Two cases of sick chickens, which were suspect to be infected with J-Subtype Avian leukosis virus(ALV-J), were diagnosed by clinical observation and pathological anatomy. The results indicated that swollen and tumor nodules were observed in liver, heart, spleen and lung. Based on the published gp85 sequence of ALV-J, a pair of PCR primers was designed to amplify the nucleic acids of ALV-J. The result found that a 924 bp specific band that agrees with the expected size of ALV-J gp85 was amplified from two li...