Shotgun Metagenomic Diagnosis of Unidentified Pathogens in Hepatic Necrosis Samples from Samgye Chickens.

Source: PubMed, NCBI / U.S. National Library of Medicine

Chicken infectious anemia virus (CIAV), infectious bursal disease virus (IBDV), andspp. are major immunosuppressive pathogens in chickens that predispose host to secondary infections, including-associated hepatic necrosis. In this case, shotgun metagenomic sequencing was applied to identifythat could not be isolated by traditional bacterial culture in Samgye chickens. Six 35-day-old Samgye chicken carcasses were submitted for disease diagnosis, histopathological examination, and bacterial and viral isolation/identification were performed. Pooled liver samples were subjected to shotgun metagenomic sequencing to identify microbial composition, virulence factors, and antimicrobial resistance genes. Samgyehickens exhibited dorsal dermatitis, hepatic necrosis, and splenomegaly. Histopathology revealed hepatic necrosis with bacterial colonies and lymphoid depletion. PCR detected CIAV, antigenic variant IBDV, chicken astrovirus, and, whereas bacterial culture yielded no growth. Shotgun metagenomic analysis identifiedas predominant bacterium, and CIAV as dominant viral pathogen. Theand the antimicrobial resistancegenes were detected from liver samplesThis is the first report of concurrent CIAV, avIBDV,spp., andinfection from Samgye chickens in South Korea, suggesting that immunosuppressive infections may predispose chickens to-associated hepatic necrosis and highlight the diagnostic utility of shotgun metagenomic sequencing.