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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]

Cherry Valley breeder ducks in Shandong province in northern China have experienced swollen eyes, lachrymation, pox scabs on glabrous or glabrous skin, depression and dysentery since 2021. The spread of this infectious disease has seriously affected the breeder ducks in major Cherry Valley duck farms in China. The virus causing clinical signs in Cherry Valley breeder ducks was isolated by chicken embryo inoculation. We successfully isolated a strain of duck pox virus from diseased breeder ducks by virus replication. We have also successfully conducted experiments for duck pox disease using the isolated strains to infect ducklings. By comparison with 22 pox viruses already published in GenBank, the virus strain obtained in this study was most homologous (about 99.7%) to the strain isolated from infected domestic ducks in Guangxi, China in 2014 (KJ192189), and belonged to the same A5 subtype. Since there were no previous cases of avian pox virus infecting white or Cherry Valley duck breeds, this study identified a new host for avian pox virus infection and provided theoretical support and data for the development of avian pox virus research. RESEARCH HIGHLIGHTS Avian pox virus can infect a new host type – Cherry Valley breeder ducks. The avian pox virus isolated from Cherry Valley breeder ducks showed highest identity with Guangxi hemp duck-derived avian pox virus. Cherry Valley breeder ducks were infected with avian pox virus of subtype A5. [ABSTRACT FROM AUTHOR]