Case Report: Lymphosarcoma in Adult African Green Monkeys (Chlorocebus

Abstract

The clinical observations and pathological manifestations of lymphosarcoma in two African green monkeys are described. Monkeys had been caught from the wild. Prior to the development of neoplasms one monkey had been experimentally infected with trypanosoma brucei rhodeslense as a model of human trypanosomiasis and subsequently treated with a proprietary trypanocidal drug and observed for any aftereffects. The other monkey was used to test for the safety of another trypanocidal drug. During the monitoring period term mated by euthanasia. Monkey became dull, unable to perch, and hunched. In the same animal the facial skin became hypersensitive and nodular skin lesions developed in the other animal used in safety study skin lesions. Weight loss and swollen eyelids were observed prior to euthanasia. During the terminal stages of the experimental protocol, the superficial lymph nodes of both al1lmals became swollen and the white blood cell count increased. Lesions disclosed during necropsy and subsequent histopathology revealed classical signs of nodular multicentric lymphosarcoma. In both al1lmals the neoplastic infiltrates were dominated by large lymphocytes with al1lsokaryosls and megakaryosis. In several organs (lungs. liver and kidneys) of one of the animals, the neoplastic infiltrates were accompanied by compression and degeneration of bordering tissues. The cause of the neoplasms remains unknown, but stress-induced Immunosuppression associated with captivity. To a lesser extent and more importantly the induction and treatment of experimental trypanosomiasis may, have triggered the onset of neoplastic proliferation, which IS frequently associated with simian T-cell leukemia virus I (STLV-l).