Spinal disease of captive snakes is described in several zoological publications. A summary of these along with a clinicopathologic observational study described a spectrum of vertebral lesions directly or presumably attributable to Salmonella osteomyelitis.1 In that report and others, a subset of snakes had lesions in the absence of inflammation or apparent infection, likened to human Paget’s disease. We report an ongoing spinal osteoarthropathy (SO) of snakes, most of which are not referable to a demonstrable infectious/inflammatory process. San Diego Zoo snake mortalities from 2000–2017 were evaluated to identify cases defined by histologic determination of abnormal osteochondral proliferation with or without fibroplasia, necrosis, and inflammation, primarily affecting the vertebrae and associated articulations. Analyses included descriptive temporal trends in mortality, comparison of prevalence by taxonomic family, and univariate odds ratios to identify high-risk groups. In total, 93 snakes out of 616 mortalities were diagnosed with SO. From 2000–2014, 8% of snake mortalities were associated with SO, increasing to 35%, 44%, and 52% in years 2015, 2016, and 2017, respectively. The highest SO prevalence occurred in Pythonidae (25%; 18/72) and the lowest in Homalopsidae (0%; 0/34) and significant differences in SO prevalence existed between some taxonomic groups. Bivariate analyses showed no significant difference in risk according to sex and significantly higher risk for subadults (OR:23.2; p<0.001) and adults (OR:10.3; p<0.001) compared to neonates and juveniles. Pursuit of a definitive etiology includes rigorous clinical data analyses, viral metagenomics, hepatic mineral levels, comparison of rodent versus non-rodent diets, and whole-prey nutrient analyses.
The authors thank the dedicated reptile keepers, animal care managers, veterinary technicians, and pathology research associates for their critical involvement in clinical management and pathologic evaluation of the population in this investigation.
1. Isaza R, Garner M, Jacobson E. Proliferative osteoarthritis and osteoarthrosis in 15 snakes. J Zoo Wildl Med. 2000;31(1):20–27.