Complete genome sequence and characterization of four Decapod iridescent virus 1 isolates from crab and shrimp.

Decapod iridescent virus 1 (DIV1) is an emerging viral pathogen that infects diverse freshwater and marine crustacean species and causes considerable economic losses that seriously threaten crustacean farming and has caused enormous financial losses in recent years. In this study, we detected DIV1 from diseased crabs, with clinical symptoms such as loss of vitality and white gill filaments with edema, in a Marsupenaeus japonicus and Portunus trituberculatus polyculture pond. Four DIV1 isolates from crab samples (two isolates) and shrimp samples (two isolates) were sequenced and assembled successfully. Molecular characterization and phylogenetic analysis of the four DIV1 isolates were conducted. The DIV1 isolates from crab samples have a close genetic relationship with shrimp DIV1s, indicating the viruses share the same ancestor with those from shrimps. Our study provides valuable insights into disease prevention and control of the shrimp-crab polyculture system.