Retinal Astrocytic Hamartomas: Unexpected Findings in a Giant Panda

A retrospective study on the prevalence of main clinical findings in brown bears (Ursus arctos) rescued from substandard husbandry conditions

Brown bears (Ursus arctos) are kept under varied captive conditions, some of which may greatly compromise their welfare. FOUR PAWS is an NGO that rescues some of these bears kept in substandard conditions and houses them in species-appropriate sanctuaries, where preventive and reactive veterinary care is provided. This retrospective study aims to provide an overview of pathologies and clinical abnormalities reported in veterinary records and their prevalence according to body system affected and pre-rescue bear origin. Origin was categorised as subzoo (bears coming from substandard zoos), dancing (used to "dance" upon a music cue), restaurant (used to attract clients), private keeping (used for various purposes, such as photo props), circus (used for shows), and bear-baiting (exploited for hunting dog training in baiting stations). Clinical findings were extracted from reports of veterinary examinations done from 2006 to 2021, during rescue, routinely, in response to clinical signs, and/or post-mortem. Their prevalence was calculated according to the body system affected and neoplasia (specific group independent from the organ) over the findings' total number. Prevalence was also calculated according to pre-rescue origin (general and relative values in proportion to the number of reports per origin). Results refer to 302 veterinary reports of 114 bears examined, rescued from 1998 to 2021, with the age at rescue varying from a few months to 30 years (median 13 years). The total number of clinical findings was 1,003, and the systems with more findings were oral cavity (56.0%), abdominal cavity and digestive system (7.9%), integumentary (7.9%), ocular systems (7.7%), and musculoskeletal (7.6%). Findings involving other body systems and neoplasia were less prevalent (≤2.8%). Results showed a higher prevalence of some clinical findings for bears rescued from certain origins compared to others. Straightforward associations between pre-rescue origin and clinical findings were not feasible due to unknown anamnesis and details on pre-rescue conditions, and because some housing and management characteristics might be transversal to origins. Results suggest that bears rescued from certain origins were prone to specific clinical findings, supporting the need for the creation of ad hoc preventive veterinary and husbandry management plans after rescue, thus contributing to the improvement of captive bear welfare.

Morphology and Histology of the Orbital Region and Eye of the Asiatic Black Bear (Ursus thibetanus)—Similarities and Differences within the Caniformia Suborder

In this study, we present first data concerning the morphological observations of the orbital region, eye tunics, upper and lower eyelids, superficial gland of the third eyelid with the third eyelid, and lacrimal gland in captive adult male Asiatic black bear. The following research methods were used in the work: the eyeball morphometry, the orbital region description, macroscopic description, morphometric and histological analysis of the eye tunics and selected the accessory organs of the eye (Fontana–Masson, hematoxylin & eosin (H&E), Methyl-green-pyronin Y (MGP Y), Movat pentachrome, and picro-Mallory trichrome) as well as histochemical examination (PAS, AB pH 1.0, AB pH 2.5, AB pH 2.5/PAS and HDI). The eyeball of the Asiatic black bear was a spherical shape, while the periorbita was funnel/conical-shaped and the eye socket was of the open type. The cornea was absent of the Bowman’s membrane similar to all domestic dogs and some wild dogs. There were palisades of Vogt in the corneal limbus epithelium similar to the Canidae. Degenerative choroidal tapetum lucidum similar to ranch mink (Mustelidae) has been found. The pupil was big and round in shape. The ciliary muscle, dilatator and sphincter muscle were well developed, similar to the pinnipeds. The lens was biconvex round, similar to the Canidae. The retina was composed similarly to the diurnal terrestrial carnivores. In both eyelids were observed very well-developed tarsal glands, ciliary glands and sebaceous glands. The orbital zone in the eyelids was characterized by lymphoid follicles, diffuse lymphocytes and specialized high endothelial venules. In the anterior palpebral margin of the upper eyelid, soft and short eyelashes were observed, while in the lower eyelids they were absent. The third eyelid was T-shaped and composed of the hyaline tissue, and it contained CALT, similar to that in Canidae. The superficial gland of the third eyelid was a multilobar alveolar branched complex with seromucous nature, while the lacrimal gland was also a multilobar acinar branched complex gland, but producing a mucous–serous secretion. The results of our research indicate that the features of the anatomy of the eye and orbital region in Asiatic black bear are also typical of the Ursidae family. Moreover, a detailed analysis of the morphological eye region may be useful in comparative studies and veterinary diagnostics in this bear species.

SURVEY OF CLINICAL OPHTHALMIC DISEASE IN THE GIANT PANDA (AILUROPODA MELANOLEUCA) AMONG NORTH AMERICAN ZOOLOGICAL INSTITUTIONS

This study surveyed six North American zoologic institutions to collect retrospective information on the incidence of ocular disease in the giant panda. Reported information included sex and age at presentation, as well as diagnosis, treatment, duration, and clinical outcome for each episode of ocular disease. Among the 42 animals included in the survey, 10 (23.8%) had clinical ocular abnormalities reported. Multiple disease episodes were reported in four animals, with 20 clinical episodes, and one additional animal who presented with corneal scarring from historic keratitis. Age at presentation varied from 0.4 to 26 yr (mean, 11.8 yr; median, 10.4 yr). Corneal abnormalities (including corneal opacity or haze, keratitis, corneal ulcers, and bullous keratopathy) were the most common pathologies reported, followed by conjunctivitis and/or ocular discharge. Additional reported abnormalities included limbal squamous cell carcinoma and lipid degeneration. Six cases resolved without intervention. Treatment protocols included topical and/or systemic medication with or without surgical intervention, which commonly resulted in resolution with or without persistent corneal scar. The prevalence of ocular disease identified in the giant panda in this study is higher than previous publications surveying ocular disease in the family Ursidae, indicating that this is an important source of morbidity in this species.

Solitary Biliary Hamartoma with Cholelithiasis in a Domestic Rabbit (Oryctolagus cuniculus)

Hamartomas of the liver and biliary system are extremely rare entities in both animals and humans. Biliary hamartomas in humans are usually multiple and constitute the von Meyenburg complexes. This report describes the presence of a large solitary mass arising from the edge of the right medial liver lobe of a domestic rabbit. Histologically, the mass was composed of an extensive network of large varying sized cystic structures lined by simple cuboidal to columnar epithelium within an abundant fibrous stroma. Within many of the cyst lumina were varying sized, pale white to greenish hard concretions identified as choleliths and were analyzed and found to be composed of calcium carbonate. This is the first known report of biliary hamartoma with cholelithiasis in rabbits.

Medical and surgical management of severe inflammation of the nictitating membrane in a Giant Panda (Ailuropoda melanoleuca)

A 10-year-old male giant panda (Ailuropoda melanoleuca) presented for severe, acute swelling and protrusion of the right nictitating membrane, unresponsive to topical therapy. Excisional biopsy of the nictitating membrane and its associated lacrimal gland was elected due to necrosis and friability of the tissue. Histopathology revealed suppurative, necrotizing conjunctivitis and dacryoadenitis. Culture grew Stenotrophomonas maltophila and Enterococcus spp with extensive antibiotic resistance. Treatment with topical and systemic antibiotics based on sensitivity results was initiated. All treatments were well tolerated. Healing was uncomplicated with no recurrence of the lesion and no clinical evidence of keratoconjunctivitis sicca. Ophthalmic exams and Schirmer tear tests performed opportunistically during postoperative anesthetic procedures were unremarkable, confirming that excision of the nictitating membrane had not caused clinically significant detrimental effects. The etiology of this lesion remains undetermined, but trauma is suspected. To the authors' knowledge, this is the first report of nictitating membrane pathology and excision in the giant panda.