Pathology and Epidemiology of Oxalate Nephrosis in Cheetahs

Abstract

To investigate cases of acute oxalate nephrosis without evidence of ethylene glycol exposure, archived data and tissues from cheetahs ( Acinonyx jubatus) from North America ( n = 297), southern Africa ( n = 257), and France ( n = 40) were evaluated. Renal and gastrointestinal tract lesions were characterized in a subset of animals with ( n = 100) and without ( n = 165) oxalate crystals at death. Crystals were confirmed as calcium oxalate by Raman spectroscopy in 45 of 47 cheetahs tested. Crystals were present in cheetahs from 3.7 months to 15.9 years old. Cheetahs younger than 1.5 years were less likely to have oxalates than older cheetahs ( P = .034), but young cheetahs with oxalates had more oxalate crystals than older cheetahs ( P < .001). Cheetahs with oxalate crystals were more likely to have renal amyloidosis, interstitial nephritis, or colitis and less likely to have glomerular loop thickening or gastritis than those without oxalates. Crystal number was positively associated with renal tubular necrosis ( P ≤ .001), regeneration ( P = .015), and casts ( P ≤ .001) but inversely associated with glomerulosclerosis, renal amyloidosis, and interstitial nephritis. Crystal number was unrelated to the presence or absence of colitis and was lower in southern African than American and European animals ( P = .01). This study found no evidence that coexisting chronic renal disease (amyloidosis, interstitial nephritis, or glomerulosclerosis), veno-occlusive disease, gastritis, or enterocolitis contributed significantly to oxalate nephrosis. Oxalate-related renal disease should be considered as a potential cause of acute renal failure, especially in young captive cheetahs. The role of location, diet, stress, and genetic predisposition in the pathogenesis of oxalate nephrosis in cheetahs warrants further study.

A new perspective on the pathogenesis of chronic renal disease in captive cheetahs (Acinonyx jubatus)

“…Chronic renal disease was not assigned as the cause of death in cheetahs which had moderate or severe lesions in other organs. Data relating to oxalate nephrosis were excluded as previous work had demonstrated no connection between this condition and other renal parameters [ 38 ].…”

“…Diet in captivity also affects the incidence and prevalence of gastrointestinal tract disease in captive cheetahs[ 36 , 37 ]. Cheetahs are susceptible to oxalate nephrosis which is not primarily caused by ethylene glycol exposure and is not linked to concurrent glomerulosclerosis or medullary amyloidosis [ 38 ].…”

Felidae

“…Since the mid 1970's, sporadic cases of oxalate nephrosis have been reported in captive cougars, jaguars, leopards, and most commonly, cheetahs (Mitchell et al, 2017). Affected cats are found dead or present in acute renal failure with severe azotemia, and poly-to anuria.…”

Observational Study Design in Veterinary Pathology, Part 2: Methodology

“…For example, X-ray fluorescence microscopy and Raman spectroscopy were used to characterize metal alloy and oxalate crystals within tissues, respectively. 11,33 Bone metastases were verified by both histopathology and computed tomography. 7 Just as you wouldn't invest retirement savings in a single stock, we shouldn't base our understanding of a disease on a single methodology.…”