Isolation and characterization of a novel chicken astrovirus in China

Chicken astrovirus (CAstV) is associated with kidney disease and visceral gout, runting and stunting syndrome, and white chick hatchery disease, causing economic losses to the poultry industry worldwide. In this study, 55.6% of 36 clinical samples from Guangdong province in China were positive for CAstV, but negative for other common enteric viruses, including avian nephritis virus, infectious bronchitis virus, fowl adenovirus Group I, Newcastle disease virus, chicken parvovirus, reovirus, and rotavirus by PCRs and RT-PCRs. A CAstV strain, named GD202013, was isolated from Guangdong province in south China, and was identified by CAstV RT-PCR. A whole genome sequence analysis demonstrated that GD202013 shares 76.0 to 88.1% identity with 24 reference strains in GenBank. Phylogenetic analysis, based on whole genome and capsid protein, showed that GD202013 is more closely related to 2 US strains (GA2011/US/2011 and 4175/US/2011) belonging to subgroup Bii. Recombination analysis indicated that GD202013 is a recombinant strain formed by 3 strains: a major parent strain CkP5/US/2016, and 2 minor parent strains (GA2011/US/2011 and G059/PL/2014). In addition, the chicken embryo infection experiment demonstrated that GD202013 causes hatchability reduction, growth depression, and death of embryos. Macroscopic and microscopic lesions in the liver, kidney and small intestine were observed in the dead-in-shell embryos. This is the first report of the novel CAstV infection in China.