This retrospective study identified and characterized brain lesions in captive non-domestic felids from a large cat sanctuary, submitted to the University of Tennessee College of Veterinary Medicine for postmortem analysis. Necropsy reports from January 2002 through December 2018 were examined, and gross images and microscopic slides were reviewed from individual cats where available. In total, 255 cats met the inclusion criteria (brain examined grossly and/or microscopically and age >30 days), of which 49 cats (19%) were determined to have brain lesions. Eleven different felid species, as well as one captive-bred hybrid (liger) were included in the study, with tigers (Panthera tigris) (55%) and lions (Panthera leo) (18%) the most common species. Lesions were grouped into six etiologic categories: neoplastic (31%), vascular (23%), inflammatory (22%), congenital (10%), idiopathic (8%), and metabolic (6%). Not included in the brain lesions categorized above were previously undescribed amphophilic globules in the cerebral cortex of many cats with and without other brain lesions. This included 95% of lion and 93% of tiger brains where the cerebral cortex was available for examination. These globules were not associated with clinical disease, and therefore their significance should be interpreted with caution. Overall, brain disease was identified as the primary cause of mortality in 19 of 255 animals (7%), and all 19 had brain lesions. The histopathologic and gross brain changes documented in this study provide insight into specific diseases and pathologic processes that affect the brains of captive large cat populations.
The authors thank Ms. Mary Lynn Haven and Ms. Debbie Chaffins at Tiger Haven, as well as Heather Kloft, Mary Catherine Johnson, and the faculty, residents, interns, technicians and lab technicians of the necropsy and zoological medicine services at the University of Tennessee, for their assistance in data acquisition.