The envelope glycoprotein gene and pre-membrane proteins of duck tembusu virus (DTMUV) as well as the hemagglutinin gene of highly pathogenic avian influenza virus (HPAIV) H5N1 were inserted at the suited sites in C-KCE strain to develop a trivalent vaccine that can efficiently prevent the infection of DTMUV, H5N1, and DEV in ducks.5 In addition to targeting DNA viruses, CRISPR-Cas9 system demonstrated its feasibility and versatility in targeting RNA viruses. This evidence concerns the gene ERVW-1 and infection.