Since February 2017, severe outbreaks of fatal gout caused by novel gosling astroviruses (GoAstVs) have occurred in several Chinese provinces, causing a considerable economic impact on the poultry industry. To assess the infection status of GoAstVs causing gout, 165 clinical samples were collected from goslings from seven farms located in different Chinese provinces, and they were screened for viral infection. Seven GoAstV strains were completely sequenced. The positive infection rates of GoAstV, goose parvovirus, reovirus, goose haemorrhagic polyomavirus and Tembusu virus were 100%, 9.69%, 3.64%, 0% and 0%, respectively, indicating the role of GoAstV in gout. The genomes of all seven GoAstV strains were 7170‐nt long and encoded three open reading frames (ORFs), namely, ORF1a, ORF1b and ORF2. Sequence and phylogenetic analyses of the seven GoAstV strains showed that these were avastroviruses and were closely related to viruses classified within Avastrovirus 3 and turkey astrovirus 2. Moreover, the mutation rates of ORF1a and ORF2 were high, and ORF1a was highly mutated at amino acid loci 545–580. The tertiary structure of the mutated ORF2 protein was smooth, and its antigenic epitope was highly mutated, which may be related to the pathogenicity of the virus and caused by antibody pressure from the host. These findings enrich our understanding of the evolution of novel GoAstVs causing gout and their circulation as well as lay the foundation for the selection of vaccine strains.

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Duck circovirus (DuCV) was first identified in mallard ducks with feathering disorder and poor body condition in Germany in 2003

Mycoplasma synoviae ( M. synoviae ) has been identified worldwide to cause respiratory diseases, infectious synovitis, airsacculitis, and eggshell apex abnormalities ( EAA ) in commercial chickens, which results in substantial economic losses to the poultry industry. Therefore, in this study, 258 flocks were investigated between 2017 and 2019 for M. synoviae by screening samples from Central China. Subsequently, 129 M. synoviae strains were isolated, with a positive rate of 50%. Moreover, a higher incidence of M. Synoviae infections was in layers (74.1%) than in broilers (20%) in this study. The 5′-end conserved segment of the variable lipoprotein hemagglutinin A ( vlhA ) gene of these isolates was then cloned and sequenced because it is a common genomic target identified so far for M. synoviae genotyping. Genotyping of all isolates was based on the phylogenetic analysis and length analysis of the proline-rich-repeat ( PRR ) regions, respectively. Phylogenetic analysis based on 5′-end conserved segment of the vlhA gene (76–421 nt) assigned the majority of the occurring strains as being from group 6, and others from groups 2 and 3. Results identified that these isolates were of 6 types: A (38aa), D (23aa), E (19aa), I (28aa), J (20aa), and L (35aa), based on the size of the PRR region analysis. Furthermore, most of the isolates (81.4% were identified as type L. Additionally, the epidemic types included only I and L in 2017; however, the types rose to 5 (A, D, E, I, L) in 2018 and rose to 6 (A, D, E, I, J, L) in 2019. These data showed the genotype diversity of M. synoviae in Central China. The high rate of positive flocks suggests the urgent need to take real-time supervisory controls of this Mycoplasma species in avian flocks.