Malignant Plasma Cell Neoplasia in Ferrets: A Review of 6 Cases

Myocardial plasma cell tumor with intratumoral amyloidosis in a dog

A 12-year-old mixed breed dog was evaluated for marked hypercalcemia that was identified during assessment for acute polydipsia and polyuria. Physical examination identified a new grade II/VI left apical systolic murmur. A mass involving the left ventricular posterior wall and left atrium was identified by echocardiography, suggesting neoplastic invasion into the myocardium. The patient was euthanized, and post-mortem cardiac evaluation identified an intramyocardial amyloid-producing plasma cell tumor. Multiple myeloma was suspected but could not be confirmed due to the limited post-mortem evaluation. This case is the first report of myocardial amyloidosis in a dog with a myeloma-related disorder (MRD). Dogs with MRD and myocardial involvement may not exhibit clinical signs that localize to the cardiovascular system; therefore, echocardiography should be considered during the staging process.

Neoplasia in Ferrets

Neoplasia is a common cause of disease in domestic ferrets worldwide. The most common neoplasms are islet cell tumors (insulinoma), adrenocortical neoplasms, and lymphoma. The definitive etiology has yet to be defined, but husbandry, genetic predisposition and infectious agents are postulated causes. Definitive diagnosis requires sampling and microscopic analysis of the neoplasm, but initial testing including blood, urine and diagnostic imaging can aid the diagnostic process. Based on the type of tumor and its location, therapeutic options include surgery, chemotherapy and radiation therapy. Numerous chemotherapeutic protocols and drugs have been published for the use in ferrets and a ferret specific formula for calculating body surface area has been established. In addition to the more commonly affected endocrine and hemolymphatic systems, ferrets can also develop tumors in the skin and subcutis, gastrointestinal and reproductive tracts, musculoskeletal, nervous, urinary, respiratory and vascular systems.

Founder events, isolation, and inbreeding: Intercontinental genetic structure of the domestic ferret

Domestication and breeding for human-desired morphological traits can reduce population genetic diversity via founder events and artificial selection, resulting in inbreeding depression and genetic disorders. The ferret (Mustela putorius furo) was domesticated from European polecats (M. putorius), transported to multiple continents, and has been artificially selected for several traits. The ferret is now a common pet, a laboratory model organism, and feral ferrets can impact native biodiversity. We hypothesized global ferret trade resulted in distinct international genetic clusters and that ferrets transported to other continents would have lower genetic diversity than ferrets from Europe because of extreme founder events and no hybridization with wild polecats or genetically diverse ferrets. To assess these hypotheses, we genotyped 765 ferrets at 31 microsatellites from 11 countries among the continents of North America, Europe, and Australia and estimated population structure and genetic diversity. Fifteen M. putorius were genotyped for comparison. Our study indicated ferrets exhibit geographically distinct clusters and highlights the low genetic variation in certain countries. Australian and North American clusters have the lowest genetic diversities and highest inbreeding metrics whereas the United Kingdom (UK) cluster exhibited intermediate genetic diversity. Non-UK European ferrets had high genetic diversity, possibly a result of introgression with wild polecats. Notably, Hungarian ferrets had the highest genetic diversity and Hungary is the only country sampled with two wild polecat species. Our research has broad social, economic, and biomedical importance. Ferret owners and veterinarians should be made aware of potential inbreeding depression. Breeders in North America and Australia would benefit by incorporating genetically diverse ferrets from mainland Europe. Laboratories using ferrets as biomedical organisms should consider diversifying their genetic stock and incorporating genetic information into bioassays. These results also have forensic applications for conserving the genetics of wild polecat species and for identifying and managing sources of feral ferrets causing ecosystem damage.