Objective--To test the hypothesis that the predominant mineral type in naturally occurring ferret uroliths was sterile struvite and to determine if age, breed, gender, reproductive status, geographic location of ferrets, season of the year of uroliths submission, and anatomic location within the urinary tract were risk factors associated with ferret sterile struvite uroliths formation.
Design-- Case-control retrospective study
Animals--408 case ferrets from the Minnesota Urolith Center (MUC) and 6528 control ferrets from the Veterinary Medical Data Base (VMDB) 1981 through 2007.
Procedure-Historical information about age, gender, reproductive status, anatomic location within the urinary tract, and season of the year of urolith submission were obtained about each ferret. The association between these factors and outcome (sterile struvite urolith formation) was statistically assessed.
Results--Sterile struvite was the predominant mineral in ferret uroliths. Cystine comprised the next most common type of urolith, followed by calcium oxalate. Neutered male ferrets had increased risk of developing sterile struvite uroliths. A significant association was also found between the ages of 2 years and < 7 years and the detection of struvite uroliths. Also a significant association was found between advancing age and the detection of struvite uroliths. Ferret struvite uroliths were more likely to be retrieved from the lower urinary tract (bladder and urethra, n = 254) than from the upper the urinary tract (kidney and ureter, n = 4) (the location of 14 uroliths was not recorded).
Conclusion and Clinical Relevance-- Knowledge of predominant mineral type in uroliths along with insight into etiologic, demographic, and environmental risk and protective factors for urolithiasis may facilitate development of surveillance strategies that could result in earlier detection of uroliths in ferrets. Modification of risk factors including dietary risk factors may help to minimize urolith formation, dissolve existing uroliths and minimize urolith recurrence.
In context of sterile struvite urolithiasis, ferrets and domestic cats are remarkably similar. Both species are true carnivores. Both species form sterile struvite uroliths. In both species, infection-induced uroliths are uncommon. In both species, bacterial urinary tract infections are apparently uncommon. The advent of safe and effective diet therapy to induce dissolution of sterile struvite uroliths in cats, and the striking parallels between ferret and feline urolithiasis, prompts the question as to the safety and efficacy of diet-induced dissolution and prevention of sterile struvite urolith formation in ferrets. The primary goal of this study was to compare features of sterile struvite in cats with those in ferrets. Results of these comparisons may provide a logical evidence-based rationale for clinical trials to determine the safety and efficacy of diet-induced dissolution of sterile struvite uroliths in ferrets.
University of Minnesota M.S. thesis. August 2010. Major: Veterinary Medicine. Advisors: Carl Andrew Osborne and Jody Pierre Lulich. 1 computer file (PDF); xii, 70 pages, appendices A-D. Ill. (some col.)
Nwaokorie, Eugene Emeka E..
Epidemiology of struvite urolithiasis in ferrets..
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