Aortic Aneurysm, Dissection, and Rupture in Six Bile-Farmed Bears

Abstract

Across China and Southeast Asia, over 17,000 bears are currently farmed for bile, predominantly for traditional Chinese medicines. Bears on farms in China are cage confined and undergo repeated daily bile extraction facilitated by surgically implanted catheters or gallbladder fistulas. Numerous health problems have been reported in bile-farmed bears including peritonitis, abdominal hernias, and extraction site abscessation. Between 2009 and 2014, five Asiatic black bears ( Ursus thibetanus) and one Asiatic black/Eurasian brown bear ( Ursus arctos arctos) hybrid, rescued from the bear bile industry in China, died from ruptured and/or dissecting aortic aneurysm. Medical records were reviewed and two bears exhibited no clinical signs prior to death. In four bears, clinical findings varied and included increased stereotypic behavior prior to death, epistaxis, retinal lesions, dysphagia, weight loss, and acute onset of hyporexia. On postmortem examination, hemopericardium with dissection and/or rupture of the ascending aorta and left ventricular wall hypertrophy were present in all cases. No evidence of infectious disease, connective tissue disorders, or congenital cardiac disease was identified. Based on these observations screening thoracic radiography was performed on all bears at the rescue center and aortic dilation was identified in 73 of 134 (54.5%) bile-extracted bears. To the authors' knowledge, aortic aneurysm, rupture, and/or dissection have not been previously reported in any bear species and the high prevalence in this population of bears suggests an association with bile-farming practices. Future studies are needed to investigate the etiopathogenesis of this condition to aid in early diagnosis and improved management of bears being rescued from bile farms across Asia.

Metabolic derangements and reduced survival of bile-extracted Asiatic black bears (Ursus thibetanus)

“…Most commonly, BE, FNE, and ZOO bears were induced using a combination of zolazepam-tiletamine (Zoletil 100, Virbac, Bury St Edmonds, Suffolk IP30 9UP, England) and medetomidine (Domitor, 1 mg/ml, Zoetis, London EC4A 3AE, England) at dosages ranging from 1 to 3 mg/kg (Zoletil) combined with 0.04 to 0.1 mg/kg (Domitor) administered intramuscularly via pole syringe or blowpipe. BE and FNE bears were intubated and maintained on 1–3% isoflurane as described previously [9]. FR bears were captured and re-released using barrel traps that were baited with honey, anesthetized with zolazepam-tiletamine (Zoletil, Virbac, Carros, France) at an average dose of 7.3 mg/kg, administered via blowpipe as described previously (one FR bear was anesthetized using a combination of zolazepam-tiletamine (2.6 mg/kg) and medetomidine (0.03 mg/kg) as described above) [33].…”

“…Additional clinical findings include abnormal behaviors and severe stereotypy, fractured teeth, spondylosis and degenerative joint disease, and missing digits, paws, or limbs presumably from snare traps [6]. Leading causes of death in previously bile-farmed bears are hepatobiliary neoplasia, hindlimb paralysis and deteriorating mobility, and cardiovascular disease, including congestive heart failure and aortic aneurysm rupture/dissection [6, 9]. Bile farmed bears are thought to have a greater prevalence and severity of disease, including comorbidities, than expected for most captive bears, and the types of disease, such as ruptured aortic aneurysm, appear unusual for bear species in general [9, 10].…”

Modification of Domestic Animal Lameness Scales for Use in Asiatic Black Bears (Ursus thibetanus)

“…Before arriving at the rescue center, most of the resident bears had spent over a decade on bile farms in small cages, with very poor welfare and high levels of chronic stress [38]. Due to these conditions, many rescued bears suffer from long-term diseases, such as hypertension, heart disease, dental disease, liver/gall bladder diseases, and osteoarthritis (a progressively worsening inflammation of the joint caused by the deterioration of cartilage) [15,39,40]. Most of the lameness conditions observed in rescued bears are a result of osteoarthritis, which is diagnosed by physical examination and radiographs while chemically immobilized.…”

New insights into dietary management of polar bears (Ursus maritimus) and brown bears (U. arctos)

“…This link between high protein diets, or another nutrient closely associated with protein (e.g., phosphorus), and kidney disease has also been reported in many other animals, including humans (Bilsborough & Mann, 2006; Boswald et al, 2018; Laflamme et al, 2020; Rode et al, 2021; Wakefield et al, 2011). Renal disease often leads to high blood pressure (Acierno et al, 2018; Bando et al, 2018), which may account for the cardiovascular disease occurring in captive polar bears, particularly in those bears with concurrent kidney and cardiovascular disease (Table 1). While there is a high incidence of liver disease and cancer in captive polar bears, little is known about the potential role of high protein diets as a causal factor.…”