Genetic Heterogeneity among Chicken Infectious Anemia Viruses Detected in Italian Fowl

SIMPLE SUMMARY: Chicken infectious anemia virus (CIAV) is an immunosuppressive pathogen of chickens. In the present study field, vaccine-derived CIAV strains were reported to circulate in different types of chicken flocks. Viruses were successfully obtained from non-invasive samples such as feathers and environmental dust. Genome analysis showed that strains had heterogeneous sequences clustered into different genogroups that possessed genetic markers reported to be correlated with CIAV virulence. This survey contributes to the knowledge of field CIAV distribution maps and increases the existing information available on native isolates around the world. ABSTRACT: Chicken infectious anemia virus (CIAV) is a pathogen of chickens associated with immunosuppression and with a disease named chicken infectious anemia. The present survey reports an epidemiological study on CIAV distribution in Italian broiler, broiler breeder and backyard chicken flocks. Twenty-five strains were detected by a specifically developed nested PCR protocol, and molecularly characterized by partial VP1 gene or complete genome sequencing. Viral DNA amplification was successfully obtained from non-invasive samples such as feathers and environmental dust. Sequence and phylogenetic analysis showed the circulation of field or potentially vaccine-derived strains with heterogeneous sequences clustered into genogroups II, IIIa, and IIIb. Marker genome positions, reported to be correlated with CIAV virulence, were evaluated in field strains. In conclusion, this is the first survey focused on the molecular characteristics of Italian CIAVs, which have proved to be highly heterogeneous, implementing at the same time a distribution map of field viruses worldwide.