Purpose The aim of this study was to determine the detection rate of avian leukosis virus (ALV) markers, subgroup composition, and molecular characteristics in the core production areas of Wuding chickens.
Methods Paired cloacal swabs and blood samples were collected from 349 chickens across seven sampling sites. The ALV-p27 antigen in the swabs was detected using ELISA. Total RNA was extracted from the positive blood samples for subgroup typing via RT-PCR, and the representative gp85 genes were sequenced and analyzed.
Results The positive rate of p27 antigen was 32.95% (115/349, ranging from 15.38% to 48.00% across different sites), resulting in an overall ALV nucleic acid positive rate of 31.23% (109/349). Subgroups ALV-A (8.31%), ALV-B (29.80%), ALV-D (0.29%), and ALV-E (31.23%) were detected, whereas subgroups ALV-C, ALV-J, and ALV-K were not detected. Co-infection of ALV-B and ALV-E was commonly observed. The nucleotide sequence identities between the representative sequences and the gp85 genes of the reference strains were 96.1%-98.9% (ALV-A), 81.6%-86.2% (ALV-B), 90.5% (ALV-D), and 99.0%-99.7% (ALV-E), respectively.
Conclusion The ALV detection rate in the core production areas of Wuding chickens is relatively high with significant variations among sampling sites. Exogenous ALV is predominantly ALV-B, which exhibits significant genetic variation, while endogenous ALV-E is highly prevalent. Future ALV eradication programs should adopt a strategy involving multi-timepoint and multi-sample testing, combining both antigen and nucleic acid detection.
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