Decapod iridescent virus 1: An emerging viral pathogen in aquaculture

Decapod iridescent virus 1 (DIV1) is an emerging viral pathogen that seriously threatens crustacean farming and has caused enormous economic losses in recent years. This virus was originally isolated and identified from diseased crayfish Cherax quadricarinatus and shrimp Litopenaeus vannamei in Fujian and Zhejiang, China, in 2014 by two research groups. In 2019, the Executive Committee of the International Committee on Taxonomy of Viruses approved DIV1 as a member of the new genus Decapodiridovirus in the family Iridoviridae. DIV1 is icosahedral in shape and contains a single linear double-stranded DNA genome of approximately 165 kb. DIV1 can infect many host species, including freshwater and seawater crustaceans, but infected hosts do not show unique pre-clinical signs, which increases the difficulties in the diagnosis and treatment of this disease. Increasing progress has been made towards understanding many aspects of this virus, including its classification, genomic features, transmission mode, host range, pathogenicity, clinical symptoms, histopathology, detection method and host immunity in response to infection. In this review, we provide an overview of recent progress towards understanding the epidemiology and pathobiology of disease caused by DIV1 and highlight the future research prospects in control and prevention strategies.