pathology

Retrospective analysis of post-mortem findings in 1,444 aged donkeys

The aim of this study was to describe and report the prevalence of conditions found at necropsy examination of UK donkeys. Records from 1,444 donkeys over a 7-year period were included in the analysis. Sixty-one categories of post-mortem finding were identified from 9,744 observations. The four most prevalent conditions noted were dental disorder (78.7%), vascular disease other than aneurysm (60.9%), arthritis (55.4%) and foot disorder (44.8%). Gastric ulceration was found in 42% of the donkeys and gastrointestinal impaction in 18.6%. The most frequent combination of two post-mortem findings in the same animal was arthritis and dental disorder. The most common disorders were associated with age, body weight and/or body condition post mortem and, for some disorders, gender. For many of the post-mortem findings, crude associations were found between the presence of one finding and the odds of also having certain other post-mortem findings. This study is the first to summarize all conditions noted at necropsy examination for a large group of donkeys. The findings increase knowledge of diseases and conditions of this species and may be useful when investigating the relevance of various pathological conditions in the live animal.

Volume
144
Issue
2-3
Start page
145
End page
156
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Respiratory disease in the donkey

The donkey suffers from a similar range of respiratory diseases as the horse; however, there are a number of subtle variations, knowledge of which can influence the success of treatment. As an animal adapted to a semi-arid terrain, there are variations in physiology, anatomy and disease susceptibility. The nonathletic nature of the donkey means that delayed presentation is common with many diseases and, while there may be enhanced resistance to some transboundary and parasitic diseases, there may be equal or increased severity of illness to some endemic diseases, e.g. equine influenza. Donkeys frequently live to geriatric ages and the clinician should be aware of the increased risk of conditions such as tracheal collapse, fibrosing pneumonia and neoplasia in this age group. As with any condition that causes stress and inappetance, respiratory disease in the donkey may be complicated by hyperlipaemia and good nursing care is an essential component of treatment.

Volume
24
Issue
9
Start page
469
End page
478
Publication date

Chronic pleuropulmonary fibrosis and elastosis of aged donkeys - similarities to human pleuroparenchymal fibroelastosis (PPFE)

Donkey Pulmonary Fibrosis (DPF) is a spontaneous syndrome of aged donkeys with high prevalence (35%). No previous detailed characterisation of DPF has been performed. We sought to determine the similarities of DPF to recognised patterns of human pulmonary fibrosis.

Whole lungs were collected from 32 aged donkeys at routine necropsy. Gross examination revealed pulmonary fibrosis in 19 donkeys (DPF cases), while 13 (controls) had grossly normal lungs. Eighteen whole inflated ex vivo lungs (11 DPF, 7 controls) were imaged with high resolution computed tomography (HRCT), while the remainder were sectioned and photographed. Tissue samples were collected from all lungs for histopathological evaluation using a standardised protocol. HRCT images and histology sections were reviewed independently and blindly. Lung tissue was analysed for herpes virus, fungal hyphae, mycobacteria and dust content.

Ten of 19 DPF lungs were categorised as being 'consistent with' pleuroparenchymal fibroelastosis (PPFE) according to previously defined histological and imaging criteria. All 10 PPFE-like lungs had marked pleural and subpleural fibrosis, predominantly within the upper lung zone, with accompanying intra-alveolar fibrosis and elastosis. Asinine herpesvirus (AsHV) was ubiquitously expressed within control and DPF lung tissue. No other aetiological agents were identified.

Many cases of DPF share key pathological and imaging features with human PPFE, a rare interstitial pneumonia. Consequently, further study of DPF may help elucidate the aetiopathogenesis of human PPFE.

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Assessment of cardiovascular disease in the donkey: clinical, echocardiographic and pathological observations

The Donkey Sanctuary (DS) owns 3500–4000 donkeys, estimated to be about 35 per cent of the UK population. Although postmortem surveys suggest a high prevalence of cardiovascular disease in donkeys, there is sparse clinical information about cardiovascular examination findings and echocardiographic findings in health and disease. In this cross-sectional study, auscultation findings were recorded, and in a subset of donkeys, echocardiography was used to screen for structural and functional cardiac disease. 202 donkeys were examined; 117 geldings and 85 females. Heart sounds S1 and S2 were detected in all donkeys, but none had audible S3. S4 was detected in nine (4.5 per cent; significantly older than those without S4; P<0.001). A heart murmur was detected in four donkeys. Echocardiography identified these to be due to a ventricular septal defect in one, and aortic regurgitation in three. An additional 43 donkeys had echocardiography. A further 10 donkeys were identified to have aortic insufficiency, but no other valvular regurgitation. 76/202 donkeys subsequently underwent postmortem examination. Three showed degenerative aortic valve changes. One donkey had nodular lesions in the intima of proximal aorta and sinus of Valsalva. Histopathology showed multifocal chronic nodular eosinophilic arteritis, consistent with verminous arteritis. The Donkey Sanctuary pathology database identified other similar cases.

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Mycobacterium bovis infection in a donkey

Jill Bryan
Pieter Den Boon
J. McQuirk
G. Madigan
Ursula Fogarty
Presentation date

Introduction

Mycobacterial infections are rare in equines. Mycobacterium bovis (M. bovis) is an important zoonotic pathogen causing disease in a wide range of animal species. Infection with M. bovis has not been documented previously in the donkey.

Materials and Methods

A 29-year-old donkey gelding presented with depression, pyrexia, tachycardia, tachypnoea and generalised wheezes and crackles on thoracic auscultation. Haematologic examination identified neutrophilic leukocytosis. Response to treatment with antimicrobials and non-steroidal anti-inflammatories was poor and the donkey was euthanased.

Results

On gross postmortem examination the lungs were diffusely consolidated with an irregular nodular appearance of the surface and multiple coalescing, firm, pale masses diffusely distributed throughout the parenchyma. Multiple, variably sized, firm, pale nodular masses were also identified within the mediastinum, epicardium, omentum, kidneys, liver, spleen and diaphragm. Histopathological examination of lung showed prominent interstitial fibrosis and diffuse granulomatous inflammation in which acidfast bacilli were occasionally identified. The additional nodular masses represented foci of chronic granulomatous inflammation. Culture of lung yielded a heavy growth of mycobacteria confirmed to be M. bovis by molecular techniques (GenoType MTBC).

Conclusion

Although rare in equines, disease caused by M. bovis should be considered as a possible differential diagnosis in donkeys presenting with signs of respiratory disease and respiratory or generalised granulomatous inflammation.

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