[Pathogenicity and genomic sequence comparison of a chicken infectious anemia virus field isolate]

A field strain C14 of chicken infectious anemia virus (CAV) was isolated from a 14 day-old broiler flock with growth runting syndromes. Antibody reactions to inactivated vaccines to avian influenza viruses (AIV) were suppressed in SPF chickens inoculated with C14 strain CAV at 1 day-old. Also C14 strain CAV and reticuloendotheliosis Virus demonstrated a synergism in immunosuppression when chickens were infected with both virus. The viral genomic DNA was amplified by PCR in 3 overlapped fragments and PCR products were cloned into T-vector plasmid for sequencing. The sequencing results indicated that the total genome of C14 strain CAV was 2298bp, it contained 3 overlapped ORF and 1 non-coding regulation fragment. Its whole genome had 97.2% - 99.2% of homogeneity to other several published CAV reference strains. Sequence data indicated that there are many motifs in the non-coding area of about 400bp as the binding sites for transcriptional factors. All these motifs were very conservative. There were some mutations in 3 genes VP1, VP2 and VP3. Relatively, VP1 was less conservative than VP2 and VP3. Among different strains, mutations in these 3 genes were not correlated.