Molecular characterization of a porcine astrovirus strain in China

Abstract

Pigs are increasingly recognized to harbor a wide range of viruses that apparently establish long-term persistence in these animals. They serve as reservoirs for a number of human zoonotic diseases. In this study, a porcine astrovirus (PAstV) strain, designated as PAstV JWH-1, is identified from a diarrheal pig in China, and it is partially characterized genetically. Sequence analysis shows that the PAstV JWH-1 strain contains divergent nucleotide sequences in both the open reading frame (ORF)1b/ORF2 consensus and the 3'-UTR regions (s2m motif), which are usually highly conserved among members of the family Astroviridae. Phylogenetic analysis indicates that the JWH-1 strain clusters closely with newly identified strains PAstV 12-4 and 14-4 and forms a group of mamastroviruses with the proposed novel deer astrovirus. Further recombination analysis shows that two possible interspecies recombination events between porcine and deer astroviruses occurred in the genome of the JWH-1 strain. This study further confirms that multiple lineages are present among PAstVs, and each lineage likely represents an independent origin. Additionally, the possibility of interspecies transmission among PAstVs is also suggested.

Adaptive Immunity Restricts Replication of Novel Murine Astroviruses

“…The significance of the viruses within this putative new genogroup remains to be seen. At least one strain within this new putative genogroup has been associated with diarrheal disease in its host (36), suggesting that members of this proposed genogroup may have the potential to exhibit signs of classical human astrovirus disease.…”

Human Astroviruses

“…Indeed, some of the officially recognized AstV species (genotypes MAstV 2, AAstV 1, AAstV 2, and AAstV 3) may infect more than one animal species, indicating that cross-species transmission is frequent, especially in avian viruses. While cross-species infections have been well documented in poultry (160,161) and have also been suggested in mammals, especially in pigs, cats, and humans (147,159,162,163), it is still unclear whether avian viruses may be able to infect mammal species and vice versa. Interestingly, especially within viruses infecting humans, the distinct evolutionary relationships among the different genotype species that infect humans indicate that several introductions of HAstVs into the human population have occurred (31).…”

“…So far, recombination events involving human strains have been suggested to have occurred between classic HAstV and a California sea lion AstV (18) and between classic HAstV and PAstV (163). Recombinations between different animal AstVs have also been described (152,155,162,183). Although most recombination breakpoints have been identified upstream of the conserved ORF1b/ORF2 junction region (155,168,172,182), they are also frequent within ORF2 (152,155,172,177), and they may also exist within ORF1a (155,181) and ORF1b (155,177,180).…”

“…To date, the ICTV officially recognizes only one PAstV genotype (MAstV 3), but at least five genetic lineages which would eventually correspond to genotypes have been documented (162,(185)(186)(187)(188) (Fig. 6, dark blue).…”

Complete Genome of a Novel Porcine Astrovirus

“…The family Astroviridae consists of two genera, Mamastrovirus and Avastrovirus, whose members infect humans, swine, sheep, deer, mink, dogs, sea lions, bats, ducks, pigeons, chickens, and turkeys (1, 2, 5-7, 9, 10, 12, 15, 16, 19-24). Recently, a group of novel astroviruses which were highly diverse was identified in humans and swine (3,4,8,11,14,18). To enlarge the numbers of sequenced porcine astroviruses (PoAstVs), this study describes a complete genome of a novel porcine astrovirus in China.…”