Phylogenetic analysis of CIAV and pathogenies in embryo eggs.

In this study, clinical samples of positive CIAV were collected for whole genome sequencing, and the key amino acid variation characteristics were analyzed. One of the CIAV was inoculated into 5-day-old embryo eggs to hatch, and the pathogenicity of the isolated virus was systematically evaluated. The results showed that the whole genome of 12 strains of CIAV was sequenced, and there were many amino acid mutation sites in the VP1 gene, mainly concentrated in the hypervariable regions such as 75-97, 139-157, 287-294 and 406-439. The pathogenicity test showed that the weight of chick embryos in the infected group was significantly lower than that in the control group, and the hatching rate decreased. After hatching, chicks showed symptoms such as bursa atrophy, liver bleeding and limb paralysis. HE staining showed pathological changes such as degeneration and necrosis of hepatocytes, lymphocytopenia and renal tubular dilatation. In summary, the molecular characteristics of CIAV epidemic strains in Jiangxi province of China are clarified, which makes up for the shortcomings of the lack of field wild virus background in the existing embryo pathogenicity research.