RT-qPCR analysis for PRV in blood (A) and white skeletal muscle (B). Fish groups with melanised, red or no changes are coloured brown, red, and grey, respectively. (A) Detection in blood presented by box plot with whiskers indicating max/min of the Ct-values from Group A (n = 25), B (n = 35), E (n = 20), F (n = 42), G (n = 43) and H (n = 10). The percent of fish in each group with melanised focal changes are displayed. (B) Samples from red or melanised focal changes (+) and non-affected areas (−) from the same individual. Box plot and whiskers showing max/min of the Ct-values from Group C with red focal changes (n = 6), and from Groups A (n = 9) and E (n = 14) with melanised focal changes. Only non-affected tissue (−) could be tested from groups without changes; i.e. Groups F (n = 6) and G (n = 6). Analyses were performed using Wilcoxon matched pairs signed rank test. *p < 0.05.