ARS | Publication request: Molecular characterization of avian astroviruses

Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 6, 2010
Publication Date: February 1, 2011
Citation: Pantin Jackwood, M.J., Strother, K.O., Zsak, L., Mundt, E., Day, J.M., Spackman, E. 2011. Molecular characterization of avian astroviruses. Archives of Virology. 156(2):235-244.

Interpretive Summary: Astroviruses are frequently associated with enteric diseases and poor growth performance in broiler chickens and turkeys. Five types of avian astrovirus have been identified in poultry species: Turkey Astroviruses 1 and 2 (TAstV-1, TAstV-2), Avian Nephritis Virus (ANV), Chicken Astrovirus (CAstV) and Duck Astrovirus (DAstV). The objective of this study was to characterize the different types of avian astroviruses by sequencing the virus gene that encodes for the capsid protein which is important because it’s associated with serotype and viral pathogenesis. A big variation among the capsid sequences was found within each subtype. The capsid genes of TAstV-2’s were 81.5%-100% similar, of ANV’s were 69.9%-100% similar, and of CAstV’s were 85.3%-97.9% similar. However, this gene was more similar among TAstV-1’s (96.2%-100%). In addition, a novel astrovirus was detected in chicken samples and found to be <64% similar to ANV’s and <30.6% similar to CAstV’s. The results of this study highlight the great genetic variability of avian astroviruses and indicate that there are most likely multiple serotypes of each avian astrovirus are circulating in commercial poultry.

Technical Abstract: Astroviruses are frequently associated with enteric diseases in poultry, being isolated from cases of runting-stunting syndrome (RSS) of broiler chickens, poult enteritis complex (PEC) and poult enteritis mortality syndrome (PEMS) of turkeys. Currently, five types of avian astrovirus have been identified: Turkey Astroviruses 1 and 2 (TAstV-1, TAstV-2), Avian Nephritis Virus (ANV), Chicken Astrovirus (CAstV) and Duck Astrovirus (DAstV). The objective of this study was to molecularly characterize the different types of avian astroviruses circulating in commercial poultry. Sequence analysis of a region of the ORF2, which encodes the capsid precursor protein associated with serotype and viral pathogenesis, revealed extensive variation in amino acid sequence within each subtype: TAstV-2’s (81.5%-100%), ANV’s (69.9%-100%), and CAstV’s (85.3%-97.9%). However, this region was more conserved in TAstV-1’s (96.2%-100%). Furthermore, a novel astrovirus was detected in chicken samples and found to be <64% similar to ANV’s and <30.6% similar to CAstV’s. The results of this study underline the great genetic variability of avian astroviruses and indicate that there are most likely multiple serotypes of each avian astrovirus are circulating in commercial poultry.