Avian Leukosis Virus (ALV) is a retrovirus that induces immunosuppression and tumor formation in poultry, posing a significant threat to the poultry industry. Currently, there are no effective vaccines or treatments for ALV. Therefore, the early diagnosis of infected flocks and farm sanitation are crucial for controlling outbreaks of this disease. To address the limitations of traditional diagnostic methods, which require sophisticated equipment and skilled personnel, a dual-tube detection method for ALV-J based on reverse transcription isothermal amplification (RAA) and the CRISPR-Cas13a system has been developed. This method offers the advantages of high sensitivity, specificity, and rapidity; it is capable of detecting virus concentrations as low as 5.4 × 10⁰ copies/μL without cross-reactivity with other avian viruses, with a total testing time not exceeding 85 min. The system was applied to 429 clinical samples, resulting in a positivity rate of 15.2% for CRISPR-Cas13a, which was higher than the 14.7% detected by PCR and 14.2% by ELISA, indicating superior detection capability and consistency. Furthermore, the dual-tube RAA-CRISPR detection system provides visually interpretable results, making it suitable for on-site diagnosis in remote farms lacking laboratory facilities. In conclusion, the proposed ALV-J detection method, characterized by its high sensitivity, specificity, and convenience, is expected to be a vital technology for purification efforts against ALV-J.

Avian leukosis (AL), a major vertically transmitted infectious disease, poses a significant challenge to the conservation and industrial development of indigenous chicken breeds in China. In this study, Chengkou mountain chickens were used as a model to systematically identify genetic markers associated with resistance to avian leukosis virus subgroup J (ALV-J) through a genome-wide association study (GWAS). Genomic DNA was extracted from 500 hens at 300 days of age, and cloacal swabs, plasma, and egg white samples were collected to assess the ALV-J infection status. A total of 325 ALV-positive (ALV+) and 175 ALV-negative (ALV−) individuals were identified. Based on 10× whole-genome resequencing and stringent quality control, 12,644,463 high-quality SNPs were obtained. GWAS revealed a significant enrichment of SNPs on chromosome 6 (Chr6), from which 218 SNPs significantly associated with ALV-J resistance and 49 candidate genes were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that many of these genes, including PTPN13, TTF2, TIAL1, DLG2, FBXL7, CDH5, and CDH11, are involved in tumorigenesis and immunosuppression through the JAK/STAT signaling pathway and cell adhesion molecule pathways. Additionally, candidate genes, such as ANKH, SLC4A7, and SLC5A1, were found to potentially regulate ALV-J infection by modulating membrane transport and inflammatory responses. This study is the first to identify ALV-J resistance-associated genetic markers in Chengkou mountain chickens, revealing key genes related to immune regulation, membrane function, and tumor development. The findings provide a foundational molecular basis for disease-resistant breeding in poultry.