Construction of the recombinant duck enteritis virus delivering capsid protein VP0 of the duck hepatitis A virus.

Duck hepatitis A virus type 1 (DHAV-1) disease causes significant economic losses to the duck industry. Duck enteritis virus (DEV) is frequently used as a viral vector for aquatic poultry vaccination, but no recombinan DEV expressing DHAV-1 VP0 has been developed. In this study, we established a system for rescuing the DEV C-KCE vaccine strain by transfecting cells with six fosmid DNAs. We generated a recombinant virus (rDEV-ul41VP0) by inserting the VP0 gene of DHAV-1 into the ul41 region in the DEV C-KCE genome. DHAV-1 VP0 was stably expressed in the rDEV-ul41VP0 infected cells, but did not affect the replication properties of DEV C-KCE in cells. Duck experiments showed that rDEV-ul41VP0 could provided full protection against the lethal DEV Chinese standard challenge (DEV CSC) and conferred 70% protection against DHAV-1 161/79 at 3 days postvaccination. These results indicate that rDEV-ul41VP0 rapidly induces protection against DEV CSC and DHAV-1 in ducks, and can be served as a bivalent vaccine against DEV and DHAV-1.