The co-infection challenge trial. The timeline above indicates weeks post PRV shedder introduction (WPC-PRV). Blue down arrow indicates transfer to sea water (SW). Yellow down arrow and yellow up arrow indicates introduction and removal, respectively, of PRV shedder fish. Red down arrow indicates introduction of SAV shedders. “Naïve fish 1” indicate the experimental fish before virus challenge, “Naïve fish 2” indicate fish dedicated to be SAV shedders and SAV controls at 4 WPC-PRV and “Naïve fish 3” indicate fish dedicated to be SAV shedders at 10 WPC-PRV. Blue box named “PRV cohabitation” indicates cohabitant fish exposed to 50% PRV shedders from 0 to 4 WPC-PRV. Blue box named “PRV” indicates PRV cohabitants from 4 to 10 WPC-PRV without PRV shedders. Boxes indicating a 6 week period of exposure to 20% SAV shedders are colored red (SAV only) and green (PRV-SAV). Co-infection induced at 4 WPC-PRV and 10 WPC-PRV is denoted PRV-SAV-early and PRV-SAV-late, respectively.