The glycoprotein, non-virion protein, and polymerase of viral hemorrhagic septicemia virus are not determinants of host-specific virulence in rainbow trout

Table 3 Summary results for in vivo challenge experiments

Treatment Group	Individual tank final CPM^a	Ave. final CPM	Mean day to death±SD^b	Day 7 infection, # pos/# tested (# > inoculum)^c
Experiment 1
wt VHSVmi	6, 0, 12	6	13.5*	8/9 (5)
rVHSVmi	0, 0, 12	4	19*	7/9 (3)
rVHSVmi-Gdk	12, 0, 6	6	14.5*	2/9 (0)
rVHSVmi-NVdk	0, 24, 6	10	11.6*	6/9 (3)
rVHSVmi-GNVdk	6, 0, 6	4	12.5*	4/9 (2)
wt VHSVdk	100	100	4.6*	nt
rVHSVdk	100, 100, 100	100	4.9 ± 0.20	nt
rVHSVdk-Gmi	100, 100, 100	100	5.2 ± 0.20	nt
rVHSVdk-NVmi	100, 100, 100	100	4.6 ± 0.28	nt
rVHSVdk-GNVmi	100, 100, 100	100	4.1 ± 0.15	nt
mock	0, 0	0	na	0/6
Experiment 2
wt VHSVmi	0	0	na	nt
rVHSVmi	0, 6, 6	4	8.5*	3/9 (3)
rVHSVmi-Gdk	0, 0	0	na	2/6 (1)
rVHSVmi-GNVLdk	0, 12, 0	0	14.5*	3/9 (3)
wt VHSVdk	100	100	3.5*	nt
rVHSVdk	100, 100, 95	98	5.0 ± 0.34	nt
rVHSVdk-Gmi	100, 100	100	5.1*	nt
rVHSVdk-GNVLmi	100, 100, 100	100	4.64 ± 0.27	nt
mock	0, 0, 0	0	na	0/9

^aWithin each experiment, all treatment groups were tested as triplicate subgroups of 20 juvenile rainbow trout, with the exception of mock challenge negative control treatments or wild type strain positive control treatment that were tested in some experiments as single or duplicate groups (as indicated in column 2) due to space limitations in the aquatic Biosafety Level 3 wetlab. Also, duplicate subgroups of 20 fish were used for the reciprocal G exchange chimeras in experiment 2 because this was a repeat test of this treatment group from experiment 1
^bMean day-to-death (MDD) for individual tanks was used to calculate the group average MDD and standard deviation (SD). *Asterisks denote MDD for groups that had mortality data from only 1 or 2 tanks, either due to tanks with no mortality or less than 3 tanks in the treatment. In these cases, no SD could be calculated. “na” means all tanks in the treatment group had no mortality
^cInfection status at 7 days post-challenge is shown for fish sampled from rVHSVmi-based viruses in experiments 1 and 2. For virus-positive fish, the number of fish in each group with viral loads greater than the challenge inoculum is shown in parentheses as an indication of the ability of the virus to replicate in vivo. The infectious viral loads determined by plaque assay are shown in Fig. 5

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