Stability and partitioning of closantel and rafoxanide in ruminal fluid of sheep

The stability and the partitioning of closantel and rafoxanide in ruminal fluid (RF) was examined in vitro. Stability was evaluated in two studies in a ruminal fluid-artificial saliva (RF-AS) mixture containing either drug. Drug concentrations were measured in samples collected sequentially from four batches of RF-AS fortified with either closantel or rafoxanide in one study and in four separately incubated aliquots of a RF-AS mixture of each drug in the second study at the start and at various intervals during a 24 h incubation period. The viability of the in vitro RF-AS incubation model was validated by the presence of digoxin degradation (T1/2 of 39.1±13 h) and by the absence of significant time related differences (P>0.5) in volume of gas produced, pH and methylene blue reduction time of the RF-AS drug mixture. Partitioning of closantel and rafoxanide was determined by measuring the relative drug concentration of the fluid and particulate phases in RF fortified with either drug at different concentrations. Closantel and rafoxanide were shown to be stable in a RF-AS mixture and were not subjected to any significant biodegradation. An initial marked reduction in drug concentration measured in the RF-AS mixture during the first 2 h of incubation was attributed to the attachment of both drugs onto particulate matter. This was subsequently confirmed in the partitioning study. More than 80% of closantel and rafoxanide was shown to be associated with the particulate phase of RF.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Faculty of Veterinary Science, University of Pretoria.mn2012ab201

Evaluation of the efficacy of d-penicillamine and trientine as copper chelators using an in vitro technique involving ovine red blood cells

An in vitro technique for haemolysing ovine red blood cells with copper sulphate was standardized to induce c 50% haemolysis with 0,5 mM CuSO₄ after incubation for 14 h at 38°C. This technique was then applied to test the efficacy of trientine and d-penicillamine in preventing haemolysis. Trientine concentrations of 0,5; 1,0 and 1,5 mM were found to be the most effective (P<0,05) in reducing copper-induced haemolysis. One and 1,5 mM concentrations of d-penicillamine were also effective (P< 0,05), but in this experiment a 0,5 mM concentration failed to protect the erythrocytes.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Palabora Mining Company.mn201

Antimicrobial and anti-inflammatory activity of four known and one new triterpenoid from Combretum imberbe (Combretaceae)

Please open article to read abstractWe thank our colleagues at the HKI department of Biomolecular Chemistry for providing spectral data. Financial support by the German Academic Exchange Service (DAAD, to J.E.A.), the German Ministry for Education and Research (BMBF, CHN 02/322), National Research Foundation and University of Pretoria is gratefully acknowledged

Removing the Threat of Diclofenac to Critically Endangered Asian Vultures

Veterinary use of the nonsteroidal anti-inflammatory (NSAID) drug diclofenac in South Asia has resulted in the collapse of populations of three vulture species of the genusGyps to the most severe category of global extinction risk. Vultures are exposed to diclofenac when scavenging on livestock treated with the drug shortly before death. Diclofenac causes kidney damage, increased serum uric acid concentrations, visceral gout, and death. Concern about this issue led the Indian Government to announce its intention to ban the veterinary use of diclofenac by September 2005. Implementation of a ban is still in progress late in 2005, and to facilitate this we sought potential alternative NSAIDs by obtaining information from captive bird collections worldwide. We found that the NSAID meloxicam had been administered to 35 captiveGyps vultures with no apparent ill effects. We then undertook a phased programme of safety testing of meloxicam on the African white-backed vultureGyps africanus, which we had previously established to be as susceptible to diclofenac poisoning as the endangered AsianGyps vultures. We estimated the likely maximum level of exposure (MLE) of wild vultures and dosed birds by gavage (oral administration) with increasing quantities of the drug until the likely MLE was exceeded in a sample of 40G. africanus. Subsequently, sixG. africanus were fed tissues from cattle which had been treated with a higher than standard veterinary course of meloxicam prior to death. In the final phase, ten Asian vultures of two of the endangered species(Gyps bengalensis,Gyps indicus) were dosed with meloxicam by gavage; five of them at more than the likely MLE dosage. All meloxicam-treated birds survived all treatments, and none suffered any obvious clinical effects. Serum uric acid concentrations remained within the normal limits throughout, and were significantly lower than those from birds treated with diclofenac in other studies. We conclude that meloxicam is of low toxicity toGyps vultures and that its use in place of diclofenac would reduce vulture mortality substantially in the Indian subcontinent. Meloxicam is already available for veterinary use in India

Diclofenac toxicity in Gyps vulture is associated with decreased uric acid excretion and not renal portal vasoconstriction

Diclofenac (DF), a non-steroidal anti-inflammatory drug (NSAID), is largely regarded as one of the most devastating environmental toxicant in recent times, after accidental exposure via their food-chain lead to massive mortalities in three vulture species on the Asian subcontinent. Although the use of diclofenac was recently banned on the Indian subcontinent, following the favourable safety profile of meloxicam, its mechanism of toxicity remains unknown. In an attempt to establish this mechanism, we test three hypotheses using models established from either the domestic chicken (Gallus domesticus) or the African White-backed vulture (Gyps africanus). We demonstrate that both DF and meloxicam are toxic to renal tubular epithelial (RTE) cells following 12 h of exposure, due to an increase in production of reactive oxygen species (ROS), which could be temporarily ameliorated by pre-incubation with uric acid (UA). When cultures were incubated with either drug for only 2 h, meloxicam showed no toxicity in contrast to diclofenac. In both cases no increase in ROS production was evident. In addition, diclofenac decreased the transport of uric acid, by interfering with the p-amino-hippuric acid (PAH) channel. We conclude that vulture susceptibility to diclofenac results from a combination of an increased ROS, interference with UA transport and the duration of exposure.Royal Society for the Protection of Birds (RSPB). National Research Foundation of South Africa (NRF). Bayer Animal Health South Africa

Veterinary education in Africa : current and future perspectives

Veterinary education commenced in South Africa in 1920 at the Onderstepoort Veterinary Institute in South Africa in association with the Transvaal University College, now the University of Pretoria. Sir Arnold Theiler, Director of Veterinary Research and Education, was the first Dean. Today there are 46 veterinary training institutions in Africa of which 21 are in sub-Saharan Africa.Veterinary services are indispensable to the sustained health and wellbeing of animals and humans, and agricultural economies of countries worldwide. Veterinary education, postgraduate training, and research, and adequate numbers of veterinarians, are essential to satisfy the millennium development goals, the objectives of NEPAD and the African Union, and the agreements regulating international trade. The relevance of the veterinary profession internationally is currently subject to profound scrutiny. Its contributions are assessed against major environmental, demographic, political, disease, technological and economic needs. The scope of veterinary training in future will have to emphasise veterinary public health, food safety, emerging diseases, international trade, bioterrorism, and biomedical research, within the context of a one-health system focusing on the interface between wildlife, domesticated animals, humans, and their environment. Within the context of time available, it would mean reducing the time allocated to training in the field of companion animals. A brief history and scope of veterinary education; current international trends in veterinary education and provisioning; and some perspectives on future veterinary training and initiatives applicable to Africa are provided