Abstract
Chicken astrovirus (CAstV) infection is strongly associated with kidney disease, gout, “white chicks” hatchery disease, and runting and stunting syndrome (RSS). In the present study, 82.5% of 154 clinical samples from different provinces in China were positive for CAstV by RT-PCR. One CAstV isolate, designated as AAstV/Chicken/CHN/2017/NJ01, was successfully isolated from the small intestine of “Yellow” chickens using LMH cells. The genome sequence and structure analyses revealed that NJ1701 had the typical characteristics of avian astroviruses which was genetically distinct from other Avastrovirus. This isolate was classified as Group B subgroup i based on phylogenetic analysis of complete ORF2 (capsid) amino acid sequences. Meanwhile, growth depression and hatchability reduction were observed in the chicken embryo infection experiment. The results in the current study will contribute to our understanding of chicken astrovirus in China.
Highlights
Astroviruses, belonging to the Astroviridae, are non-enveloped with a positive-sense, single-stranded RNA genome
Subsequent phylogenetic analysis based on partial RNA-dependent RNA polymerase (RdRp) gene sequence revealed that five of seven sequences including NJ1701 belonged to Group II of Avastrovirus according to the classification criteria of previous publication [15]
At 48 h post infection (p.i.) detached small and round cells were predominant, representing almost 100% cytopathic effect (CPE) (Figure 1A), which is similar to the CPE described by Kang et al [20]. quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) showed a significant increase in viral RNA from 24 to 48 h p.i. (Figure 1B)
Summary
Astroviruses, belonging to the Astroviridae, are non-enveloped with a positive-sense, single-stranded RNA genome. The virus particles are 28–30 nm with a star-like morphology. Human astrovirus was first described in 1975, the morphology of the virus particles was not described until 2008 [4, 5]. According to all published full-length sequences, the general genome organization of astroviruses is arranged in the order of 5′-non-coding region, ORF1a/ORF1b, ORF2, and 3′-non-coding region. The astrovirus non-structural proteins are encoded by ORF1a and ORF1b together, including a serine protease, a viral genome-linked protein (VPg), and an RNA-dependent RNA polymerase (RdRp). ORF2 encodes the capsid protein (CP), and the genetic distances of amino acid based on the analysis of the aa sequence of ORF2 is usually used for astrovirus species demarcation [1, 6]
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