Construction and evaluation of a recombinant duck enteritis virus expressing the envelope protein of duck Tembusu virus in ducks.

Duck Tembusu virus (DTMUV) poses a significant threat to the waterfowl breeding industry in China. Here, we constructed a recombinant duck enteritis virus (DEV) expressing the entire E protein of DTMUV, named rDEV-ERT, using homologous recombination and the Cre-Lox system. The DTMUV E gene was integrated into the UL2 region of the DEV genome. At 14 days post-vaccination (dpv), 60 TCID50 of rDEV-ERT provided complete protection against lethal DEV challenge. At 28 dpv, the positive rate of DTMUV antibodies induced by rDEV-ERT was 50%, and the protection rate against a virulent DTMUV strain was 62.5%. These findings support the development of a DEV-DTMUV recombinant live vector vaccine.