Complete genomic sequence of a duck enteritis virus attenuated via serial passage in chick embryos.

Here, we present the complete genomic sequence of an attenuated duck enteritis virus (DEV). The Chinese standard challenge strain of DEV (DEV CSC) was serially passaged 20 times in chick embryo fibroblasts and then 85 times in chick embryos. The virus was attenuated and was avirulent to 2-month-old ducks. The attenuated DEV genome is 162,131 base pairs (bp) in length and as long as the parental genomic sequence. There are only 22 nucleotide substitutions, resulting in single amino acid changes in open reading frames LORF5, LORF4, UL41, UL39, UL32, UL13, UL10, UL3, US3, US4 and US7. The genome sequence has been deposited in the GenBank database under accession number KU216226. This study provides genetic information about DEV attenuation and further advances our understanding of the molecular basis of DEV pathogenesis.