Transmission of Virus From Field Cases of Avian Lymphomatosis. I. Isolation of Virus in Line 151 Chickens2

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Abstract
Tumors were collected from chickens with visceral lymphomatosis in 19 farm flocks. Material was also collected from chickens with neural lymphomatosis of an experimental flock and ocular lymphomatosis of 2 other flocks and from a chicken with nephroblastoma of another flock. Day-old line 151 chicks were inoculated intra-abdominally with tumor extracts, oral washings, or plasma, and held for an experimental period of 245 days. Cell-free inoculums from 10 of the 19 flocks induced a total neoplastic mortality of more than 50 percent. An extract of the nephroblastoma also caused a high incidence of neoplasms. Material from neural lymphomatosis and ocular lymphomatosis induced moderate neoplastic mortality. Most of the mortality was from visceral lymphomatosis and to a lesser extent from erythroblastosis. Most sources also caused osteopetrosis and a few fibrosarcomas and endotheliomas. Sporadic cases of neural lymphomatosis but none of nephroblastoma or myeloblastosis were observed. There appeared to be no correlation between oncogenic activity of the inoculums and the breed or the age of the donor birds or size and type of flock. The microscopic appearance of lymphoid tumors was of no value in the estimation of the potency of extracts made from them. Fairly uniform quantitative and qualitative responses were induced by the more potent isolates obtained from cases of visceral lymphomatosis from flocks with a high incidence of this disease. The responses were similar to those induced by a low dose of the RPL12 strain of avian tumor virus.