BCSE Exotic, Avian, and Zoo Animal Medicine

Question 1

A psittacine bird presents with regurgitation, crop stasis, and neurological signs including ataxia and head tremors. Necropsy reveals proventricular and ventricular dilatation. The most likely diagnosis is:

Accepted Answer

Proventricular Dilatation Disease (PDD) caused by Avian Bornavirus

Answer

Proventricular Dilatation Disease (PDD) is caused by Avian Bornavirus (ABV). It is characterized by lymphoplasmacytic ganglioneuritis affecting the enteric nervous system, leading to proventricular/ventricular dilatation, GI dysmotility, and CNS signs. Fluoroscopy or contrast radiography demonstrating a dilated proventriculus and crop biopsy for lymphocytic infiltration support the diagnosis. It is common in macaws, cockatoos, and other psittacines.

Question 2

Rabbits are obligate nasal breathers and are prone to respiratory disease. The most common bacterial cause of upper respiratory tract disease ('snuffles') in rabbits is:

Accepted Answer

Pasteurella multocida

Answer

Pasteurella multocida is the primary pathogen responsible for 'snuffles' in domestic rabbits, causing mucopurulent nasal discharge, dacryocystitis, otitis media/interna, and pneumonia. It is endemic in many rabbit colonies. Bordetella can act as a secondary pathogen or potentiate Pasteurella infection, but is not the primary cause. Mycoplasma pulmonis is the major pathogen in rats and mice, not rabbits.

Question 3

Metabolic bone disease (nutritional secondary hyperparathyroidism) in captive reptiles is most commonly caused by:

Accepted Answer

Inadequate UVB light exposure and/or calcium:phosphorus imbalance leading to hypocalcemia

Answer

Reptiles require UVB radiation (290–320 nm) to synthesize vitamin D3 (cholecalciferol) in the skin, which is essential for intestinal calcium absorption. Without adequate UVB or dietary vitamin D3, secondary hyperparathyroidism develops as PTH mobilizes calcium from bone, causing pathological fractures, soft bones, and deformities. A poor Ca:P ratio (low calcium, high phosphorus) exacerbates the condition. This is extremely common in herbivorous lizards like green iguanas.

Question 4

Which analgesic opioid is commonly used in avian patients and has demonstrated efficacy in pain control in parrots based on pharmacokinetic studies?

Accepted Answer

Butorphanol

Answer

Butorphanol is the most commonly used and best-studied opioid analgesic in psittacine birds. Parrots have a higher density of kappa-opioid receptors than mu-opioid receptors compared to mammals, making kappa agonists like butorphanol particularly effective. Buprenorphine has limited efficacy in birds. Morphine has poor efficacy and can cause excitation. Transdermal fentanyl patches are unreliable in birds due to differences in skin structure and absorption.

Question 5

A ferret presents with episodic weakness, hypersalivation, pawing at the mouth, and blood glucose of 45 mg/dL. The most likely diagnosis is:

Accepted Answer

Insulinoma (pancreatic beta-cell tumor)

Answer

Insulinoma is the most common pancreatic neoplasm in ferrets, typically occurring in middle-aged to older animals. Excessive insulin secretion causes profound hypoglycemia, leading to weakness, salivation, pawing at the mouth (nausea), and seizures in severe cases. Diagnosis is supported by hypoglycemia with inappropriately elevated serum insulin. Adrenal disease is also common in ferrets but causes alopecia and sexual signs, not hypoglycemia.

BCSE - Basic and Clinical Sciences Examination Practice Test

BCSE - Basic and Clinical Sciences Examination Practice Test

BCSE Exotic, Avian, and Zoo Animal Medicine