Causes of morbidity in captive African lions (Panthera leo) in North America, 2001-2016

The lion (Panthera leo) is an iconic resident of zoos and wild animal parks throughout the world. Regular assessment of the morbidity of captive lions is necessary to address wellness concerns and improve the healthcare and management of this vulnerable species. In an effort to understand disease morbidity broadly and guide future inquiries into captive lion health, we distributed a questionnaire that emphasized diseases of organ systems rather than individual diagnoses. We sent the questionnaire to 108 American Zoo and Aquarium Association (AZA) institutions housing lions between 2001 and 2016. Fifty-six facilities responded of which 32 responses had usable data for 111 lions. Responses were compiled and analyzed with respect to age, class, and sex. Neoplasia, renal disease, and dental disease were the most common causes of morbidity in these captive lions. Older animals generally experienced a higher prevalence of multiple types of disease. Three cases of hypertrophic cardiomyopathies (HCM) were reported in nearly 40% (3/8) of cardiovascular diseases and 3% (3/111) of disease cases overall, which is the first report of HCM in lions, to the authors' knowledge. There is a relative paucity of literature on lion and large felid cardiovascular conditions, which suggests that this may be an understudied area of lion health. This broad assessment of morbidities present in captive lion populations aimed to identify key areas for further research and screenings. Management priorities of captive lions should include prevention strategies for dental disease and trauma, frequent screening for renal disease and neoplasia, and further research into cardiovascular health.