Case Report: Lymphosarcoma in Adult African Green Monkeys (Chlorocebus Aethiops)

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 rhodesiense as a model of human trypanosomiasis  and subsequently treated with a proprietary trypanocidal drug and observed for any aftereffects.  Th e other monkey was used to test for the safety of another trypanocidal drug.During the monitoring  period, terminated 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 animals 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 animals the neoplastic infiltrates  were dominated by large lymphocytes with anisokaryosis 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 1 (STLV-1).