Novel goose astrovirus (NGAstV) is a member of the genus Avain Avastrovirus (AAstV) and the family Astroviridae. NGAstV-associated gout disease has caused huge economic losses to the goose industry worldwide. Since early 2020, NGAstV infections characterized by articular and visceral gout emerged continuously in China. Herein, we isolated a GAstV strain from goslings with fatal gout disease and sequenced its complete genome nucleotide sequence. Then we conducted systematic genetic diversity and evolutionary analysis. The results demonstrated that two genotypic species of GAstV (GAstV-I and GAstV-II) were circulating in China, and GAstV-II sub-genotype IId had become the dominant one. Multiple alignments of amino acid sequences of GAstV capsid protein revealed that several characteristic mutations (E456D, A464N, and L540Q) in GAstV-II d strains, as well as additional residues in the newly identified isolate which varied over time. These findings enrich the understanding of the genetic diversity and evolution of GAstV and may facilitate the development of effective preventive strategies.

The avian immunosuppressive and neoplastic diseases are great threats to the poultry industry, causing huge economic losses worldwide. Most recently, the emerging hypervirulent variants of Marek’s disease virus (HV-MDV), partially co-infected with avian leukosis virus (ALV) and/or reticuloendotheliosis virus (REV), have been identified as the key driver of tumour outbreaks in vaccinated chicken flocks, but the role of chicken infectious anemia virus (CIAV) remains unclear. Herein, we have investigated the prevalence and co-infection of CIAV in 71 clinical tumour-bearing flocks collected from central China during 2021–2023, which has shown a CIAV positivity rate of 59.2% (42/71). Notably, the incidence of CIAV mono-infection increased significantly from 0% (0/29) in 2021 to 23.7% (9/38) in 2023, whereas CIAV + MDV co-infection decreased from 65.5% (19/29) to 31.6% (12/38). A total of 20 viral genomes of epidemic CIAV isolates from diverse sources were obtained, and the phylogenetic analysis, including 91 reference isolates were clustered into four major lineages (A–D), with clade C further subdivided into subclades C1 and C2. Clade C1 consisted predominantly of Asian isolates, with 88.5% (46/52) of the isolates originating from mainland China. Among the 20 new isolates, 17 were clustered in subclade C1, two in C2, and one in B. The VP1 gene phylogeny showed a topology largely consistent with that of the whole-genome analysis. Moreover, all newly characterized isolates contained glutamine (Q) at VP1 residue 394, a molecular marker associated with high pathogenicity. Collectively, our data suggest that prevalent HV-MDV variants together with CIAV co-infections are the primary drivers of the ongoing tumour outbreaks in Chinese poultry flocks. Notably, the significantly increased CIAV mono-infections, possibly resulting from an independently evolving lineage among circulating Chinese strains, are likely to pose a new challenge for future control of disease.

Goose astrovirus (GAstV) is an emerging pathogen that primarily causes gout in goslings under 4 weeks of age, resulting in substantial economic losses to the goose industry in China. In this study, we isolated and identified a GAstV strain, designated GAstV/HNJZ, from infected goslings in Henan Province, China. Infected goslings exhibited typical pathological lesions: the surfaces of the heart, liver, and kidneys were covered with urate membranes, and a “villous heart” was formed due to urate deposits. The kidneys and the joints were swollen. Massive urate deposits were observed in the tarsal and toe joints. Sequence analysis revealed that the complete genome of GAstV/HNJZ isolate was 7,183 nt in length, sharing the highest nucleotide identity (99.6%) with the virulent GAstV strain AAstV/Goose/CHN/2023/HR2306/1 from Anhui Province. Phylogenetic analysis demonstrated that the GAstV/HNJZ isolate belonged to genotype GAstV-II, subgenotype IId, indicating that GAstV-II remains the predominant circulating genotype in China. Several specific amino acid mutations were identified in the N-terminal capsid core domain (H26Q, A228T, A/T289T, and N380S). Selection pressure analysis revealed that Chinese GAstV strains have evolved in a relatively conserved and stable manner. This finding provides a theoretical basis for further research on the pathogenic mechanism, targeted vaccines and antiviral drugs against goose astrovirus.

The widespread distribution and genetic diversity of porcine circovirus type 2 (PCV2) seriously threatens the swine industry worldwide. This study investigates the molecular epidemiology of PCV2 in Henan Province (2020–2023) through PCR screening (385 samples) and whole-genome sequencing (34 strains). The overall detection rate was 71.17% (274/385), with annual rates of 81.16% (112/138) in 2020, 72.41% (84/116) in 2021, 62.50% (55/88) in 2022, and 53.49% (23/43) in 2023, indicating a declining trend. Phylogenetic analysis revealed the dominance of the PCV2d genotype, comprising 82.4% (28/34) of sequenced strains. Evolutionary analysis identified strong negative selection pressure on ORF2, with an elevated substitution rate of 1.098 × 10⁻³ ssy. These findings provide critical insights into the predominance and adaptive evolution of PCV2d, and significantly improve our understanding of its genetic diversity and evolutionary dynamics.

The avian immunosuppressive and neoplastic diseases are great threats to the poultry industry causing huge economic losses worldwide. Most recently, the emerging hypervirulent variants of Marek’s disease virus (HV-MDV), partially co-infected with avian leukosis virus (ALV) and/or reticuloendotheliosis virus (REV), have been identified as the key driver of tumour outbreaks in vaccinated chicken flocks, but the role of chicken infectious anaemia virus (CIAV) remains unclear. Herein, we have investigated the prevalence and co-infection of CIAV in 72 clinical tumour-bearing flocks collected from central China during 2020-2023, which has shown a CIAV positivity rate of 59.7% (43/72). Notably, the incidence of CIAV mono-infection increased significantly from 0% (0/30) in 2020-2021 to 26.2% (11/42) in 2022-2023, whereas CIAV+MDV co-infection decreased from 66.7% (20/30) to 28.6% (12/42). A total of 20 viral genomes of epidemic CIAV isolates from diverse sources were obtained, and the phylogenetic analysis including 91 reference isolates were clustered into four major lineages (A–D), with a clade C further subdivided into subclades C1 and C2. Clade C1 consisted predominantly of Asian isolates, with 88.5% (46/52) of the isolates originated from mainland China. Among the 20 new isolates, 17 were clustered in subclade C1, two in C2, and one in B. The VP1 gene phylogeny showed a topology largely consistent with that of the whole-genome analysis. Moreover, all newly characterized isolates contained glutamine (Q) at VP1 residue 394, a molecular marker associated with high pathogenicity. Collectively, our data suggest that prevalent HV-MDV variants together with CIAV co-infections are the primary drivers of the ongoing tumour outbreaks in Chinese poultry flocks. Furthermore, the increased pathogenicity observed in CIAV mono-infections, likely resulting from an independently evolving lineage among circulating Chinese strains, will pose a significant challenge for future control of disease.

In \cite{JZ1}, D. Jiang and L. Zhang proposed a conjecture which related the wavefront sets and the descent method in the local fields case. Recently, in \cite{JLZ}, they and D. Liu define the arithmetic wavefront set of certain irreducible admissible representation $\pi$ of a classical group $G(k)$ defined over local field $k$, which is a subset of $k$-rational nilpotent orbits of the Lie algebra of $G(k)$, by the arithmetic structures of the enhanced L-parameter of $\pi$. These arithmetic structures are based on the rationality of the local Langlands correspondence and the local Gan-Gross-Prasad conjecture. They also prove that the arithmetic wavefront set is an invariant of $\pi$ (it is independent of the choice of the Whittaker datum \cite[Theorem 1.1]{JLZ}), and propose several conjectures to describe the relationship between arithmetic wavefront sets, analytic wavefront sets and algebraic wavefront sets. In this paper we study wavefront sets of irreducible representations for finite symplectic groups and describe the relationship between wavefront sets, descent method and finite Gan-Gross-Prasad problem. The finite fields case of Gan-Gross-Prasad problem can be calculated explicitly \cite{LW3,Wang1,Wang2}. It allows us to calculate the multiplicity of an irreducible representation in the generalised Gelfand-Graev representation corresponding to certain nilpotent orbits which are finite fields analogies of the arithmetic wavefront sets. In particular, for cuspidal representations, we give certain multiplicity one theorem and show that the finite fields analogy of arithmetic wavefront sets coincides with the wavefront sets in the sense of G. Lusztig and N. Kawanaka.