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Nutritional Management of Hyperlipaemia

Citation

Andy Durham, Alexandra K. Thiemann. May 2015. Nutritional Management of Hyperlipaemia. Equine Veterinary Education.

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Publication date: 
26 May 2015
DOI number: 
10.1111/eve.12366
Abstract

Hyperlipaemia is a disease resulting from excessive mobilisation of triglyceride stores such that plasma clearance processes become overwhelmed. Consequently increased plasma triglyceride concentrations (>5.6 mmol/l), visibly cloudy plasma and a sick, anorexic or hypophagic subject follow. Epidemiological studies have identified many predisposing and triggering factors and the attentive carer or veterinary surgeon should be alert to such risk factors so that the disease can be prevented, or at least identified and treated at an early stage. Hyperlipaemic subjects are invariably in a negative energy balance, and nutritional management therefore plays a central role in both the prevention and resolution of the disease.

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A Potential Novel Anthelmintic? The Cysteine Proteases Show Potent Anthelmintic Activity Against Cyathostomins In Vitro

Citation

Laura Peachey, Jacqui. B. Matthews, Gina L. Pinchbeck, J. Benkhe, Faith A. Burden, Jane Hodgkinson. September 2014. A Potential Novel Anthelmintic? The Cysteine Proteases Show Potent Anthelmintic Activity Against Cyathostomins In Vitro. Equine Veterinary Journal. 46. 23.

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Publication date: 
8 September 2014
Volume: 
46
Page numbers: 
23
DOI number: 
10.1111/evj.12323_52
Abstract

Reasons for performing study
Anthelmintic resistance is a global problem and constitutes a major threat to the welfare of equids worldwide. The cyathostomins are the most numerous and pathogenic gastrointestinal nematode (GIN) of equids in the developed world. Cyathostomins show widespread resistance to 2 out of 3 of the major classes of anthelmintic and recently there are reports of reduced efficacy to the potent macrocyclic lactones (MLs). None of the 3 novel classes of anthelmintic that have emerged in the last decade are licensed for use in equids. The cysteine proteases (CPs) are plant proteins that have shown potent activity against GINs in vivo in sheep and pigs.

Objectives
This study aimed to evaluate the anthelmintic effect of the CP papain on cyathostomins in vitro using the egg hatch assay (EHA) and larval migration inhibition test (LMIT).

Methods
Samples of cyathostomin eggs and third stage larvae were collected and cultured from a population of equids that have recently shown reduced ML efficacy in vivo. The EHA and LMIT were performed on repeated samples with increasing concentrations of papain. Dose–response curves were plotted and PROBIT analysis performed on the data to give EC-50 values (concentration that gives 50% of the maximal response).

Results
Papain caused a dose dependent inhibition of both egg hatch and larval migration. The EC-50 values were 2 μmol/l and 100 μmol/l in the EHA and LMIT respectively, indicating a more potent effect on egg hatch.

Conclusions
The CP papain shows potent anthelmintic activity against cyathostomins in vitro. Good evidence of anthelmintic effect against GINs in other host species is supportive of its potential use in equids. Further work is indicated to evaluate safety and in vivo efficacy.

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An evidence-based approach to the evaluation of ethnoveterinary medicines against strongyle nematodes of equids

Citation

Laura Peachey, Gina L. Pinchbeck, Jacqui. B. Matthews, Faith A. Burden, Mulugeta Getachew, Claire Scantlebury, Jane Hodgkinson. March 2015. An evidence-based approach to the evaluation of ethnoveterinary medicines against strongyle nematodes of equids. Veterinary Parasitology.

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Publication date: 
25 March 2015
Abstract

Cyathostomins are the most important gastrointestinal nematode infecting equids. Their effective control is currently under threat due to widespread resistance to the broad spectrum anthelmintics licenced for use in equids. In response to similar resistance issues in other helminths, there has been increasing interest in alternative control strategies, such as bioactive plant compounds derived from traditional ethnoveterinary treatments. This study used an evidence-based approach to evaluate the potential use of plant extracts from the UK and Ethiopia to treat cyathostomins. Plants were shortlisted based on findings from a literature review and additionally, in Ethiopia, the results of a participatory rural appraisal (PRA) in the Oromia region of the country. Systematic selection criteria were applied to both groups to identify five Ethiopian and four UK plants for in vitro screening. These included Acacia nilotica (L.) Delile, Cucumis prophetarum L., Rumex abyssinicus Jacq., Vernonia amygdalina Delile. and Withania somnifera (L.) Dunal from Ethiopia and Allium sativum L. (garlic), Artemisia absinthium L., Chenopodium album L. and Zingiber officinale Roscoe. (ginger) from the UK. Plant material was collected, dried and milled prior to hydro-alcoholic extraction. Crude extracts were dissolved in distilled water (dH2O) and dimethyl sulfoxide (DMSO), serially diluted and screened for anthelmintic activity in the larval migration inhibition test (LMIT) and the egg hatch test (EHT). Repeated measures ANOVA was used to identify extracts that had a significant effect on larval migration and/or egg hatch, compared to non-treated controls. The median effective concentration (EC-50) for each extract was calculated using PROBIT analysis. Of the Ethiopian extracts A. nilotica, R. abyssinicus and C. prophetarum showed significant anthelmintic activity. Their lowest EC-50 values were 0.18 (Confidence interval (CI): 0.1-0.3), 1.1 (CI: 0.2-2.2) and 1.1 (CI: 0.9-1.4) mg/ml, respectively. All four UK extracts, A. sativum, C. album, Z. officinale and A. absinthium, showed significant anthelmintic activity. Their lowest EC-50 values were 1.1 (CI: 0.9-1.3), 2.3 (CI: 1.9-2.7) and 0.3 (CI: 0.2-0.4) mg/ml, respectively. Extract of A. absinthium had a relatively low efficacy and the data did not accurately fit a PROBIT model for the dose response relationship, thus an EC-50 value was not calculated. Differences in efficacy for each extract were noted, dependent on the assay and solvent used, highlighting the need for a systematic approach to the evaluation of bioactive plant compounds. This study has identified bioactive plant extracts from the UK and Ethiopia which have potential as anthelmintic forages or feed supplements in equids.

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Essential oils in the management of the donkey louse, Bovicola ocellatus

Citation

Lauren Ellse, Bryony Sands, Faith A. Burden, Richard Wall. March 2015. Essential oils in the management of the donkey louse, Bovicola ocellatus. Equine Veterinary Journal.

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Publication details
Publication date: 
10 March 2015
DOI number: 
DOI: 10.1111/evj.12431
Abstract

REASONS FOR PERFORMING THE STUDY:
Chewing lice are widespread and clinically compromising parasites of livestock and equines. Their management is complicated by growing levels of resistance to commonly applied insecticides. Hence, the development of novel approaches to their control is of major clinical interest.
OBJECTIVES:
To assess the effects of incorporating the essential oils of tea tree and lavender into a grooming programme for populations of donkeys with natural infestations of Bovicola ocellatus in the UK and Ireland when louse populations were at their winter seasonal peak.
STUDY DESIGN:
In vivo field trial.
METHODS:
Suspensions of 5% (v/v) tea tree or lavender oil or an excipient only control, were groomed into the coats of winter-housed donkeys (n = 198) on 2 occasions, 2 weeks apart. Louse counts were conducted before each application and 2 weeks later.
RESULTS:
After 2 applications, the groups groomed with lavender or tea tree oil suspensions had a significant reduction in louse intensity, with a mean decline in louse abundance of 78% (95% CI 76-80%). Louse numbers in the groups groomed with excipient only either did not change or increased significantly. Donkey hair length had no effect on the decline in louse numbers.
CONCLUSIONS:
These results demonstrate that the inclusion of essential oil suspensions during grooming can be used to manage louse populations successfully. This article is protected by copyright. All rights reserved.

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Quantifying the effects of individual animal characteristics and climatological factors on faecal worm egg count shedding in donkeys

Citation

Christopher J Corbett, Sandy Love, Giles T. Innocent, Ian McKendrick, Jacqui. B. Matthews, Faith A. Burden, Matthew Denwood. Quantifying the effects of individual animal characteristics and climatological factors on faecal worm egg count shedding in donkeys. Presented at British Society for Parasitology Spring Meeting.

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Presentation details
Date presented: 
Monday 7 April 2014
Abstract

Cyathostomins, the predominant parasitic nematodes of equids, have developed varying degrees of resistance to all three classes of anthelmintic licensed for use in horses. It is essential that the effectiveness of alternative methods of control for these pathogens are quantified, including incorporating climatic data and the commonly advocated practice of removal of faeces from pasture. Here, we obtained monthly faecal worm egg counts (FWEC, n=4,460 individual counts) from 803 donkeys based at The Donkey Sanctuary (Devon, UK). The dataset also included age, sex, field, FWEC history and previous anthelmintic administrations in each individual, as well as the pasture hygiene management method applied in the field where the donkey was grazed. FWEC were analysed alongside local climatic data using a generalised linear mixed model to assess associations between these variables and each observed monthly FWEC. The preferred model was identified using a model selection algorithm based on penalised likelihoods, and associated a 2.1% decrease in FWEC per day with air frost two calendar months ago (p<0.001) and a 38% lower FWEC in groups with twice weekly manual faecal removal compared to those with no faecal removal (p=0.004). Other weather effects, both alone and as interaction terms with the average FWEC of the field were included in the model, alongside individual FWEC history with anthelmintic administration as interaction terms and date as a single term. Our study identifies factors that may be useful as part of on-going predictive modelling based methods of improving targeted selective therapy.

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Pyrantel resistance in two herds of donkey in the UK

Citation

Edwina Lawson, Faith A. Burden, Hany Elsheikha. January 2015. Pyrantel resistance in two herds of donkey in the UK. Veterinary Parasitology.

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Publication date: 
7 January 2015
DOI number: 
10.1016/j.vetpar.2014.12.026
Abstract

Resistance to currently available anthelmintics is a serious phenomenon which is prevalent globally. Cyathostomins are one of the major parasites, and are of primary concern in donkeys. There have been reports of emerging resistance to pyrantel, but the status of pyrantel resistance in donkey populations in the UK is largely unknown. This report investigates pyrantel resistance in two geographically isolated donkey herds in the South West of England. The first herd had suspected pyrantel resistance, with already established resistance to other anthelmintics. In the second herd the efficacy of pyrantel was not suspected at the time the study took place. Faecal Egg Count Reduction Test (FECRT) was carried out, revealing large scale resistance. Eighty one percent of the first herd and 73% of the second herd had a FEC of less than 95% after treatment, and anthelmintic resistance was confirmed using the World Association for the Advancement of Veterinary Parasitology guidelines. These findings indicate that anthelmintic resistance to pyrantel exists in both tested donkey populations and illustrate the continuing development of resistance through different classes of chemotherapeutics.

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Viraemic frequencies and seroprevalence of non-primate hepacivirus and equine pegiviruses in horses and other mammalian species

Citation

Sinead Lyons, Amit Kapoor, Bradley Schneider, Nathan Wolfe, Geoff Culshaw, Brendan Corcoran, Andy Durham, Faith A. Burden, Bruce McGorum, Peter Simmonds. September 2014. Viraemic frequencies and seroprevalence of non-primate hepacivirus and equine pegiviruses in horses and other mammalian species. Journal of General Virology.

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Publication date: 
5 September 2014
DOI number: 
10.1099/vir.0.065094-0
Abstract

Non-primate hepacivirus (NPHV), equine pegivirus (EPgV) and Theiler's disease associated virus (TDAV) are newly discovered members of two genera in the Flaviviridae family, Hepacivirus and Pegivirus respectively, that include human hepatitis C virus (HCV) and human pegivirus (HPgV). To investigate their epidemiology, persistence and clinical features of infection, large cohorts of horses and other mammalian species were screened for NPHV, EPgV and TDAV viraemia and for past exposure through serological assays for NPHV and EPgV-specific antibodies. NPHV antibodies were detected in 43% of 328 horses screened for antibodies to NS3 and core antibodies, of which three were viraemic by PCR. All five horses that were stablemates of a viraemic horse were seropositive, as was a dog on the same farm. With this single exception, all other species were negative for NPHV antibodies and viraemia (donkeys (n=100), dogs (n=112), cats (n=131), non-human primates (n=164) and humans (n=362). EPgV antibodies to NS3 were detected in 66.5% of horses, including 11 of the 12 horses that had EPgV viraemia. All donkey samples were negative for EPgV antibody and RNA. All horse and donkey samples were negative for TDAV RNA. By comparing viraemia frequencies in horses with and without liver disease, no evidence was obtained that supported an association between active NPHV and EPgV infections with hepatopathy. The study demonstrates that NPHV and EPgV infections are widespread and enzootic in the study horse population and confirms that NPHV and potentially EPgV have higher frequencies of viral clearance than HCV and HPgV infections in humans.

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Control of the chewing louse Bovicola (Werneckiella) ocellatus in donkeys, using essential oils

Citation

Lauren Ellse, Faith A. Burden, Richard Wall. December 2013. Control of the chewing louse Bovicola (Werneckiella) ocellatus in donkeys, using essential oils. Medical and Veterinary Entomology. 27:4. 408-413.

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Publication details
Publication date: 
1 December 2013
Volume: 
27
Issue: 
4
Page numbers: 
408-413
Abstract

Infestations by lice can be a significant clinical and welfare issue in the management of large animals. The limited range of commercial pediculicides available and the development of resistance have led to the need to explore alternative louse management approaches. The results of in vitro and in vivo trials undertaken to control populations of the donkey chewing louse, Bovicola ocellatus (Piaget) (Phthiraptera: Trichodectidae) using the essential oils of tea tree (Melaleuca alternifolia) and lavender (Lavandula angustifolia) are reported here. Results of contact and vapour bioassays showed that 5% (v/v) tea tree and lavender oils resulted in > 80% louse mortality after 2 h of exposure. On farms, separate groups of 10 donkeys sprayed with 5% (v/v) tea tree and lavender oil as part of their usual grooming regime showed significant reductions in louse numbers compared with a control group (0.2% polysorbate 80 in water). These findings indicate that tea tree and lavender essential oils can provide clinically useful levels of control of B. ocellatus when used as part of a grooming routine and suggest that with further development could form the basis of an easy to apply and valuable component of a louse management programme for donkeys.

Seasonal infestation of donkeys by lice: phenology, risk-factors and management

Citation

Lauren Ellse, Faith A. Burden, Richard Wall. April 2014. Seasonal infestation of donkeys by lice: phenology, risk-factors and management. Veterinary Parasitology.

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Publication details
Publication date: 
19 April 2014
DOI number: 
10.1016/j.vetpar.2014.04.012
Abstract

A longitudinal study was undertaken over a 21 month period to examine the seasonal abundance of lice infesting donkeys, the risk factors which predispose donkeys to infestation and the effectiveness of louse management. All the lice seen were Bovicola (Werneckiella) ocellatus. A strong seasonal pattern, which was correlated with mean monthly temperature, was observed with higher prevalence and intensity in the cooler, winter months (October-March). Overall infestation in these animals was over-dispersed, suggesting that some individuals are strongly predisposed to infestation. Donkey age and mean hair length were characteristics which affected louse prevalence: older and younger donkeys and donkeys with longer hair harboured the highest numbers of lice. However, the practice of coat-clipping, to reduce the infestation, resulted in a lower louse prevalence only in the summer, suggesting that clipping is not an effective form of louse control in cooler months. Higher louse burdens were associated with larger areas of visible excoriation and hair damage, suggesting that B. ocellatus does adversely impact animal welfare. However, the ability of animal carers to estimate louse presence or absence accurately on an individual donkey was not sufficiently high to allow targeted selective treatment of heavily infested animals to be employed effectively. As animals are housed in closed herds these findings suggest that clipping in the summer and treating all animals with insecticide in late autumn, prior to turn-in may be an effective louse management strategy.

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