Genomic characteristics, pathogenicity and viral shedding of a novel DVEV variant derived from goose

Duck virus enteritis (DVE), caused by the DVE virus (DVEV), is an acute, septicemic, and contagious disease affecting ducks of different breeds, ages, and sexes. In late spring and summer 2019, several outbreaks of DVE were reported in areas with large waterfowl industries in central and southern China. A goose farm located in Jining County, Shandong Province, was impacted by an acute DVE outbreak in July 2019. The causative DVEV field strain (Goose/DVEV/SDJN/China/2019) was subsequently isolated from the liver specimens collected from acute cases of dead geese, which showed severe hemorrhagic lesions on the esophageal mucosal membranes of specimens collected from all the postmortem cases. Comparison of the genome sequence of this newly isolated field strain (Goose/DVEV/SDJN/China/2019) with the common DVEV strains revealed insertions or mutations in the gB and gC genes, which possibly caused the observed high morbidity and mortality in this acute outbreak. We conducted a trial among geese to evaluate the pathogenicity of this strain. Healthy experimental goslings aged 15 d old were inoculated with 10^-5.53 ELD₅₀/0.2 mL doses orally or through intramuscular injection. Clinical signs and esophageal erosion appeared in infected geese. Necropsy revealed hemorrhage and necrosis of the cloacal mucosa and liver. Detection of the virus using real-time PCR in the liver, brain, and spleen indicated that they were the hotspots of DVEV infections. One day after the DVEV infection, virus release and seroconvert were observed in infected geese. Thus, our studies demonstrate that DVEV is highly pathogenic and contagious in geese. To the best of our knowledge, this is the first study on the pathogenicity of mutant duck viral enteritis virus in goslings. This study serves as a foundation for further investigations into the pathophysiology of the recently identified variant DVEV strains.