Figure 2

Characterization of PR8 and Color-flu systemic infection across zebrafish lines. (A) Decreased survival was greater in casper than AB or EK lines with 2 dpf systemic PR8 infection. PR8-infected zebrafish had a decreased survival rate compared to vehicle (HBSS) controls (p < 0.0001 for all lines). Casper zebrafish had a lower survival rate than EK (p = 0.0024) and AB (p = 0.0055) according to the log-rank Mantel–Cox test. (B) Decreased survival rates were observed in AB, EK, and casper with 3 dpf PR8 infection compared to controls (p < 0.0001 for all lines). No significant (ns) difference in survival rate was detected between PR8-infected AB, EK, and casper larvae. (C) Increased TCID₅₀ viral titer in 2 dpf PR8-infected AB, EK, and casper zebrafish at 24, 48, and 72 hpi compared to 0 hpi (adj. p-value < 0.001 for all comparisons except for AB 24 hpi (adj. p-value = 0.0006) and AB 96 hpi (adj. p-value = 0.0003)). (D) Increased TCID₅₀ viral titer in 3 dpf PR8-infected AB, EK, and casper zebrafish at 72 hpi compared to 0 hpi (adj. p-value = 0.0323, 0.0211, and 0.0452, respectively) and casper zebrafish at 48 hpi compared to 0 hpi (adj. p-value = 0.0063). (E) Decreased survival with 3 dpf mVenus-PR8-infected AB, EK, and casper zebrafish compared to HBSS controls (p < 0.0001 for all lines). As observed with PR8 infection, casper zebrafish had the lowest survival rate (67.7%), which was lower than that of AB (94.5%, p < 0.0001) and EK (85.5%, p < 0.0002). (F) mVenus-PR8-infected AB, EK, and casper zebrafish had an increased viral titer at 24 and 48 hpi compared to 0 hpi (adjusted p-values = 0.0012 and 0.0022, respectively, for AB; 0.0025 and 0.0027, respectively, for EK; and 0.0045 and 0.0066, respectively, for Venus-PR8). mVenus-PR8-infected AB and EK zebrafish had an increased viral titer at 72 hpi compared to 0 hpi (adjusted p-value = 0.0236, and 0.0281, respectively). Survival studies were conducted with four independent (n = 4) experiments and 50 larvae per sample group. TCID₅₀ assays were carried out with three independent (n = 3) experiments and 25 larvae per group for each time point. Not significant (ns), p > 0.05; * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001.