Chemical composition and acaricidal activity of Eucalyptus globulus essential oil against the vector of tropical bovine piroplasmosis, Rhipicephalus (Boophilus) annulatus.

Ticks are of great economic importance to humans and animals due to their role in disease transmission. The application of synthetic, chemical acaricides on the animal and/or the environment (the most used tick control method globally) has led to the selection of tick populations that are resistant. Their adverse effects on ecology and human and animal health cannot be overemphasised. As a result, the search for alternatives that are natural and can overcome these adverse effects are strongly indicated. Using gas chromatography-mass spectrometry (GC-MS) and adult immersion test (AIT), this study evaluated the chemical composition and acaricidal activity, respectively, of Eucalyptus globulus essential oil (EO) on Rhipicephalus (Boophilus) annulatus ticks. This is a major tick species implicated for the transmission of bovine piroplasmosis in Nigeria. The acaricidal activity was evaluated using different concentrations (0.625, 1.25, 2.5, 5 and 10%) of E. globulus EO. Amitraz (1 and 2%) and cypermethrin (2%) served as the positive control and 2% dimethylsulfoxide in distilled water was the negative control. Three replicates of 10 engorged female ticks each were immersed in the test samples for 2 min and the experiment was done twice. The GC-MS analysis identified the major constituents of E. globulus EO as eucalyptol (1,8-cineole) (78%), menthol (20%) and menthone (3%). Eucalyptus globulus EO caused 97% acaricidal mortality at 10% concentration. The lower concentrations reduced tick fecundity up to 90% in a dose-dependent manner. This study provides support for plant EOs as alternative tick control strategy for humans and animals.

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.

Corrigendum: Anthelmintic activity of acetone extracts from South African plants used on egg hatching of Haemonchus contortus.

No abstract available.

Corrigendum: Acaricidal activity of the aqueous and hydroethanolic extracts of 15 South African plants against Rhipicephalus turanicus and their toxicity on human liver and kidney cells.

No abstract available.

Corrigendum: Investigation of the acaricidal activity of the acetone and ethanol extracts of 12 South African plants against the adult ticks of Rhipicephalus turanicus.

No abstract available.

Tramadol improved the efficacy of ketamine-xylazine anaesthesia in young pigs.

OBJECTIVE: To evaluate the influence of premedication with tramadol on xylazine-ketamine anaesthesia in young pigs. STUDY DESIGN: Prospective, randomized, blinded cross-over study. ANIMALS: Ten young Niger hybrid pigs: mean weight 6.1 +/- 0.6 kg. METHODS: Pigs were anaesthetized twice. Xylazine (2.5 mg kg(-1)), ketamine (25 mg kg(-1)) and atropine (0.04 mg kg(-1)) were administered by intramuscular (IM) injection, 5 minutes after either tramadol (5 mg kg(-1))) (treatment XKT) or saline (treatment XKS). Time to loss of righting reflex (TLRR), duration of antinociception, duration of recumbency (DR) and recovery times (RCT) were recorded. Quality of induction of anaesthesia including ease of endotracheal intubation was assessed using a subjective ordinal rating score of 1 (worst) to 4 (best). Heart, pulse and respiratory rates, arterial oxygen saturations and rectal temperatures were determined over 60 minutes. Antinociception was assessed by the pigs' response to artery forceps applied at the interdigital space. Data were compared with Student's t-test, Mann-Whitney's test or analysis of variance (anova) for repeated measures as appropriate and are presented as mean +/- standard deviation. RESULTS: The quality of anaesthetic induction was significantly better and duration of antinociception significantly longer (p < 0.05) in treatment XKT (3.1 +/- 0.7 score; 43.7 +/- 15.5 minutes) than in treatment XKS (2.8 +/- 0.6 score; 32.0 +/- 13.3 minutes). TLRR, DR and RCT did not differ significantly (p > 0.05) between treatment XKT (2.1 +/- 0.8, 65.8 +/- 17.0 and 13.2 +/- 6.7 minutes) and treatment XKS (2.1 +/- 1.3, 58.0 +/- 14.8 and 10.3 +/- 5.6 minutes). Physiological measurements did not differ between the treatments. CONCLUSION AND CLINICAL RELEVANCE: Tramadol improved the quality of anaesthetic induction and increased the duration of antinociception in xylazine-ketamine anaesthetized young pigs without increasing duration of anaesthesia, nor causing additional depression of the physiological parameters measured.

Acaricidal activity of the aqueous and hydroethanolic extracts of 15 South African plants against Rhipicephalus turanicus and their toxicity on human liver and kidney cells.

Hot water and hydroethanolic (70:30) extracts were prepared from 15 plant species, which were investigated to discover eco-friendly and less expensive tick control methods as an alternative to synthetic acaricides. A contact bioassay was used to determine the acaricidal activity of these extracts against the cattle tick, Rhipicephalus turanicus (Acari: Ixodidae) at a concentration of 20% (200 mg/mL). The hydroethanolic extracts had better activity than the hot water extracts against R. turanicus. The hydroethanolic extract from Tabernaemontana elegans (leaves) had the best mortality (87.0%). This was followed by Calpurnia aurea (stems) with a mortality of 75.0%, Schkuhria pinnata (whole plant) with a mortality of 67.0% and Aloe rupestris (leaves) with a mortality of 66.6%. The toxicity of the plant extracts was also investigated and it was found that most of the hydroethanolic and hot water extracts were either safe or very safe on human Vero kidney and liver HepG2 cells. From this study, it was evident that botanicals have the potential to be developed as environmentally benign natural acaricides against R. turanicus.

Further studies on South African plants: Acaricidal activity of organic plant extracts against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

The goal of our research is to develop a lower cost eco-friendly tick control method because acaricides that are commonly used to control ticks are often toxic, harmful to the environment or too expensive for resource-limited farmers. Acetone and ethanol extracts were prepared and their acaricidal activities determined against the southern cattle tick, Rhipicephalus (Boophilus) microplus. A 1% solution of each of the plant extracts was prepared for efficacy testing using the adapted Shaw Larval Immersion Test (SLIT). The acetone stem extract from Cissus quadrangularis (Vitaceae) and the ethanol leaf and flower extract from Calpurnia aurea (Fabaceae) had potent activity like that of the commercial acaricide, chlorfenvinphos [corrected mortality (CM)=100.0%]. The ethanol extracts of the stem of C. quadrangularis (CM=98.9%) and that of the roots, leaves and fruit of Senna italica subsp arachoides (CM=96.7%) also had good acaricidal activity. There is potential for the development of botanicals as natural acaricides against R. (B.) microplus that can be used commercially to protect animals against tick infestation. Further studies to isolate the acaricidal active compounds and to determine the environmental fate, species toxicity and skin toxicity of these plants species are, however, required before they can be considered as a treatment against ticks.

Investigation of the acaricidal activity of the acetone and ethanol extracts of 12 South African plants against the adult ticks of Rhipicephalus turanicus.

The acaricidal activity of acetone and ethanol extracts of 12 plant species was evaluated using the contact method on Rhipicephalus turanicus (Acari: Ixodidae) ticks at an initial concentration of 20% (200 mg/mL). Eight of the 12 plants had mortality greater than 50% and the acetone extracts had better acaricidal activity than the ethanol extracts. The acetone extract of Calpurnia aurea (leaves and flowers) had the highest corrected mortality (CM) of 92.2% followed by Schkuhria pinnata (whole plant) with a CM of 88.9%, Ficus sycomorus (bark and stems) 86.7% and Senna italica subsp. arachoides (roots, leaves and fruits) 83.3%. Selected extracts were tested at five different concentrations using the adult immersion test. From dose-response assays, EC₅₀ values of 61.82 mg/mL, 115.21 mg/mL and 161.02 mg/mL were obtained for the acetone extracts of S. pinnata (whole plant), S. italica subsp. arachoides (roots, leaves and fruits) and C. aurea (leaves and flowers) respectively. The ethanol extract of Monsonia angustifolia (whole plant) had the highest CM of 97.8% followed by S. pinnata (whole plant) with a CM of 86.7%, C. aurea (leaves and flowers) 81.1% and Cleome gynandra (leaves) 77.8%. There is potential for the development of environmentally benign botanicals as natural acaricides against R. turanicus.

Acaricidal activity of the organic extracts of thirteen South African plants against Rhipicephalus (Boophilus) decoloratus (Acari: Ixodidae).

The African blue tick, Rhipicephalus (Boophilus) decoloratus, is a common tick species found in South Africa and affects cattle production as well as vectoring pathogens in regions of Africa and Asia. In an attempt to develop a non-toxic, lower cost and environmentally friendly tick control method, twenty-six plant extracts were prepared from thirteen plant species using 99.5% acetone and 99% ethanol. The adapted Shaw Larval Immersion Test (SLIT) was used to test the efficacy of the extracts. A 1% solution of each of the plant extracts was prepared for efficacy testing and the ethanol extracts were found to have better acaricidal activity than the acetone extracts. The ethanol extract from the leaves and flowers of Calpurnia aurea had the best activity [corrected mortality (CM)=82.9%] which was followed by the stem extract of Cissus quadrangularis (CM=80.4%). The plant species were screened against Vero cells and were found to have low toxicity. From this study it is apparent that there is potential for the development of botanicals as natural acaricides against R. (B.) decoloratus.

Anthelmintic activity of acetone extracts from South African plants used on egg hatching of Haemonchus contortus.

The nematode, Haemonchus contortus, is responsible for major economic losses in the livestock industry. The management of parasites such as H. contortus has been through the use of synthetic parasiticides. This has resulted in the presence of residues in meat and milk, which affects food safety. The development of resistance to available anthelmintics coupled with their high cost has further complicated matters. This has led to the investigation of alternative methods to manage nematodes, including the use of plants and plant extracts as a potential source of novel anthelmintics. Acetone extracts were prepared from 15 South African plant species and their anthelmintic activity determined using the egg hatch assay (EHA). The leaf extract of Cleome gynandra had the best inhibitory activity (68% ± 3%) at a concentration of 2.5 mg/mL, followed by the stem extract of Maerua angolensis (65% ± 5%). The extracts had a relatively low toxicity on Vero cells determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) cellular assay.

Anti-inflammatory and analgesic effects of methanol extract and fractions of Acalypha wilkesiana leaves.

BACKGROUND: This study was carried out to evaluate the anti-inflammatory and the analgesic potentials of Acalypha wilkesiana leaf extract in experimental animals. METHODS: The anti-inflammatory potential was investigated using an acute rat model. Aspirin at 150 mg/kg, indomethacin at 10 mg/kg as positive control, and methanolic extracts and solvent fractions of A. wilkesiana at doses of 400 and 200 mg/kg, respectively, were administered orally to rats and compared with a negative control group given 10 mL/kg Tween 80. At an A. wilkesiana dose of 400 mg/kg body weight, the analgesic effect was also studied using the hot plate method and the acetic acid-induced writhing model in mice. RESULTS: Percentage inhibition of the paw volume was highest in rats administered indomethacin (85.7%) followed by the group administered methanolic extract of A. wilkesiana (74.1%), whereas the group given aspirin had 65.5% inhibition of edema and the group given a 200 mg/kg dose of chloroform fraction of A. wilkesiana had 93% inhibition of increase in paw volume, a value higher than the performance of the standard drugs indomethacin (85%) and aspirin (68%). Also, the extract caused an increase in the reaction time in the hot plate test and in the acetic acid test. The mean number of writhings was significantly reduced in the group of mice administered 400 mg/kg extract of A. wilkesiana leaves (25.8±1.3) when compared with the control (46.7±1.4) but higher than the group of mice administered the standard analgesic agent paracetamol (23.5±1.3). CONCLUSIONS: This study suggested that A. wilkesiana leaves have anti-inflammatory and analgesic potential comparable with those of standard drugs.

Descriptive analyses and risk of death due to Ebola Virus Disease, West Africa, 2014.

INTRODUCTION: Since the first case of Ebola virus disease (EVD) in Guinea in 2013, major outbreaks have been reported in West Africa. METHODOLOGY: Cases and fatalities of EVD caused by Zaire Ebola virus (ZEBOV) were evaluated, and the risks of dying in the general population and in healthcare workers were assessed. RESULTS: The case fatality rate estimated for EVD was 76.4% in 20 studies. Cumulative proportion of fatal cases in West Africa was 42.9%, 30.1%, and 64.2% in Liberia, Sierra Leone, and Guinea, respectively. The proportion of total deaths in Liberia, Sierra Leone, and Guinea was 42.5%, 35.8%, and 21.6%, respectively. Healthcare workers were at higher risk of dying compared with the general public, and the same applied to intense transmission countries and to countries with sufficient bed capacities. The declaration of a health emergency "out-of-control" situation by the World Health Organization on 8 August 2014 reduced the risk of death among patients. Factors including deplorable healthcare delivery infrastructure in war-ravaged regions of Africa, the impotence of governments to enforce public health regulations, and the loss of confidence in public healthcare delivery programs were key among others factors that enhanced the spread and magnitude of outbreaks. CONCLUSIONS: The findings underscore the need for an overall re-appraisal of the healthcare systems in African countries and the ability to cope with widespread epidemic challenges. Outbreaks like that of Ebola diseases should be handled not just as a medical emergency but also a socio-economic problem with significant negative economic impacts.