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RESEARCH HIGHLIGHTSInclusion body hepatitis (IBH) is an economically important viral disease primarily affecting the poultry industry. In this study, we isolated a strain of FAdV-8b (strain SDYT) from naturally infected ducks and the hexon and fiber gene sequences were analysed by polymerase chain reaction (PCR) amplification. In order to study the pathogenicity of FAdV-8b in Cherry Valley ducks, we inoculated 10- and 20-day-old ducks with 0.3 ml of FAdV-4 virus (TCID50 of 105.5/0.1 ml) either orally or intramuscularly. Clinical signs, gross lesions and histopathological changes, cytokines, viral load and antibody levels were observed and recorded within 15 days after infection. Pathomorphological investigations revealed that ducks in the experimental group exhibited hepatitis. Histopathology showed multiple organ damage, including serious liver and kidney lesions. Furthermore, elevated levels of inflammatory cytokines and antibodies were noticed, due to the infection and innate immune response. At a later stage of infection, immunosuppression occurred, resulting in decreased levels of cytokines. Determination of viral load showed that the virus was present in several organs, with the highest viral DNA load found in the liver, followed by the kidney. Compared to birds infected orally, the intramuscular group exhibited the highest viral load. In summary, this study increases our understanding of the pathogenicity of FAdV-8b in ducks and establishes a model that will inform antiviral drug testing and vaccine evaluation for IBH, thereby preventing and reducing the spread of IBH in the poultry industry.A strain (SDYT) of fowl adenovirus 8b (FAdV-8b) was successfully isolated from ducks.Cherry Valley ducks were successfully infected with FAdV-8b.Different routes of infection can lead to duck mortality, more pronounced when birds are injected intramuscularly.FAdV-8b (SDYT) was distributed in various tissues and organs of ducks, causing different degrees of lesions.A strain (SDYT) of fowl adenovirus 8b (FAdV-8b) was successfully isolated from ducks.Cherry Valley ducks were successfully infected with FAdV-8b.Different routes of infection can lead to duck mortality, more pronounced when birds are injected intramuscularly.FAdV-8b (SDYT) was distributed in various tissues and organs of ducks, causing different degrees of lesions. [ABSTRACT FROM AUTHOR]

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]

In order to study the effects of different irrigation amounts on the root characteristics and yield of cotton without film mulching (abbreviated as filmless cotton) under drip irrigation in Southern Xinjiang, five irrigation amounts of filmless cotton (300, 375, 450, 525 and 600 mm, represented by W1, W2, W3, W4 and W5) and one irrigation amount of cotton with film mulching (abbreviated as filmed cotton) (450 mm, represented by WCK) were set. The effects of irrigation amount on root length density (RLD), root surface area (RSA), root average diameter (RAD), root volume (RV), root weight density (RED) and yield of filmless cotton were analyzed. The results of the two-year experiment showed the following: (1) The indexes of cotton root growth reached the maximum at the flowering and bolling stage, and the growth of soil root in the periphery (30 cm from the main root) and the lower layer (40–60 cm soil layer) reached the peak at the flowering and bolling stages, respectively; (2) The average value of root growth index of film-free cotton in each treatment was W2 > W3 > W4 > W5 and W1. The RLD of W2 and W3 increased by 19.41–106.67% and 13.66–84.22% in the peripheral and lower soil layer, and the proportion of RSA in the peripheral and middle soil layer (20–40 cm soil layer) increased by 1.64–3.41% and 0.49–4.09% compared with other treatments. The RAD, RV and RWD after W2 treatment were relatively large at various distribution points in the soil, followed by W3 treatment; (3) The average root indexes of WCK were not significantly different from those of W3, but the indexes of the lower soil layer were the smallest, at only 29.18–66.84% of the average value of the non-film mulching treatment, while the root indexes of the surface layer (0–20 cm soil layer) and the surrounding soil were larger, with an increase of 11.43–102.17% and 29.60–111.57%, respectively, compared with the non-film mulching treatment; (4) The seed cotton yield of W3 was the highest in the non-film mulching treatment, reaching 4833.25 kg·hm−2, but was still lower than that of WCK by 27.79%. Conclusion: An appropriate water deficit is conducive to root growth and increases the uniformity of its distribution in the soil layer. The irrigation amount of 375–450 mm for filmless cotton in Southern Xinjiang can promote root growth, prevent senescence and increase yield, which can be used as a reference in production. [ABSTRACT FROM AUTHOR]

Duck circovirus (DuCV) is one of the most prevalent infectious viruses in the duck industry in China. Although the clinical signs vary, it often causes immunosuppression in the host and leads to secondary infection with other pathogens. Novel goose parvovirus (NGPV) mainly infects ducks and causes short beak and dwarfism syndrome in ducks. However, the incidence of infection in ducks has increased in recent years, and the phenomenon of mixed infection with DuCV is common, resulting in more severe clinical morbidity. However, there are no systematic studies evaluating the presence of mixed infections. In order to investigate the synergistic pathogenicity of DuCV and NGPV co-infection in SPF ducks, a comparative experiment using DuCV and NGPV co-infection and mono-infection bird models was established. The results showed that the clinical signs of short beak, dwarfism and immunosuppression were more obvious in DuCV and NGPV co-infected ducks; the tissue damage of target organs was more serious, and the viral titre in organs and cloacal swabs were more significant compared with those of SPF ducks infected with only one virus. The results indicated that co-infection with DuCV and NGPV could promote viral replication and cause more severe tissue damage and immunosuppression than single virus infection. The present study reveals that the co-infection of NGPV and DuCV has a synergistic pathogenic effect from the aspect of pathogenicity, and the conclusions drawn not only clarify the direction of the subsequent research on the mechanism of co-infection of NGPV and DuCV, but also provide a scientific basis for the research on the co-infection of immunosuppressive pathogens and other pathogens. [ABSTRACT FROM AUTHOR]

Duckviral hepatitis (DVH) is a highly lethal and highly transmissible viral infectious disease of ducklings caused by the Duck Hepatitis A virus (DHAV), which is characterized by clinical neurological symptoms and liver enlargement with spot-like hemorrhages. In recent years, the change in diagnosis, prevention, and control of the disease has brought great challenges due to the mutation and recombination of epidemic strains, outbreaks and epidemics of genotype 3 (DHAV-3), and the rising trend of mixed infections. Here, we review DHAV on aspects of molecular biological characteristics, epidemiology, pathologic changes, pathogenesis, diagnosis, prevention, and control of the DVH to provide a scientific basis for basic and applied research in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)