show Abstracthide AbstractDuring viral infection, a large number of immune response signaling molecules including the interferon regulatory (IRF) family and type I interferon (IFN) transcribe. The exact identity and expression levels of fish IRFs and type-I IFNs during viral infection remains largely unknown. Here, we utilized Illumina sequencing technology to determine differential expression patterns for both zebrafish IRFs and type-I IFNs during two stages of SVCV infection, i.e. 6h and 24h post-infection. For 12 zebrafish IRFs, we identified DrIRF1 mRNA as one of the most abundant in normal tissues and also in SVCV-infected tissues, but DrIRF11 had a very weak basal expression and was almost not induced by SVCV infection. We also identified the highly basal expression of DrIRF7, which together with DrIRF3, was highly induced by SVCV infection. For type-I IFNs, zebrafish has four IFN genes, three of which, IFN1/2/3, particularly IFN 1 and IFN 3, were significantly transcribed under the same conditions. Overall design: 12 adult healthy male and female (1:1) zebrafish were infected by intraperitoneal inoculation with approximately 50 µL SVCV (10-8TCID50/mL). 6 infected fish (male:female=1:1) were sacrificed at 6h post-injection, and 6 (male:female=1:1) were sacrificed at 24h post-injection for head kidney (6K and 24K) and spleen (6S and 24S). Head kidney and spleen (0K and 0S) from the 6 control adult zebrafish (male:female=1:1) were collected as negative control.