Molecular characterization of chicken infectious anemia viruses detected from breeder and broiler chickens in South Korea

In South Korea, 32 sequences of chicken infectious anemia virus (CIAV) from various flocks of breeder and commercial chickens were genetically char- acterized for the first time. Phylogenetic analysis of the viral protein 1 gene, including a hypervariable re- gion of the CIAV genome, indicated that Korean CIAV strains were separated into groups II, IIIa, and IIIb. Strains were commonly identified in great-grandparent and grandparent breeder farms as well as commercial chicken farms. In the field, CIAV strains from breed- er farms had no clinical effects, but commercial farm strains were associated with depression, growth retar- dation, and anemia regardless of the group from which the strain originated. In addition, we identified 7 CIAV genomes that were similar to vaccine strains from vacci- nated and unvaccinated breeder flocks. These data sug- gest that further studies on pathogenicity and vaccine efficacy against the different CIAV group are needed, along with continuous CIAV surveillance and genetic analysis at breeder farms.