ABSTRACT
Avian leukosis viruses occur naturally only in domestic fowl and pheasants although many species of fowl are susceptible to experimental infection. Despite the potential of high rates of infection few birds actually acquire a viral-induced neoplastic disease which may terminate as a hemopoietic neoplasm such as erythroleukemia, lymphoid leukosis and myeloblastosis/monocytic leukosis or non-hematologic disease as a nephroblastoma, chondroma, fibrosarcoma, or other tumors. Erythroid leukosis/leukemia, also commonly termed “erythroblastosis”, is an uncommon, sporadic disease affecting mainly adult chickens. Influence of virus dose on mortality from erythroblastosis and visceral lymphomatosis. Cytologic examination of the marrow in early cases of viral induced erythroleukemia reveals that the blood sinusoids become filled with rapidly proliferating erythroblasts that fail to mature. The erythroleukemic process results in an erythroblastic engorgement of the sinuses. Viral particles budding from the cell membrane are seen in erythroblasts circulating in the blood and in cell culture.
