Biology and Diseases of the Ferret by Fox James G.; Marini Robert P.; & Robert P. Marini

Author:Fox, James G.; Marini, Robert P.; & Robert P. Marini
Language: eng
Format: epub
ISBN: 9780470960455
Publisher: John Wiley & Sons, Incorporated
Published: 2014-03-24T15:09:47+00:00

When examined by slit lamp biomicroscopy, 34 of 73 (47%) of ferrets, aged 11–12 months, had lens opacities [37]. Lesions in the lens ranged from fine, multifocal, punctate opacification to mature cataracts. Eighteen weeks after the initial examination, 36 of the remaining 45 animals from the initial survey had lenticular opacities. When examined at 17–18 months of age, the opacifications often extended throughout the posterior lens cortex, rather than being confined to the subcapsular area. In another ferret population of different genetic background, 3 of 47, 6-month-old juveniles were classified as normal, and 16 had some form of lens opacification. Thus, many ferrets have slowly progressive formation of cataracts. Lens opacification appeared to begin as white, multifocal, punctate opacities diffusely scattered in the posterior, and subsequently anterior, cortical/subcortical area [37]. The lesions present in the cortical and subcapsular area indicate that the cataract formation may be secondary to lens epithelial cell growth and maturation abnormalities. Cataracts affecting the nucleus of the lens in young animals usually reflect a prenatal insult in early lens development; others suggest that they are congenital in origin. Animals with luxation of normal or cataractous lenses have also been recorded as having retinal degeneration due to luxated cataracts [38,39].

Although genetics may well play a role in the high frequency of cataracts in this population, diet may also influence expression of this disease. High-fat diet and production of reactive oxygen radicals with inadequate antioxidants in the diet may have created lipid perioxidation cataracts. Dietary deficiency in vitamin E or relative excess of polyunsaturated fats have been described in ferrets, and dietary deficiency in vitamin E has been associated with cataracts in rats [40]. Cataracts due to arginine deficiency have also been recorded in dogs and wolves [41,42]. Interestingly, the group of ferrets with a high incidence of cataracts was fed a mink diet which may have had nutritional components insufficient for optimum lens development, growth, and maturation [37]. Diabetes mellitus has been infrequently diagnosed in ferrets [43,44]. Cataract formation can occur in diabetic animals; this has been reported in ferrets with the disease. Diseases causing secondary cataracts, in addition to diabetes mellitus, are retinal detachment, or degeneration, anterior uveitis, and lens luxation. The rate of cataract progression is dependent on the age of the ferret and the cause and location of the cataract [45].

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