TRANSMISSION OF A CHRONIC LYMPHOPROLIFERATIVE SYNDROME IN FERRETS

BACKGROUND: Lymphomas and leukemias are caused by transmissible viruse s in a wide variety of species, including humans, cattle, and cats. Fe atures of lymphoma in ferrets suggest that it, too, may have an infect ious etiology. No agent has been identified. EXPERIMENTAL DESIGN: Cell s or cell-free inocula from a ferret with spontaneous malignant lympho ma were administered i.p. to six recipient ferrets. Two ferrets receiv ed fresh cells, two received frozen cells, and two received cell-free culture supernatant. The recipients were monitored routinely clinicall y and hematologically, and lymphoma was confirmed histologically. The lymphomas were characterized using cytology, cytochemistry, immunophen otyping, and histology. Cultivated cells from the donor and recipients were examined using reverse transcriptase assay, microscopy, and elec tron microscopy. RESULTS: All of the six recipient ferrets developed m ild sustained lymphocytosis within 6 weeks of the inoculation. Two of six were euthanized 14 to 18 months after inoculation, Lymphoma was la ter diagnosed in three of the four remaining ferrets at 24 to 36 month s after inoculation. All developed a chronic indolent syndrome featuri ng profound splenomegaly, lymphocytosis with atypia, and histologicall y polymorphous lymphoma. Two of the three who developed lymphoma had r eceived fresh donor lymphoma cells, and the third had received superna tant from donor cell cultures with elevated reverse transcriptase acti vity. Cultivated cells from the affected ferrets demonstrated reverse transcriptase activity and retrovirus-like particles. CONCLUSIONS: Thi s study demonstrates horizontal transmission of malignant lymphoma in ferrets using cell or cell-free inocula. Clinical and pathologic featu res of this syndrome in ferrets resembled virally induced lymphomas in other species.