Pathogenesis of Chicken Astrovirus Related Illnesses

Abstract

Of the several known viruses, chicken astrovirus (CAstV) has been associated with diarrhea, runting-stunting syndrome, severe kidney disease, and gout, and white chick syndrome (WCS) in young broiler chicks. Discovered in 2004, CAstV consists of two genogroups with an expanding subgroup because of the diversity exhibited in its viral capsid sequence. Despite these findings, there exists a dearth of knowledge on its pathogenesis. This review highlights the pathogenesis and development of in vivo and in vitro models.

Molecular characterization of chicken astrovirus and pathogenicity of a novel isolate in China

“…As the most divergent region of the CAstV genome, ORF2 gene encodes capsid precursor proteins of the viral particle, which is the major determinant of virus antigenicity, immune response, cell tropism and viral pathogenicity ( Smyth et al, 2012 ; Raji and Omar, 2022a , b ). CAstV strains, based on phylogenetic analysis and the genetic distance of the ORF2 amino acid sequences, can be divided into two distinct genogroups (A and B): Group A with three subgroups (Ai, Aii, and Aiii), and Group B consists of six subgroups (Bi, Bii, Biii, Biv, Bv, and Bvi) ( Smyth, 2017 ; Raji et al, 2022 ; Raji and Omar, 2022a , b ). The previous studies have reported that diverse CAstV strains (subgroup Ai, subgroup Bi, subgroup Bii) are detected circulating in Chinese chicken flocks ( Zhao et al, 2020 ; Luan et al, 2022 ).…”

“…Chicken astrovirus (CAstV), belonging to genus Avastrovirus in Astroviridae family, acts as an etiologic agent of enteric disease in chickens, and makes a primarily effect on the poultry industry, and generates economic losses worldwide ( Raji and Omar, 2022a , b ). CAstV is a star-shaped morphology (28–30 nm in diameter), non-enveloped, positive-sense, and single-stranded RNA virus ( Smyth, 2017 ; Raji and Omar, 2022a , b ).…”

“…Chicken astrovirus (CAstV), belonging to genus Avastrovirus in Astroviridae family, acts as an etiologic agent of enteric disease in chickens, and makes a primarily effect on the poultry industry, and generates economic losses worldwide ( Raji and Omar, 2022a , b ). CAstV is a star-shaped morphology (28–30 nm in diameter), non-enveloped, positive-sense, and single-stranded RNA virus ( Smyth, 2017 ; Raji and Omar, 2022a , b ). The around 7.5 kb genome includes one 5′-untranslated region (5’-UTR), one 3′-untranslated region (3’-UTR), and three open reading frames (ORFs), which encode two non-structural proteins designated as trypsin-like serine protease within ORF1a, the RNA-dependent RNA polymerase within ORF1b, and a structural capsid protein within ORF2 ( Kang et al, 2012 ; Cortez et al, 2017 ).…”

“…As the most divergent region of the whole genome, the ORF2 gene encodes one surface protein of viral particles and is accountable for the virus antigenicity, cell tropism, pathogenicity, and immune protection ( Smyth et al, 2012 ; Smyth, 2017 ). According to the capsid protein, CAstV strains can be categorized into two distinct genogroups: Group A (three subgroups: Ai, Aii, and Aiii) and Group B (six subgroups: Bi, Bii, Biii, Biv, Bv, and Bvi) ( Smyth, 2017 ; Raji et al, 2022 ; Raji and Omar, 2022a , b ).…”

“…CAstV was initially identified from broiler flocks with uneven growth and runting-stunting syndrome in the Netherlands in 2004 ( Baxendale and Mebatsion, 2004 ), and then emerged in many countries globally ( Pantin-Jackwood et al, 2011 ; Smyth, 2017 ; Xue et al, 2017 , 2020 ; Raji and Omar, 2022a , b ). CAstV is transmitted both vertically and horizontally and can often infect chickens at an early age ( Koci and Schultz-Cherry, 2002 ; Smyth, 2017 ).…”