Wildlife Medicine and Rehabilitation

Self-Assessment Color Review

Anna Meredith, Emma Keeble

• Publisher: CRC Press
• Year: 2011
• Print ISBN: 9781840761467
• eBook ISBN: 9781482261592
• Edition: 1
• Topic: Medicine
• Subtopic: Veterinary Medicine

Veterinarians increasingly encounter wildlife casualties in practice and have a duty of care for the welfare of the animals. This comprehensive and easy-to-use self assessment book contains some 208 clinical cases with 325 illustrations. It has been compiled by authors with a wide range of experience and expertise in this area. Common conditions se

Self-Assessment Colour Review Wildlife Medicine & Rehabilitation

1, 2: Questions

1 A four-month-old greater flamingo presented with a lesion involving the dorsal eyelid (1). The bird was housed outside in a park with a group of 20 other chicks of similar age. A further four chicks had similar lesions on the non-feathered skin of their hock joints or on the feathered part of their necks.

i. List the differential diagnoses for these lesions.

ii. What are the diagnostic test(s) to determine a provisional diagnosis and to confirm the diagnosis?

iii. What therapeutic and surgical considerations are there, and what is the prognosis in this case?

iv. What preventive measures can be taken to avoid this condition?

2 An orphaned juvenile red squirrel develops pale yellow diarrhoea while being hand-reared (2a). Direct microscopy (×100) of a faecal smear reveals a few small oval structures (2b).

i. What is the organism shown?

ii. Is this likely to be causing the diarrhoea?

iii. What factors could be contributing to the diarrhoea and how could these be reduced?

1, 2: Answers

1 i. Mosquito bites, mite infestations, haematomas, early abscesses, avipox infection, mycobacteriosis, neoplasia. This was a case of cutaneous avipox.

ii. A provisional diagnosis can be made based of clinical signs. A definitive diagnosis is made histopathologically, with examination of biopsy samples and demonstration of typical intracytoplasmic inclusions or Bollinger bodies. Virus isolation using biopsy samples is possible using the chorioallantoic membrane of embryonated chicken eggs. Electron microscopy is important because it is not always possible to isolate virus from dry scabs.

iii. There is no specific treatment. Secondary infection with bacteria or fungi may be treated with broad-spectrum antibacterial or antifungal therapy. Supplementation with vitamin A to promote epithelial regeneration and topical anti-bacterial/antifungal creams or mercurochrome may be helpful. Hydrocolloid or hydroactive dressings will aid skin healing. Electrocautery and chemical cautery using silver nitrate pencils can be used to treat cutaneous lesions. Large proliferative lesions may need to be surgically excised. In mild cases the prognosis is good. Large pox lesions involving the eyelids or diphtheritic oropharyngeal lesions interfere with vision and feeding and leave permanent scars. Scabs around a digit can lead to constriction injuries and loss of digits. Scabs on eyelids can cause keratitis and corneal ulceration.

iv. There are no commercially available flamingo pox vaccines. Mosquito control should include netting around the area where the birds are housed. Clinical cases should be isolated.

2 i. A coccidial oocyst (Eimeria spp.)

ii. Coccidia are commonly found in the intestine of red squirrels and are usually non-pathogenic; however, they can cause disease in stressed or immunosuppressed animals.

iii. Poor husbandry and management in captivity could be contributing to the diarrhoea. Red squirrels are nervous animals prone to stress in captivity, especially if being regularly handled. Stress should be reduced by keeping human contact to a minimum and keeping the squirrel in a warm quiet secluded environment. A nest box should be provided to make it feel more secure. Ideally, only one person should be responsible for feeding the squirrel and it should be handled confidently and gently. If kept with or near other squirrels, then competition, dominance or aggression might be causing stress. Strict hygiene is essential, especially in the areas where food is available. The milk replacer and any supplementary food should be fresh and suitable for red squirrels, and any changes to the diet gradually introduced.

3, 4: Questions

3 A harbour seal was admitted into rehabilitation as an abandoned dependent pup. Rehabilitation proceeded uneventfully for about three weeks, during which time the seal was fed on a liquid diet by gavage tube. The seal then started the weaning process, involving the introduction of assist-fed whole fish. Immediately on the introduction of whole fish, the seal showed intermittent distress on assisted feeding. Some fish were regurgitated immediately after feeding, others vomited within 30 minutes. Occasionally, feeding would progress without incident or vomiting.

Clinical examination revealed no abnormality and the animal was within normal weight range for the stage of rehabilitation. All standard blood parameters were normal. Plain radiographs of the chest and abdomen were unremarkable. 150 ml of barium contrast medium was delivered into the caudal oesophagus via gavage tube and a radiograph (3a) taken within five minutes.

i. What can you see on the radiograph?

ii. What is your diagnosis?

iii. When considering possible treatment options, what must be taken into consideration?

iv. Why are plain radiographs in seals often unrevealing?

4 You are presented with a young adult mute swan found this morning by the side of a road. The weather is wet and windy. On examination the swan has a slightly wide-based gait, is moderately underweight and has scuffed plantar feet and hocks, a wound on the skin over the keel bone and some bruising to the upper bill. The appearance of the wound, several days after débriding, is shown (4).

i. What are the possible differential diagnoses for this individual?

ii. What diagnostic tests might you perform?

iii. How would you treat such a wound in this species?

3, 4: Answers

3 i. A diaphragmatic hernia of the cardiac area of the stomach. A dilated caudal oesophagus, lightly outlined by barium and filled with air, is also visible.

ii. Diaphragmatic hernia and megaloesophagus (confirmed on necropsy, 3b).

iii. The diaphragmatic hernia might be operable and the megaloesophagus may respond to conservative treatment, although the prognosis for recovery would be guarded. However, in an animal intended for return to the wild, there are three major considerations:

• Possible interference with the diaphragmatic sphincter, which controls the flow of deoxygenated blood from the hepatic vein back to the heart during prolonged breath holding (part of the ‘dive reflex’) by surgical correction of the hernia could have severe repercussions for the seal;

• Significant risk of breakdown of a surgical repair during deep diving due to increased pressure on organs;

• This is a congenital and possibly hereditary condition. Should the seal survive and breed, it could propagate the condition in the wild population.

iv. Because of the lack of intra-abdominal fat. Although the percentage of fat to body mass in seals is similar to land mammals, the fat is concentrated in the blubber layer for insulation.

4 i. This has been caused either by a single traumatic event or because of a period of time spent in ventral recumbency on hard surfacing. The history is strongly suggestive of impact trauma (swans may land on wet roads, mistaking them for water) given the typical foot lesions.

ii. Swans suffering from lead poisoning are more likely to fly into power cables and other objects. It would therefore be advisable to screen for lead poisoning by gizzard radiography and blood lead analysis. Survey radiographs, especially of the pelvis, would be advised given the gait abnormality.

iii. The wound appears relatively superficial and to be healing well after débridement. Protective dressings, adherent to the skin or sutured into place, encourage granulation and offer physical protection while helping to keep the wound clean. More chronic or deeper wounds are challenging to treat. They may require repeated débridement, possibly even including bone. Avian skin is thin and inelastic; this area continues to be traumatized by contact with substrate, and the keel bone itself applies further localized pressure to the healing area. Thick bedding, protective dressings, systemic antibiosis and analgesia are all helpful. Swans rarely self-mutilate. The prognosis is guarded.

5, 6: Questions

5 This buzzard (5a) was brought in to the veterinary clinic by a member of the public. It was lethargic and anorexic and died shortly after examination.

i. Describe the lesions shown.

ii. What is the cause of this problem, and what treatment should be instituted?

6 A dead wild hare was submitted by a gamekeeper (6a). It was in an emaciated, dehydrated state with no evidence of diarrhoea. Fur around the mouth was darkened and matted and green food protruded, but there was no lip ulceration (6b). Palpation of the abdomen revealed very firm abdominal contents that subsequently proved to be due to the dehydration of the large bowel contents, which moulded to the folds in the wall. In addition, the stomach was distended and there were minimal internal body fat reserves. The lower lobes of the lungs were congested and firm due to inhalation pneumonia.

i. What condition is suggested by these external features?

ii. How would you investigate it further?

iii. Is this a common condition?

iv. Has it been seen in rabbits?

v. What is the cause of the condition?

5, 6: Answers

5 i. There...

Table of contents

• Cover Page
• Self-Assessment Colour Review Wildlife Medicine & Rehabilitation
• Copyright Page
• Preface
• Acknowledgements
• Picture acknowledgements
• Contributors
• Classification of cases
• Self-Assessment Colour Review Wildlife Medicine & Rehabilitation
• Appendix: Common and Latin names
• Index