donkey

Besnoitiosis in a european donkey

Citation

Cynthia de Vries, A. Santi, Karen Rickards, G. Loesenbeck. Besnoitiosis in a european donkey. Presented at ECVP Annual Meeting 2016.

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Presentation details
Date presented: 
Wednesday 7 September 2016
Event name: 
ECVP Annual Meeting 2016
Abstract

Introduction: A 3-year-old castrated male donkey was presented with multifocal, moderately firm, dull, white nodules, varying in size from 0.5-2.0 cm in diameter. The nodules were located on the skin of the penile shaft and showed depigmentation. Other locations on the body were not involved.

Materials and Methods: Surgical excision of the nodules was performed. All formalin-fixed samples were embedded in paraffin and routinely processed for histopathological examination.

Results: Histopathological examination revealed presence of multifocal, round to oval, protozoal cysts within the dermis, with a size of 150-500 μm. The mature cyst walls consisted of four distinct layers, including an outer, hyalinized, eosinophilic layer of collagen fibers, a thin homogenous intermediate layer, a layer consisting of the cytoplasm of the host fibroblast with a compressed nucleus, and an inner layer that formed the parasitophorous vacuole. The vacuole was filled with numerous bradyzoites of 2 x 8 μm. There was a mild to moderate, superficial to mid-dermal infiltration of lymphocytes, plasma cells, macrophages and eosinophils, surrounding the cysts and blood vessels. The hair follicles were atrophic. The overlying epidermis showed mild acanthosis and orthokeratotic hyperkeratosis. Based on the histopathological findings, a diagnosis of Besnoitia sp. infection was made.

Conclusions: Besnoitiosis is an emerging disease in cattle in Europe. Few outbreaks have been reported in donkeys in the USA. To our knowledge, this is the first report in the literature of Besnoitia sp. infection in an European donkey.

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Efficacy of anthelmintics in horses and donkeys in Ireland: An in vivo and in vitro study

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Authors
Presentation details
Date presented: 
Friday 3 June 2016
Abstract

Strongyles are the most important parasite group infecting equids. Management of these parasites has relied on intensive use of anthelmintics, however, resistance has developed against all drug classes and is becoming a major practical problem in many countries. Resistance to the benzimidazole (BZ) group is geographically widespread and resistance to pyrental has also been reported. Today the macrocyclic lactones (ML) class of drugs has become the most commonly used drug, but evidence of emerging resistance (i.e. shortened egg reappearance period (ERP)) has been identified in many countries. A variety of tests are available to monitor anthelmintic efficacy but most of them are expensive, laborious and time consuming. The aim of this project was to determine the efficacy of anthelmintic drugs used in eight equine groups in Ireland. The anthelmintic efficacy was determined by calculating the percentage reduction in the faecal egg count (FEC) between the group mean at Day 0 and Day 14 post-treatment (FECRT). In addition FECs were also calculated at two week intervals for up to 16 weeks after anthelmintic drug administration to determine the ERP for BZ, ivermectin and moxidectin. ERP was defined when the group arithmetic mean FEC exceeded 10% of the group arithmetic mean FEC at Day 0.The larval development assay (LDA) was used to detect resistance to BZ in two groups of horses and the larval migration inhibition assay (LMIA) was also performed to measure the sensitivity to ivermectin in two groups of donkeys and moxidectin in two horse farms and two groups of donkeys. The results of FECRT indicate BZ-resistance on both farms; FECR of 86% and 61%, an ERP of only two weeks and the EC50 for the LDA of 0.3 and 0.7 µg/ml, respectively. While MLs were still effective in all cases with a FECR >95% and the EC50 for the LMIA ranging from 0.06 to 0.38 µg/ml the ERP ranged from only 4 to 10 weeks. Overall the results from this study indicate that BZ was ineffective but both ivermectin and moxidectin are still effective in all groups. However, the reduced ERP results for the MLs would suggest that these products are less effective compared to label claims - a shortened ERP is believed to be an early indicator of resistance.

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Donkeys - a unique and challenging endoparasite host

Citation

Faith A. Burden, Mulugeta Getachew. April 2016. Donkeys - a unique and challenging endoparasite host. Journal of Equine Veterinary Science. 39:Supplement. S102-S103.

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Publication date: 
5 April 2016
Volume: 
39
Issue: 
Supplement
Page numbers: 
S102-S103
DOI number: 
10.1016/j.jevs.2016.02.216
Abstract

Endoparasites in donkeys are ubiquitous and may cause serious disease. All common helminth parasites that affect horses also infect donkeys, therefore donkeys that co-graze can act as a significant source of infection for either species. Whilst donkeys are prone to the same parasite species as horses infection characteristics and presenting signs and symptoms of disease may differ. Large strongyles and cyathostomins are common in donkeys worldwide with Strongylus vulgaris causing significant disease in donkeys with poor anthelmintic treatment history. Cyathostomins infect the majority of donkeys globally and may rarely cause cyathostominosis or colitis; however signs and symptoms of both can vary significantly from those displayed in affected horses. The significance of low level cyathostomin infection on the donkey host is unclear, many donkeys appear to thrive with high faecal egg counts (> 3000epg) and when the donkey is in general good health they may exist with high cyathostomin burdens with little impact on their overall health. The donkey is renowned as the reservoir host for the lungworm, Dictyocaulus arnfieldi. Mature horses are not permissive hosts to the full life cycle of this parasite, but develop clinical signs on infection. In contrast, donkeys are permissive hosts without displaying overt clinical signs and act as a source of infection to co-grazing horses. Donkeys are also susceptible to the flukes, Fasciola hepatica and Fasciola gigantica and may be an important reservoir host for both human and herbivore infections particularly in developing countries. Finally, Parascaris spp. infections in donkeys are common, however infection is not only associated with young, immuno-compromised animals as seen in horses. Parascaris spp. infection is a frequent finding in all age groups of donkeys. The inability of many donkeys to develop lifelong immunity to Parascaris poses problems when attempting to reduce transmission of this parasite in herds which include adult and young donkeys. Anthelmintic treatment is challenging as many anthelmintics are not licensed for use in this species; however dosing should follow best practice used in horses. Anthelmintic resistance is of particular concern in donkeys with recent reports of lack of efficacy of all anthelmintic classes in cyathostomins infecting donkeys. Control of parasites in donkeys must primarily focus on reducing the risk of infection, maintaining good health and targeting drug treatments carefully. Donkeys can be co-grazed safely with other species but careful monitoring and control should be practiced to ensure that donkeys do not act as reservoirs of infection to other, more susceptible animals. The importance of parasite infection, particularly co-infection with multiple species must be appreciated. Donkeys under stress due to malnourishment, infectious disease, overwork or neglect are at a high risk of disease related to parasite infection and consideration must be given to targeted treatments in such circumstances. Whilst the donkey remains a challenging parasite host following simple control measures and improving the overall welfare of the donkey will undoubtedly serve both the donkey and other species grazing alongside.

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Reference intervals for biochemical and haematological parameters in mature domestic donkeys (Equus asinus) in the UK

Citation

Faith A. Burden, Mulugeta Getachew, Elizabeth Hazell-Smith, Valerie Patrick, Ryan Trawford, Harriet Brooks Brownlie. November 2015. Reference intervals for biochemical and haematological parameters in mature domestic donkeys (Equus asinus) in the UK. Equine Veterinary Education.

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Publication details
Publication date: 
18 November 2015
DOI number: 
10.1111/eve.12512
Abstract

Reference intervals (RIs) for haematology and serum biochemistry for donkeys in a temperate climate have been previously published using blood sample results from the resident population of a large donkey shelter in the UK. Periodic review of reference intervals is recommended to ensure their applicability to the patient population and changes in laboratory methods and technologies. The current study aimed to revise the previously published haematology and serum biochemistry values for the adult domestic donkey (Equus asinus) in the UK in the light of a change in analytical equipment at the Donkey Sanctuary laboratory, but also to refine the demography of the sample population with respect to age, physiology and clinical history. Clinical pathology results from 138 clinically healthy mature (4–24 years inclusive) female and castrated male donkeys selected from the resident population of the Donkey Sanctuary, were analysed retrospectively. The animals were blood sampled during the period February 2008 to June 2011 as part of a routine health screen prior to rehoming. Results for a total of 38 biochemical and haematological parameters were analysed including 3 previously unreferenced parameters in addition to those assessed in the previous study. The new reference intervals and median values show very poor transferability with recently derived reference intervals for non-Thoroughbred horses and only limited transferability with reference intervals previously published for donkeys in the UK. Of particular note is a marked reduction in the upper reference limit for triglycerides of 2.8 mmol/l (from 4.3 mmol/l) since this parameter is used to decide when donkeys are at risk of developing hyperlipaemia. This study demonstrates the value of intermittent review of reference intervals and refinement of study populations. Notwithstanding the caution with which reference interval data from different laboratories should be compared, the lack of transferability of results between donkeys and horses highlights the importance of use of species-appropriate reference intervals for clinical decision-making.

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Residual and ovicidal efficacy of essential oil-based formulations in vitro against the donkey chewing louse Bovicola ocellatus.

Citation

Bryony Sands, Lauren Ellse, Richard Wall. November 2015. Residual and ovicidal efficacy of essential oil-based formulations in vitro against the donkey chewing louse Bovicola ocellatus.. Medical and Veterinary Entomology.

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Publication details
Publication date: 
2 November 2015
DOI number: 
10.1111/mve.12148
Abstract

Essential oils have shown good experimental potential as novel veterinary ectoparasiticides. However, if they are to be used as veterinary products, they must be available in formulations that are suitable for practical application against specific ectoparasites. Here, the efficacies of formulations containing 5% (v/v) lavender or tea tree oil, in combination with two emulsifiers [a surfactant, 5% (w/v) N-lauroylsarcosine sodium salt (SLS), and a soluble polymer, 5% (w/v) polyvinylpyrrolidone (PVP)], with or without 10% coconut oil, were tested in contact bioassays against the donkey chewing louse Bovicola ocellatus (Piaget) (Phthiraptera: Trichodectidae). Residual activity was quantified in open and closed containers; ovicidal efficacy was also examined. Exposure to either of 5% (v/v) lavender or tea tree oils with SLS or PVP resulted in louse mortality of 100%, but when coconut oil was included as an excipient, significantly lower efficacy was recorded. However, the formulations became significantly less effective after 2 h in open containers and 40 h in closed containers. The results confirm that the residual activity of essential oils is relatively transitory and the addition of 10% coconut oil does not prolong the period of insecticidal activity by slowing essential oil evaporation. Too short a period of residual activity is likely to be a significant impediment to the effective practical use of essential oils. However, unlike many synthetic pediculicides, the essential oils tested here were highly ovicidal, which suggests that prolonged residual activity may not be essential to kill newly hatched nymphs after treatment.

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A Neglected and Emerging Helminthosis: A Case of Equine Fasciolosis

Citation

Mulugeta Getachew, Giles T. Innocent, Stuart W. Reid, Faith A. Burden, Sandy Love. September 2015. A Neglected and Emerging Helminthosis: A Case of Equine Fasciolosis. Equine Veterinary Journal. 47:S48. 21.

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Publication details
Publication date: 
6 September 2015
Volume: 
47
Issue: 
S48
Page numbers: 
21
DOI number: 
10.1111/evj.12486_47
Abstract

Reasons for performing study
Although fasciolosis is an important livestock disease worldwide, the public health importance of human fasciolosis has increased in recent years and it is recognised as an important re-emerging zoonotic disease, its epidemiology and pathogenicity in donkeys, and the epidemiological role they may play have not been determined.

Objectives
To investigate the epidemiology and pathogenicity of fasciolosis in donkeys.

Study design
Cross-sectional coprological and retrospective post-mortem study.

Methods
Faecal samples collected from 803 randomly selected working donkeys from the central region of Ethiopia were analysed by a sedimentation-centrifugation-flotation technique. Further data on liver-flukes and associated pathologies were obtained by routine post mortem examinations of 112 donkeys, subjected to euthanasia on welfare grounds or died. Data were analysed using a generalised linear model and multivariate binary logistic regression in R statistical package with significance level of statistical tests set at P<0.05.

Results
Infection prevalences of 44.4% and 41.9% were obtained in coprologically and post mortem examined donkeys, respectively, irrespective of their age. Both Fasciola hepatica and Fasciola gigantica were identified with the mean infection intensity of 30 flukes. Older donkeys (≥8 years) were found harbouring a significantly higher worm burden (P<0.0001). Gross and histopathologies of hyperplasia and thickening of the bile ducts, fibrosis of large portal areas and irregular bile duct proliferation and hypertrophy were noted.

Conclusions
The high infection prevalence of fasciolosis and the associated hepatic pathologies in working donkeys shows not only the susceptibility of donkeys and the impact it has on their health, but also indicates the important role they can play in the epidemiology of both livestock and human fasciolosis. These further demonstrate the need for these animals to be considered in the overall epidemiological studies and for sound control strategies and prevention of fasciolosis.

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An investigation of the equine infectious disease threat represented by the presence of donkeys at mixed equestrian events in Ireland

Citation

Sarah Finney, Joseph A. Collins, Vivienne Duggan. July 2015. An investigation of the equine infectious disease threat represented by the presence of donkeys at mixed equestrian events in Ireland. Irish Veterinary Journal. 68:11.

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Publication details
Publication date: 
1 July 2015
Volume: 
68
Issue: 
11
DOI number: 
10.1186/s13620-015-0041-6
Abstract

The number of abandoned or otherwise neglected donkeys has significantly increased in Ireland in the recent past. The real or perceived capacity of the donkey to act as a reservoir of equine infectious disease, and thus pose an increased risk of disease transmission to horses and ponies, may be a factor in this increased abandonment and neglect. The authors here report on a field study exploring the infectious disease transmission threat the donkey poses to the general equine industry in Ireland through an examination of biosecurity standards and the views of horse and donkey exhibitors at nine mixed equestrian events in 2014. Quantitative information was gathered via the organising committee (if any) and through an examination of facilities and procedures. Qualitative information was gathered using a semi-structured questionnaire to ascertain the view of exhibitors regarding the keeping of donkeys and any infectious disease transmission risks posed.

Results
At eight of nine events visited there were no entrance controls, no veterinary examinations, no enforcement of legislation regarding equine identification and equine premises registration and no isolation facilities on site for equids. Contact between donkeys and other equids was largely uncontrolled. Exhibitors had travelled from abroad to one event. Exhibitors generally opined that they did not perceive the donkey to represent any additional infectious disease transmission threat above that posed by other equids; there was however a general sense that donkeys were less well regarded for other reasons including nuisance and uselessness.

Conclusions
When biosecurity controls are not in place (or enforced) to actually check passports, verify identification and equine premises registration, mixed equestrian events may unwittingly act as the mechanism of spread of endemic and potentially more seriously exotic equine infectious disease. Donkeys were not generally considered by equine exhibitors at mixed events in Ireland to represent a heightened reservoir of disease or to pose an increased risk of transmission of contagious disease suggesting that other factors should be considered more important when studying the incidence of abandonment and neglect.

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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 details
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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