Fig. 4. Cumulative mortality of rainbow trout (1.5 g mean weight) challenged by immersion with 5 105 TCID50 mL1 of IPNV. The fish (n ¼ 20 in duplicate tanks) were (A) mockvaccinated
with commercial food pellets and infected with IPNV, (B) mock-vaccinated with the empty pcDNA plasmid and infected with IPNV; (C, D) fed pellets incorporating the
pcDNA-VP2 vaccine on 3 consecutive days and infected with IPNV; (E, F) pcDNA-VP2 vaccine individually administered by pipette tip.