Abstract: 【Objective】 The study was aimed to understand the infection and gene molecular characteristics of E-avian leukosis in a chicken flock in a city of Xinjiang.【Method】 Laboratory diagnosis of suspected avian leukosis cases was conducted through pathological dissection,histopathological observation,PCR detection,clone vector linkage,etc,and DNAStar software was used to perform env gene nucleotide sequence similarity alignment,phylogenetic tree construction,and mutation site analysis between the isolated strain and the reference strains.【Result】 The liver,heart,spleen,kidney,lung and other organs of the affected chickens were enlarged with white nodular foci of different sizes.Histopathological observation showed that the foci were uniformly sized adult lymphocytes with focal and diffuse distribution.The PCR amplification results of the Avian leukaemia virus (ALV) genome showed that a target band with a size of 302 bp was obtained,which was positive for ALV.Typing identification was performed on positive samples,which showed ALV-E specific bands with a size of 1 074 bp,named AKS2101 and AKS2102,respectively.The sequence analysis results showed that the sequence similarity between the isolated strains and the subgroup E strains was 91.6% to 98.6%.The phylogenetic tree showed that the obtained sequences were in the same branch as the reference strain of ALV-E subgroup,and was in a different evolutionary branch from the reference strains of subgroups A,B,C,D,J and K,further indicating the presence of ALV-E infection in the chicken population.Genetic variation analysis showed 24 nucleotide variations and 17 amino acid site variations in the isolated strain,with variable sites located in the highly variable region of the sequence.【Conclusion】 ALV-E infection existed in chickens in a city of Xinjiang,and this experiment provided basic data to clarify the prevalence of avian leukosis in this area.

Key words: Avian leukaemia virus (ALV); subgroup E; pathology; molecular biology; gene sequence; diagnosis