title: Occurrence, transmission and oncogenic spectrum of the avian leukosis viruses.
mesh_terms: D000367:Age Factors; D001355:Alpharetrovirus / Q000472:pathogenicity; D000818:Animals; D001353:Avian Leukosis / Q000453:epidemiology / Q000635:transmission; D001715:Bird Diseases / Q000382:microbiology; D002645:Chickens; D003168:Complement Fixation Tests; D012509:Sarcoma / Q000382:microbiology