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Outbreaks of fowl adenoviruses (FAdVs) infection with the main clinical signs of hepatitis-hydropericardium-syndrome or inclusion body hepatitis have been frequently reported in ducks and geese in recent years, causing economic losses for the Chinese waterfowl industry. This study investigated 792 samples (391 fattening ducks, 192 breeder ducks and 209 fattening geese) of suspected FAdV-infected waterfowl from 38 farms (21 fattening duck farms, nine breeder duck farms and eight fattening geese farms) in Shandong Province between 2019 and 2022. The results showed a 60.23% infection rate for FAdVs (477/792), while the infection rate for breeder ducks was almost the same as that for fattening geese (55.73% vs. 54.55%). Notably, co-infection with avian influenza virus H9N2 (H9N2), Tembusu virus (TMUV), duck hepatitis virus (DHV), duck circovirus (DuCV), goose astrovirus (GAstV) and duck parvovirus (DPV)/goose parvovirus (GPV) was common among the 477 FAdVs positive cases. Phylogenetic analysis of complete hexon genes of 22 FAdV strains in Shandong Province showed the presence of four species (FAdV-A, C, D, E) and five serotypes (FAdV-1, 4, 8a, 8b, 11). These findings provide the first data on the prevalence and co-infection status of FAdVs in Shandong Province and can be used as a basis for FAdV prevention in the field. Samples of suspected FAdV-infected waterfowl from farms in Shandong Province were collected from 2019 to 2022. Single infections with FAdV were less frequent than mixed infections. 477 out of 792 samples (60.23%) tested positive for FAdV nucleic acids. Detection rate of FAdV was 65.47% in fattening duck farms, 55.73% in breeder duck farms and 54.55% in fattening geese farms. [ABSTRACT FROM AUTHOR]

Novel duck orthoreovirus can infect various hosts, mainly causing spleen necrosis and hemorrhagic necrotizing hepatitis, leading to immunosuppression and growth impairment. Infectious diseases characterized by swollen hock joints, movement disorders, and impaired growths have recently occurred in significant duck breeding areas in China. Infected ducks from Shandong Province were selected, and N-DRV-LY20 was isolated from the swollen joints. Next-generation sequencing (NGS) of N-DRV-LY20 and homology analysis showed that all ten fragments had the highest homology to N-DRV and the closest affinity to Duck/N-DRV-XT18/China/2018. After artificial inoculation with N-DRV-LY20 virus solution, Cherry Valley ducks showed the same symptoms of leg swelling and hock joint deformation, which were not explored in previous studies. A long history of evolution has led to significant variation in DRV and altered its pathogenicity. In this study, we confirmed the ability of N-DRV to cause viral arthritis in ducks and clarified this isolate's genetic characteristics and level of variation, providing a basis for the control and variation detection of N-DRV. [ABSTRACT FROM AUTHOR]

Goose astrovirus genotype 2 (GoAstV2), as a contagious pathogen of fatal visceral gout in goslings, has been widely distributed in major goose-producing regions in China since 2017, leading to significant economic losses to the Chinese goose industry. In this study, a novel goose astrovirus (GoAstV-SDHZ) was isolated and identified from laying hens with nephritis for the first time. Phylogenetic analysis of the sequenced genome of ORF2 gene revealed that the GoAstV-SDHZ strain clustered into Group 2 GoAstVs and shared the highest identity with the other representative GoAstV2 in the nucleotide (ORF1a: 97.2–99.7%; ORF1b: 98.4–99.8%; ORF2: 97.2–99.9%) and amino acid sequence (ORF1a: 98.2–100%; ORF1b: 98.8–99.6%; ORF2: 97.4–99.6%). In summary, this study provides the first evidence of the GoAstV2 infection in Chinese laying hens, which raises potential threat to the poultry industry in China. [ABSTRACT FROM AUTHOR]

A field isolate (Reo/SDWF /Pheasant/17608/20) of avian orthoreovirus (ARV), isolated from a flock of game-pheasants in Weifang, Shandong Province, was genetically characterized being a field variant or novel strain in our recent research studies in conducting whole genome sequencing by using Next-Generation Sequencing (NGS) technique on Illumina MiSeq platform. Among a total of 870,197 35-151-mer sequencing reads, 297,711 reads (34.21%) were identified as ARV sequences. The de novo assembly of the ARV reads resulted in generation of 10 ARV-related contigs with the average sequencing coverage from 1390× to 1977× according to 10 ARV genome segments. The complete genomes of this pheasant-origin ARV (Reo/SDWF /Pheasant/17608/20) were 23,495 bp in length and consist of 10 dsRNA segments ranged from 1192 bp (S4) to 3958 bp (L1) encoding 12 viral proteins. Sequence comparison between the SDWF17608 and classic ARV reference strains revealed that 58.1–100% nucleotide (nt) identities and 51.4–100% amino acid (aa) identities were in genome segment coding genes. The 10 RNA segments had conversed termini at 5' (5'-GCUUUU) and 3' (UCAUC-3') side, which were identical to the most published ARV strains. Phylogenetic analysis revealed that this pheasant ARV field variant was closely related with chicken ARV strains in 7 genome segment genes, but it possessed significant sequence divergence in M1, M3 and S2 segments. These findings suggested that this pheasant-origin field variant was a divergent ARV strain and was likely originated from reassortments between different chicken ARV strains. [ABSTRACT FROM AUTHOR]

Since the first report from Cherry Valley ducks on a commercial duck farm in China (2008), duck astrovirus type 1(DAstV‐1)‐associated duck viral hepatitis (DVH) have been detected in several commercial duck flocks. A highly acute disease characterized by hepatitis broke out in ducklings in Shandong Province in March 2021, all diseased ducks have been immunized against the duck viral hepatitis vaccine. One DAstV‐1 strain, designated as DAstV‐SDWF, was isolated from a diseased duckling. Here, the isolation, cultivation, and characterization of DAstV‐1 isolate are described. The isolated astrovirus grew well in the LMH cell line. To determine the entire genomic of the DAstV‐SDWF isolate, the next‐generation sequencing (NGS) technique was conducted on the Illumina HiSeq platform. Complete genome sequence analysis revealed that DAstV‐SDWF isolate was 91.6%–98.6% homology with others DAstV‐1 deposited in Genbank. Similar clinical symptoms were successfully reproduced by an experimental infection study using the DAstV‐SDWF isolate. DAstV‐SDWF is the first DAstV‐1 strain whose experimental infection study has been conducted in China. Results of the above data demonstrated that DAstV‐1 could be one of the causative agents of the DVH occurring in China. The present works are likely to provide new insights into the pathogenicity and evolution of DAstV‐1 in ducks. [ABSTRACT FROM AUTHOR]

Since 2013, there have been an increasing number of cases of arthritis in broilers caused by avian orthoreovirus (ARV) in China, and the virus remains highly virulent in chicks with high‐level maternal antibodies. However, little information is available about the complete gene analysis and pathogenicity of the epidemic ARVs. In the study, the ARV strain (V‐ARV‐SD26) was isolated from broilers associated with arthritis in Shandong Province. To genetically characterize the ARV strain, the whole‐genome sequencing was conducted by next‐generation sequencing (NGS) technique. Sequence analysis demonstrated that V‐ARV‐SD26 might have acquired its current genomic composition through several homologous and, in case of the λC, μA and σB, divergent reassortment events. To further investigate the pathogenicity of the strain, 160 one‐day‐old Ross broilers with maternal antibodies were equally divided into four groups (foodpad‐, eye mucosa‐ and intramuscular‐inoculated groups and the negative control group), three experimental groups were inoculated separately with the low‐dose virus fluid, and the negative control was equally inoculated with sterile PBS. The results showed that the symptoms of broilers in foodpad inoculation group were the most serious, while that of the eye mucosa infection group were the mildest. Meanwhile, the cloacal cotton swabs and organs were collected for qRT‐PCR detection to evaluate the infection status. In conclusion, these findings indicate that V‐ARV‐SD26 is a divergent ARV strain, which provide experimental data for the prevention and control of newly emerged reovirus, and have a certain reference value for the preparation and evaluation of new vaccines. [ABSTRACT FROM AUTHOR]

Fowl adenovirus mainly causes hydropericardium hepatitis syndrome (HHS), inclusion body hepatitis (IBH) and gizzard erosion (GE), etc. In 2015, the first outbreak of HHS was reported in broiler chickens in central China, followed by an outbreak in waterfowl. The first outbreak of HHS in broiler flocks in central China in 2015, followed by outbreaks in waterfowl, has severely restricted the healthy development of the poultry industry. During the investigation, fowl adenovirus was detected in ducklings from a total of seven hatcheries in Shandong, Inner Mongolia and Jiangsu provinces. In addition, the DNA of fowl adenovirus was detected in breeding ducks and their progeny. To test the hypothesis that FAdV can be transmitted vertically, sixty 250-day-old Cherry Valley breeder ducks were divided equally into three groups for experimental infection. FAdV-8b SDLY isolate (duck/Shandong/SDLY/2021, SDLY) preserved in our laboratory was injected intramuscularly into group A and inoculated orally into group B. FAdV-8b DNA was detected in the yolk membranes, embryos and allantoic fluid of duck embryos in the FAdV-infected group after inoculation. In addition, the FAdV-8b hexon gene isolated from yolk membranes, embryos, allantoic fluid and duck eggs was close to 100% nucleotide homology to the FAdV-8b hexon gene isolated from laying duck ovaries, indicating that fowl adenovirus can be transmitted vertically in ducks. These findings provide evidence for the possible vertical transmission of fowl adenovirus from breeder ducks to ducklings. • A high prevalence of FAdVs was observed in breeding duck flocks. • Sixty 250-day-old Cherry Valley breeder ducks were randomly divided into three groups for experimental infection. • After the inoculation, FAdV-8b could be detected in anal swabs of the infected groups. • FAdV-8b DNA can be detected in the offspring hatched after infection, and some clinical symptoms can be observed. • FAdV-8b may be transmitted vertically in breeding ducks. [ABSTRACT FROM AUTHOR]