Copper toxicosis in sibling ferrets.

Two sexually intact female silver-shaded domestic ferret siblings from different litters were examined because of CNS depression and lethargy. Ferret 1 was dehydrated and hypothermic, whereas ferret 2 was icteric and febrile and had serum bilirubin concentration > 12.0 mg/dl and BUN of 59 mg/dl. Despite supportive treatment, the ferrets died within days of evaluation. On necropsy, ferret 1 had chronic hepatopathy, with diffuse vacuolation of hepatocytes. In ferret 2, the liver had centrilobular degeneration and necrosis, and hemoglobinuric nephrosis was evident, with hemoglobin in the renal tubules. In both ferrets, Kupffer's cells and macrophages contained eosinophilic material in the cytoplasm. Special staining revealed copper pigment in hepatocytes and phagocytic cells in both livers. Analysis of liver specimens revealed 850 and 700 ppm of copper in ferrets 1 and 2, respectively. Copper values > 200 ppm in liver are considered evidence of toxicosis in most animal species. Copper toxicosis was diagnosed on the basis of the findings from histologic examination of the liver and high hepatic copper values. Lack of related illness in 11 other ferrets in the same environment and fed the same diet, plus sibling relationship and same phenotypic coat color in the affected ferrets, suggested that these ferrets had an inherited defect in their ability to metabolize normal amounts of ingested copper.