A premature stop codon in the CYP2C19 gene may explain the unexpected sensitivity of vultures to diclofenac toxicity.

The unintended environmental exposure of vultures to diclofenac has resulted in the deaths of millions of old-world vultures on the Asian subcontinent. While toxicity has been since associated with a long half-life of elimination and zero order metabolism, the actual constraint in biotransformation is yet to be clarified. For this study we evaluated if the evident zero order metabolism could be due to defects in the CYP2C9/2C19 enzyme system. For this, using whole genome sequencing and de-novo transcriptome alignment, the vulture CYP2C19 open reading frame was identified through Splign analysis. The result sequence analysis revealed the presence of a premature stop codon on intron 7 of the identified open reading frame. Even if the stop codon was not present, amino acid residue analysis tended to suggest that the enzyme would be lower in activity than the equivalent human enzyme, with differences present at sites 105, 286 and 289. The defect was also conserved across the eight non-related vultures tested. From these results, we conclude that the sensitivity of the old-world vultures to diclofenac is due to the non-expression of a viable CYP2C19 enzyme system. This is not too dissimilar to the effects seen in certain people with a similar defective enzyme.

Sub-lethal impacts of lead poisoning on blood biochemistry, immune function and delta-aminolevulinic acid dehydratase (δ-ALAD) activity in Cape (Gyps coprotheres) and white-backed (G. africanus) Vulture chicks.

Although the prevalence of lead poisoning in southern Africa's Gyps vultures is now well-established, its finer physiological effects on these endangered species remain poorly characterised. We evaluated the sub-lethal impact of acute lead exposure on Cape and White-backed Vulture chicks from two breeding colonies in South Africa, by analysing its possible effects on key blood biochemistry parameters, immune function, packed cell volume and δ-aminolevulinic acid dehydratase (δ-ALAD) activity. All 37 White-backed Vulture nestlings sampled displayed elevated lead levels (>10 µg/dL), and seven had blood [Pb] >100 µg/dL. Eight of 28 Cape Vulture nestlings sampled had blood [Pb] exceeding background exposure, with one showing blood [Pb] >100 µg/dL. Delta-aminolevulinic acid dehydratase (δ-ALAD) activity was significantly and negatively related to blood [Pb] in nestlings from both species, with 50% inhibition of the enzyme predicted to occur at blood [Pb] = 52.8 µg/dL (White-backed Vulture) and 18.8 µg/dL (Cape Vulture). Although no significant relationship was found between % packed cell volume (PCV) and blood [Pb], the relatively lower mean PCV of 32.9% in White-backed Vulture chicks, combined with normal serum protein values, is likely indicative of depression or haemolytic anaemia. The leukogram was consistent in both species, although the presence of immature heterophils suggested an inflammatory response in White-backed Vulture chicks with blood [Pb] >100 µg/dL. Values for cholesterol, triglycerides, total serum protein, albumin, globulin, albumin/globulin ratio, alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) were consistent with values previously reported. Calcium and phosphorus concentrations suggested no adverse effects on bone metabolism. A significant decrease in urea: uric acid (U:UA) ratio at blood [Pb] >100 µg/dL in White-backed Vulture chicks, brought about by a decrease in urea production, raises the possibility of hepatic abnormality. These results suggest that δ-ALAD activity may serve as a sensitive biomarker of lead toxicity in both species, while highlighting the need to better understand the significant variability in sensitivity that is observed, even between closely related members of the same genus.

THE IMPACT OF SUPPLEMENTARY FEEDING OF PIG CARCASSES ON PLASMA VITAMIN E CONCENTRATIONS IN CAPTIVE CAPE VULTURES (GYPS COPROTHERES).

With vulture population numbers on the decline globally, many countries resort to supplementary feeding to maintain colony health. Despite what is perceived as adequate feeding in South Africa, colonies are still characterized by poor breeding success. One reason could be that supplementary sites fail to meet micronutrient needs of birds. With results from zoological gardens indicating that some carcasses are low in their vitamin E concentrations, vitamin deficiencies may be an underlying problem. For this study it was determined if the feeding of whole pig carcasses, a common food item, could have a negative effect on plasma vitamin E concentrations in a captive colony. Plasma vitamin E concentrations were 7.38 ± 2.92 and 4.51 ± 1.24 after feeding whole pig carcasses (n = 14). Behaviorally, the birds also avoided the viscera and fat when feeding. Reasons for their low vitamin E concentrations could have resulted from the birds consuming only the pork meat, which is known to be low in vitamin E, or from natural peroxidation because of the high fat content of the carcasses. The study thus highlights the need for further research to ascertain the impact of feeding pig carcasses on wild vultures feeding routinely at supplementary feeding sites and also for considerations towards vitamin E supplementation.

Do Pathogenic Escherichia coli Isolated from Gallus gallus in South Africa Carry Co-Resistance Toward Colistin and Carbapenem Antimicrobials?

Colistin and carbapenems are critically important antimicrobials often used as a last resort to manage multidrug-resistant bacterial infections in humans. With limited alternatives, resistance to these antimicrobials is of concern as organisms could potentially spread horizontally rendering treatments ineffective. The aim of this study was to investigate co-resistance to colistin and carbapenems among Escherichia coli isolated from poultry in South Africa. Forty-six E. coli strains obtained from clinical cases of breeder and broiler chickens were used. In addition to other antibiotics, all the isolates were tested against colistin and carbapenems using broth microdilution. Multiplex polymerase chain reactions were used to investigate the presence of colistin (mcr-1 to 5) and carbapenem (blaOXA-48, blaNDM-1, and blaVIM) resistance genes. Isolates exhibiting colistin resistance (>2 µg/mL) underwent a whole-genome sequencing analysis. Resistance to colistin (10.9%) and cefepime (6.5%) was noted with all colistin-resistant strains harboring the mcr-1 gene. None of the E. coli isolates were resistant to carbapenems nor carried the other resistant genes (mcr-2 to 5, blaOXA-48, blaNDM-1, and blaVIM). The mcr-1-positive strains belonged to sequence types ST117 and ST156 and carried virulence genes ompA, aslA, fdeC, fimH, iroN, iutA, tsh, pic, ast A and set 1A/1B. In conclusion, clinical E. coli strains from chickens in this study possessed mobile resistance genes for colistin and several other clinically relevant antimicrobials but not carbapenems. Additionally, they belonged to sequence types in addition to carrying virulence factors often associated with human extraintestinal pathogenic E. coli infections. Thus, the potential risk of transmitting these strains to humans cannot be underestimated especially if sick birds are dispatched into the thriving poorly regulated Cornish hen industry. The need for routine veterinary surveillance and monitoring of antimicrobial resistance, antimicrobial use and the importance of strengthening regulations guiding the informal poultry sector remains important.

Disposition of posaconazole after single oral administration in large falcons (Falco spp): Effect of meal and dosage and a non-compartmental model to predict effective dosage.

Posaconazole has been used anecdotally to treat aspergillosis in falcons resistant to voriconazole. In human medicine, it is used prophylactically in immunosuppressed human subjects with invasive pulmonary aspergillosis. So far, no studies have been performed in birds. The aim of this study was to evaluate the in-vivo pharmacokinetic behavior of oral posaconazole after a single administration in six large falcons (i.e gyrfalcons, saker falcons). Posaconazole oral suspension (Noxafil, 40 mg/ml, Schering-Plough) was administered per os without meal in a single dosage of 12.5 mg/kg in 3 falcons. A comparison was done in two more falcons, one with a natural fatty meal at the same single dose, and one with a natural fatty meal and a higher dosage (20 mg/kg). Finally, six falcons received posaconazole pre-dissolved in corn oil with a natural low-fat meal in the higher single dose (20 mg/kg). No side effects were observed in the falcons in any of the experiments. In starved state posaconazole was poorly absorbed, more so than in other species. As expected, absorption of posaconazole was higher with the administration of meal or in the presence of plant (corn) oil, with a fourfold increase in apparent bioavailability. Despite the preferential absorption in the presence of fat, for both dosing schemes the AUC24 : MIC ratio was lower than described in human medicine to achieve a therapeutic effect. The AUCinf : MIC which is an indicator of efficacy after steady-state, while variable, did indicate that the drug is worth trying when susceptibility testing shows to be the only effective drug. LAY ABSTRACT: The focus of this work is to determine the pharmacokinetic parameters of oral posaconazole in large falcons for the first time after a single dose. Posaconazole has higher bioavailability when administered with meal and fatty components. No adverse reactions have been observed. The ratio of the area under the curve (AUC24) to minimum inhibitory concentration was lower compared to the therapeutic level in human.

Pharmacokinetics of an intravenous and oral dose of enrofloxacin in white rhinoceros (Ceratotherium simum).

South Africa currently loses over 1000 white rhinoceros (Ceratotherium simum) each year to poaching incidents, and numbers of severely injured victims found alive have increased dramatically. However, little is known about the antimicrobial treatment of wounds in rhinoceros. This study explores the applicability of enrofloxacin for rhinoceros through the use of pharmacokinetic-pharmacodynamic modelling. The pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin were evaluated in five white rhinoceros after intravenous (i.v.) and after successive i.v. and oral administration of 12.5 mg/kg enrofloxacin. After i.v. administration, the half-life, area under the curve (AUCtot ), clearance and the volume of distribution were 12.41 ± 2.62 hr, 64.5 ± 14.44 µg ml-1  hr-1 , 0.19 ± 0.04 L h-1  kg-1 , and 2.09 ± 0.48 L/kg, respectively. Ciprofloxacin reached 26.42 ± 0.05% of the enrofloxacin plasma concentration. After combined i.v. and oral enrofloxacin administration oral bioavailability was 33.30 ± 38.33%. After i.v. enrofloxacin administration, the efficacy marker AUC24 : MIC exceeded the recommended ratio of 125 against bacteria with an MIC of 0.5 µg/mL. Subsequent intravenous and oral enrofloxacin administration resulted in a low Cmax: MIC ratio of 3.1. The results suggest that intravenous administration of injectable enrofloxacin could be a useful drug with bactericidal properties in rhinoceros. However, the maintenance of the drug plasma concentration at a bactericidal level through additional per os administration of 10% oral solution of enrofloxacin indicated for the use in chickens, turkeys and rabbits does not seem feasible.

Antimicrobial resistance among Escherichia coli isolates from dogs presented with urinary tract infections at a veterinary teaching hospital in South Africa.

BACKGROUND: This study investigated the burden and predictors of canine E. coli urinary tract infections (UTI) and antimicrobial resistance among dogs presented at a veterinary teaching hospital in South Africa, 2007-2012. METHODS: The Cochran-Armitage trend test was used to investigate temporal trends while logistic regression models were used to investigate predictors (age, sex, breed, year) of E. coli infections and antimicrobial resistance (AMR). RESULTS: A total of 22.3% (168/755) of the urinary specimens tested positive for E. coli. A significant (p = 0.0004) decreasing temporal trend in the percentage of E. coli positive isolates was observed over the study period. There were high levels of AMR to penicillin-G (99%), clindamycin (100%), tylosine (95%), cephalothin (84%) but relatively low levels of resistance to enrofloxacin (16%), orbifloxacin (21%). Almost all (98%, 164/167) the isolates exhibited multidrug resistance (MDR), while only 11% (19/167) and 2% (4/167) exhibited extensive drug resistance (XDR) and pan-drug resistance (PDR), respectively. CONCLUSIONS: Although, the risk of E. coli UTI declined during the study period, the risk of AMR increased. The high levels of AMR and MDR as well as the presence of XDR and PDR is concerning as these have the potential of affecting prognosis of UTI treatments.

Isolation and characterization of two acaricidal compounds from Calpurnia aurea subsp. aurea (Fabaceae) leaf extract.

The menace caused by ticks and tick-borne diseases is a major limitation to the livestock industry in Africa. The high costs and non-availability of synthetic, chemical acaricides to resource-limited farmers, resistance of ticks to available acaricides and residue problems in meat and milk consumed by humans further complicate matters. The use of plant extracts as a possible source of new acaricides has received much interest in the last decade. In our endeavour to discover natural acaricidal compounds, tick toxicant bioassays were conducted and the chloroform fraction of Calpurnia aurea ethanol leaf extract had good acaricidal activity. Further purification of the fraction revealed two flavonoids, isolated from C. aurea for the first time. These flavonoids were characterized as apigenin-7-O-ß-D-glycoside and isorhoifolin by means of NMR spectroscopic and mass spectrometry analysis. Isorhoifolin was the most potent compound (LC50 = 0.65 mg/ml), was not cytotoxic and should be further investigated for its potential as an acaricidal agent.

The use of primary murine fibroblasts to ascertain if Spirocerca lupi secretory/excretory protein products are mitogenic ex vivo.

BACKGROUND: Spirocerca lupi is a nematode that parasitizes vertebrates in particular canids, by forming nodules in the thoracic cavity specifically in the oesophagus. In 25% of Spirocerca infections of the domestic dog, nodules progress from inflammatory to pre-neoplastic to sarcomatous neoplasia. With the mechanism of neoplastic transformation being incompletely understood, this study investigates if S. lupi parasite proteinaceous secretory/excretory products (ESPs) play a role in the neoplastic transformation. METHODS: To facilitate collection of ESPs, we maintained naturally harvested adult parasites in the laboratory under artificial conditions. Media in which the parasites were grown was subsequently evaluated for the presence of proteinaceous compounds using a mass spectroscopy library as well as for their ability to be mitogenic in primary murine fibroblastic cells. RESULTS: Chromatrography of the ethyl acetate extracted incubation media showed the presence of 9 protein compounds, of which three were identified as non-specific proteins isolated from Nematostella vectensis, Caenorhabditis brenneri and Sus scrofa, with the rest being unknown. Acetone, methanol, hexane and ethylacetate extracted culture media were unable to induce a mitogenic change in primary murine fibroblasts in comparison to the controls. CONCLUSION: While no mitogenic effect was evident, further studies are required to understand the role of worm excretory/secretory products on clastogenesis under chronic exposure. In addition, while not of primary importance for this study, the observed duration of parasite survival indicates that ex vivo studies on S. lupi are possible. For the latter we believe that the worm culture method can be further optimized if longer survival times are required.

Antidiabetic activity of the ethyl acetate fraction of Ficus lutea (Moraceae) leaf extract: comparison of an in vitro assay with an in vivo obese mouse model.

BACKGROUND: Ficus lutea crude acetone leaf extracts were previously shown to stimulate glucose uptake and insulin secretion of established cells and, inhibit α-amylase and α-glucosidase activities. METHODS: For this study, F. lutea acetone extracts were subjected to solvent-solvent fractionation to yield fractions with differing polarities (hexane, chloroform, dichloromethane, ethyl acetate, n-butanol and water) in an attempt to obtain a more potent fraction with in vitro and probably in vivo activity. RESULTS: Among these fractions, the ethyl acetate fraction had the highest total polyphenol content (100.5 ± 1.6 mg GAE/g dried extract) and α-glucosidase inhibitory activity (126.8 ± 30.6 µg/ml). It also stimulated the highest glucose uptake of C2C12 muscle cells and decreased extracellular glucose concentration of H-4-II-E liver cells with low cytotoxic activity. The ethyl acetate fraction (10.88 ± 0.55 µg/L at 250 µg/ml) enhanced insulin secretion in RIN-m5F pancreatic ß-cells to the same degree as the positive control glibenclamide (11.09 ± 0.07 µg/L at 1µM). While fractionation increased α-glucosidase inhibition and glucose uptake of cells, in the ethyl acetate fraction, the α-amylase inhibition and insulin secretion decreased. The weight reducing and glucose control potential of the ethyl acetate fraction in an obese mouse model, important factors in the amelioration of type II diabetes was determined. The extract had no statistical significant weight reducing activity. CONCLUSION: A major finding was the decrease in the area under the curve of the glucose concentration over time in animals that were treated with both a change in diet and with the plant extract. This is linked to increased glucose uptake within the cells, the most likely mechanism is either an increased insulin response or increased insulin secretion.

Accelerated induction of etorphine immobilization in blue wildebeest (Connochaetes taurinus) through the addition of hyaluronidase.

OBJECTIVE: To study the effects of the addition of hyaluronidase (HA) to an etorphine/azaperone drug combination on induction times of immobilization. STUDY DESIGN: Experimental part-randomized 'blinded' cross-over study. ANIMALS: Eight wild managed blue wildebeest (Connochaetes taurinus). METHODS: Animals were immobilized, on separate occasions separated by two weeks, with one of four treatments. Treatments were; 'Control drugs (CD), etorphine 0.01 mg kg(-1)  + azaperone at 0.1 mg kg(-1) ; treatment 1 CD + 5000IU HA; treatment 2 CD + 7500 IU HA; and treatment 3 etorphine 0.007 mg kg(-1)  + azaperone at 0.07 mg kg(-1)  + 7500 IU HA. Times to first effect and to immobilization (from darting to possible to approach and blindfold) were measured. anova was used to compare treatments. Results are given in means ± SD (range). RESULTS: For control, and treatments 1-3 respectively, times (in minutes) to first effect were 1.58 ± 0.42 (1.02-2.10), 1.64 ± 0.42 (0.95-2.17), 1.12 ± 0.24 (0.80-1.48) and 1.60 ± 0.21 (1.13-1.88) and to immobilization were 5.38 ± 1.53 (3.82-8.07), 3.80 ± 1.14 (2.02-5.50), 3.51 ± 1.08 (2.28-5.52) and 4.46 ± 0.67 (3.30-5.40). Compared to control, time to first effect for treatment 2 was significantly shorter. Time to immobilization was significantly quicker in all three treatments containing HA than that for control. CONCLUSION AND CLINICAL RELEVANCE: Hyaluronidase can reduce the time to immobilization when used in the immobilizing dart, and might be usefully incorporated into etorphine combinations for darting wildlife.

The antibacterial activity, antioxidant activity and selectivity index of leaf extracts of thirteen South African tree species used in ethnoveterinary medicine to treat helminth infections.

BACKGROUND: Diseases caused by bacteria remain a major challenge globally and particularly in sub-Saharan Africa. The plants used in this study have been used in South Africa to treat helminth infections in livestock and humans. In a previous study we found a correlation between antifungal and anthelmintic activity in some cases. In this study we examined other potential uses of these thirteen plant species by determining the antibacterial and antioxidant activity of the leaf acetone extracts.The antibacterial activity was determined by using a serial microdilution method against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis. Bioautography was used to determine the number of antibacterial compounds. The antioxidant activity was determined using the ABTS and DPPH methods. RESULTS: Maesa lanceolata and Leucosidea sericea with an MIC of 0.02 mg/ml had excellent antibacterial activity against Enterococcus faecalis and Pseudomonas aeruginosa. There was a poor correlation between antioxidant activity and antibacterial activity with R2 = 0.143. This is because antibacterial activity is mainly related to non-polar compounds and antioxidant activity to polar compounds. Maesa lanceolata extracts had a low cytotoxicity with a selectivity index of 5.2, 2.6, 2.6 and 1.3 for P. aeruginosa, E. faecalis, E. coli and S. aureus respectively. Strychnos mitis extracts had a therapeutic index of 1.1 for E. coli. CONCLUSIONS: This study shows that plant extracts of some species used in ethnoveterinary medicine as anthelmintic may also have excellent antibacterial activity.

The potential role of GLUT4 transporters and insulin receptors in the hypoglycaemic activity of Ficus lutea acetone leaf extract.

BACKGROUND: Some Ficus species have been used in traditional African medicine in the treatment of diabetes. The antidiabetic potential of certain species has been confirmed in vivo but the mechanism of activity remains uncertain. The aim was to investigate the hypoglycaemic potential of ten Ficus species focussing on glucose uptake, insulin secretion and the possible mechanism of hypoglycaemic activity. METHODS: The dried and ground leaves of ten Ficus species were extracted with acetone. The dried acetone extract was reconstituted with DMSO to a concentration of 100 mg/ml which was then serially diluted and used to assay for glucose uptake in muscle, fat and liver cells, and insulin secretion in pancreatic cells. RESULTS: Only the F. lutea extract was able to modulate glucose metabolism. In comparison to insulin in the primary muscle cells, the glucose uptake ability of the extract was 33% as effective. In the hepatoma cell line, the extract was as effective as metformin in decreasing extracellular glucose concentration by approximately 20%. In the pancreatic insulin secretory assay, the extract was 4 times greater in its secretory activity than commercial glibenclamide. With F. lutea extract significantly increasing glucose uptake in the primary muscle cells, primary fat cells, C2C12 muscle and H-4-II-E liver cells, the extract may act by increasing the activity of cell surface glucose transporters. When the 3T3-L1 pre-adipocytes were compared to the primary muscle, primary fat and C2C12 cells, the differences in the former's ability to transport glucose into the cell may be due to the absence of the GLUT4 transporter, which on activation via the insulin receptor decreases extracellular glucose concentrations. Because the pre-adipocytes failed to show any active increase in glucose uptake, the present effect has to be linked to the absence of the GLUT4 transporter. CONCLUSION: Only F. lutea possessed substantial in vitro activity related to glucose metabolism. Based on the effect produced in the various cell types, F. lutea also appears to be a partial agonist/antagonist of the insulin cell membrane receptor. While the clinical effectiveness of F. lutea is not known, this plant species does possess the ability to modify glucose metabolism.

Prevalence of colistin resistance and antibacterial resistance in commensal Escherichia coli from chickens: An assessment of the impact of regulatory intervention in South Africa.

BACKGROUND: Antimicrobial resistance (AMR) is a global health problem largely due to the overuse of antimicrobials. In recognition of this, the World Health Assembly in 2015 agreed on a global action plan to tackle AMR. Following the global emergence of the mcr-1-associated colistin resistance gene in the livestock industry in 2016, several countries including South Africa restricted the veterinary use of colistin as the gene threatens the clinical utility of the drug. This study is a follow-up to the restriction in place in order to evaluate the impact of such policy adoption. OBJECTIVE: To assess the prevalence of antibacterial resistance (ABR), and the mcr-1 colistin resistance gene in broiler chicken over a 2-year period, as a follow-up to the veterinary ban on colistin use in South Africa. METHODS: A total of 520 swab samples were obtained during 2019 (March-April) and 2020 (February-March), from healthy broiler chicken carcasses (n = 20) and chicken droppings in transport crates (n = 20) at various poultry abattoirs (N = 7) in the Gauteng province of South Africa. Escherichia coli organisms were isolated and subjected to a panel of 24 antibacterials using the MicroScan machine. Screening for mcr-1 colistin resistance gene was undertaken using PCR. RESULT: Four hundred and thirty-eight (438) E. coli strains were recovered and none demonstrated phenotypic resistance towards colistin, amikacin, carbapenems, tigecycline and piperacillin/tazobactam. The mcr-1 gene was not detected in any of the isolates tested. Resistances to the aminoglycosides (0%-9.8%) and fluoroquinolones (0%-18.9%) were generally low. Resistances to ampicillin (32%-39.3%) and trimethoprim/sulphamethoxazole (30.6%-3.6%) were fairly high. A significant (p < 0.05) increase in cephalosporins and cephamycin resistance was noted in the year 2020 (February-March) when compared with the year 2019 (March-April). CONCLUSION: The absence of mcr-1 gene and colistin resistance suggests that mitigation strategies adopted were effective and clearly demonstrated the significance of regulatory interventions in reducing resistance to critical drugs. Despite the drawback in regulatory framework such as free farmers access to antimicrobials OTC and a dual registration system in place, there is a general decline in the prevalence of ABR when the present data are compared with the last national veterinary surveillance on AMR (SANVAD 2007). To further drive resistance down, mitigation strategies should focus on strengthening regulatory framework, the withdrawal of OTC dispensing of antimicrobials, capping volumes of antimicrobials, banning growth promoters and investing on routine surveillance/monitoring of AMR and antimicrobial consumption.

Naja nigricincta nigricincta venom, a murine model. Evaluation of skeletal and cardio-myonecrosis, kidney injury and inflammatory response along with neutralisation efficacy by the SAIMR/SAVP - And EchiTAb-Plus-ICP polyvalent antivenoms.

African spitting cobra, Naja nigricincta nigricincta (Zebra snake), envenomation is an important cause of snakebite morbidity and mortality in Namibia. The snake is endemic to central and northern Namibia as well as southern Angola. The venom is mainly cytotoxic, resulting in aggressive dermo-necrosis and often accompanied by severe systemic complications. No specific antivenom exists. Rhabdomyolysis, systemic inflammatory response, haemostatic abnormalities, infective necrotising fasciitis as well as acute kidney failure have been documented. Based on murine models, this study assessed SAVP/SAIMR - and EchiTAb-Plus-ICP polyvalent antivenom neutralisation as well as subdermal necrosis. Additional muscle, cardiac, kidney and lung histology, creatine kinase measurements and post-mortems were performed. An intravenous median lethal dose (LD50) of Naja nigricincta nigricincta venom was determined at 18.4 (CI: 16.3; 20.52) µg and a subdermal lethal dose at 15.3(CI: 12.96; 17.74)µg. The SAIMR/SAVP polyvalent antivenom median effective dose (ED50) was 1.2 ml antivenom/1 mg venom equating to a potency (WHO) of 1 ml antivenom neutralising 0.63 mg venom and approximately 240 ml (24 vials) needed for initial treatment. The ED50 of the EchiTAb-Plus-ICP was 1 ml antivenom/1 mg venom and a potency of 65 mg venom/ml antivenom (3.3 x LD50), estimating 230 ml (23 vials) for treatment. Histology and serology (creatine kinase) evidenced venom induced skeletal myotoxicity, which was not prevented by the antivenoms tested. Cardiac myonecrosis, an inflammatory response, direct venom kidney tubular necrosis and cardio-pulmonary failure were documented.

Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems.

The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict 'unexpected' risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems.

Evaluation of the inhibition of carbohydrate hydrolysing enzymes, antioxidant activity and polyphenolic content of extracts of ten African Ficus species (Moraceae) used traditionally to treat diabetes.

BACKGROUND: Some Ficus species have been used in traditional African medicine in the treatment of diabetes. The antidiabetic potential of certain species has been confirmed in vivo but the mechanism of activity remains uncertain. The aim of this study was to determine the activity and to investigate the mechanism of antidiabetic activity of ten selected Ficus species through inhibition of α-amylase and α-glucosidase activity, and the possible relationship between these activities, the total polyphenolic content and the antioxidant activity. METHODS: Dried acetone leaf extracts were reconstituted with appropriate solvents and used to determine total polyphenolic content antioxidant activity, α-amylase and α-glucosidase inhibitory activity. RESULTS: The crude acetone extract of F. lutea had the highest polyphenolic content (56.85 ± 1.82 mg GAE/g of dry material) and the strongest antioxidant activity with a TEAC value of 4.80 ± 0.90. The antioxidant activity of the acetone extracts of the Ficus species may not be ascribed to total polyphenolic content alone. The crude extract at a concentration of 0.5 mg/ml of F. lutea (64.3 ± 3.6%) had the best α-glucosidase (sucrase) inhibitory activity. The EC50 of F. lutea (290 ± 111 µg/ml) was not significantly different from that of F. sycomorus (217 ± 69 µg/ml). The α-amylase inhibitory activity of F. lutea (95.4 ± 1.2%) at a concentration of 1 mg/ml was the highest among the Ficus species screened. The EC50 for F. lutea (9.42 ± 2.01 µ g/ml), though the highest, was not significantly different (p < 0.05) from that of F. craterostoma and F. natalensis. It was apparent that the crude acetone extract of F. lutea is a partially non-competitive inhibitor of α-amylase and α-glucosidase. Based on correlation coefficients polyphenolics may be responsible for α-glucosidase activity but probably not for α-amylase activity. CONCLUSION: Antidiabetic activity potential via inhibition of α-amylase and α-glucosidase was discovered in Ficus lutea which has not been previously reported. The acetone extract of the leaves was high in total polyphenolic content and antioxidant activity, and was a potent inhibitor of α-amylase activity. Research is underway to isolate the active compound(s) responsible for the antidiabetic activity and to confirm the in vitro antidiabetic activity and to investigate in vitro toxicity.

Veterinary pharmaceuticals and declining Cape Griffon Vulture (Gyps coprotheres) numbers: A potential threat to developing embryos.

Cape Vultures (Gyps coprotheres) are a vulnerable Old-World Vulture species in southern Africa. Of the numerous threats to their survival, malicious and accidental poisonings remain a major concern. Despite the dangers of poisonings little is however known about the more insidious effects of toxins on egg survival, despite the species known to have a long generational length. For this study, an extensive literature review focusing on veterinary pharmaceuticals was undertaken. Literature for vultures was scarce, with most studies focusing on the domestic chicken. Using information for domestic chickens, the risk was characterised from likely vulture exposure to production animal carcasses with residues of said drugs. From this various antibiotics, medetomidine and albendazole were identified with embryotoxic or teratogenic effects. We suggest that these drugs be tested to elucidate their dose-response relationship and/or mitigation measures to minimise vulture exposure.

A Technical Report on the Potential Effects of Heat Stress on Antioxidant Enzymes Activities, Performance and Small Intestinal Morphology in Broiler Chickens Administered Probiotic and Ascorbic Acid during the Hot Summer Season.

Oxidative stress negatively affects the welfare of broiler chickens leading to poor productivity and even death. This study examined the negative effect of heat stress on antioxidant enzyme activities, small intestinal morphology and performance in broiler chickens administered probiotic and ascorbic acid during the hot summer season, under otherwise controlled conditions. The study made use of 56 broiler chickens; which were divided into control; probiotic (1 g/kg); ascorbic acid (200 mg/kg) and probiotic + ascorbic acid (1 g/kg and 200 mg/kg, respectively). All administrations were given via feed from D1 to D35 of this study. Superoxide dismutase, glutathione peroxidase and catalase activities were highly significant (p < 0.0001) in the treatment groups compared to the control. Performance indicators (water intake and body weight gain) were significantly higher (p < 0.05) in the probiotic and probiotic + ascorbic acid group. The height of duodenal, jejunal and ileal villi, and goblet cell counts of broiler chickens were significantly different in the treatment groups. In conclusion, the study showed that heat stress negatively affects the levels of endogenous antioxidant enzymes, performance and the morphology of small intestinal epithelium, while the antioxidants were efficacious in ameliorating these adverse effects.

Identifying the origin of lead poisoning in white-backed vulture (Gyps africanus) chicks at an important South African breeding colony: a stable lead isotope approach.

Elevated lead levels in scavenging raptors can originate from a variety of environmental and anthropogenic sources, including soil, water, mining activities and legacy lead from leaded fuel, but has mostly been attributed to fragments of lead-based ammunition embedded in the tissues of carcasses. To identify the origins of lead in the tissues of white-backed vulture (Gyps africanus) chicks at Dronfield Nature Reserve, South Africa, we used MC-ICP-MS to compare the isotopic composition of lead in blood samples to those of soil in the chicks' immediate environment, different mining activities in South Africa and lead ammunition commonly used in hunting and game management practices. The isotopic ratios in vulture blood samples ranged widely (207Pb/206Pb: 0.827-0.911), but fell within those measured for ammunition (0.761-0.938). Dronfield water can be excluded as a significant source, as the lead concentration for water was below detection limits. Uranium, coal, atmospheric Pb, legacy Pb from fuel and Pb mining can also be excluded as significant sources, based on the limited overlap with Pb isotopic ratios measured in vulture blood. Whereas 55% of chicks we sampled displayed isotopic ratios consistent with Dronfield soil, the low local Pb concentration and the low extractable Pb levels in South African soil in general, imply that soil Pb is unlikely the major source of Pb in WBV chicks, especially in birds with elevated blood Pb levels, i.e. > 20 µg/dL. Our results, when considered in the context of vulture feeding ecology and low Pb levels in non-scavenging birds in South Africa, imply the major source of elevated Pb levels in WBV chicks to be fragments of lead-based ammunition embedded in the carrion fed to them by their parents.