Complete genome sequence and analysis of ictalurid herpesvirus 2

Ictalurid herpesvirus 2 (IcHV-2) has been causing substantial losses in the black bullhead aquaculture industry since the 1990s. Using next-generation sequencing, the genome of IcHV-2 was completely sequenced and analysed in this study. The complete genome was found to be 142,925 bp in size, containing 77 predicted protein-coding regions, including 12 ORFs that appear to have a homologue in every alloherpesvirus genome sequenced to date. The genome organization of the IcHV-2 shows high similarity to that of IcHV-1, the founding member of the genus Ictalurivirus within the family Alloherpesviridae. A unique sequence region of 101 kbp is flanked by terminal direct repeats of 20 kbp. Thirteen of the 77 putative genes do not show homology to any known genes with sequences in public databases; six of them are found in the repeat regions. Analysis of the whole genome confirms the previously established taxonomic position of IcHV-2.