Fig. 5. Mean cumulative percent mortality of triplicate groups of koi

Fig. 5. Mean cumulative percent mortality of triplicate groups of koi survivors exposed to SVCV (European) or mock infected by intraperitoneal injection for the challenge experiment. The original survivor treatment group in the virulence trial followed by the SVCV (1 × 105 PFU/fish) challenge of each group are listed to the right of graph. No deaths occurred in fish from the mock-challenged groups; mock/mock, IHNV/mock, rIHNV/mock, rIHNV-Gsvcv/mock, and high dose rIHNV-Gsvcv/mock (data not shown). Asterisks delineate mortality levels that were significantly different (p ≤ 0.05) than mortality in the mock/SVCV group. The relative percent survival (RPS) are listed by each group, relative to the mock/SVCV group.

Koi first exposed to a moderate and high dose of a non-virulent recombinant virus (rIHNV-Gsvcv) were then challenged with the wild-type SVC virus to see if they were protected. The original survivor treatment group in the exposure trial followed by the SVCV challenge with each fish being injected with 1 × 105 virus particles of each group are listed to the right of graph. No deaths occurred in fish from the mock-challenged groups (data not shown). Asterisks delineate mortality levels that were significantly different (p ≤ 0.05) than mortality in the mock/SVCV group. The relative percent survival (RPS) are listed by each group, relative to the mock/SVCV group. The high dose of the recombinant virus generated a protective immune response in infected koi, and therefore may be an attractive option for further vaccine development.