FIG. 1.
Construction and replication of the recombinant IHNV. (A) Diagram of the rIHNVLUC and rIHNVLUC-ΔNV genomes. An additional cistron encoding the Renilla luciferase (LUC) was inserted between the M and G genes of the wild-type-like IHNV (rIHNV) genome or of the rIHNV-ΔNV/GFP genome (4), leading to rIHNVLUC and rIHNVLUC-ΔNV, respectively. (B) Cumulative mortality induced in virus-infected trout. Juvenile trout (75 fish/tank) were infected by bath immersion with 5 × 104 PFU/ml of each virus. Mortalities were recorded every day and expressed as a percentage of cumulative mortality. d.p.i., day postinfection; IHNV 32-87, wild-type IHNV; rIHNV, wild-type-like recombinant IHNV (4); rIHNVLUC, recombinant IHNV expressing the LUC gene; mock, mock-infected trout. Experimental fish infections were done in triplicate.