Lake Trout (Salvelinus namaycush) Naturally Infected with Salmovirus salmonidallo3 (SalHV-3; Family Alloherpesviridae) Continue to Harbor the Virus for Nearly a Decade

<i>Salmovirus salmonidallo3</i> (SalHV-3) causes Epizootic Epitheliotropic Disease (EED), which has resulted in the death of millions of lake trout (<i>Salvelinus namaycush</i>) over the past 40 years. Although advancements in understanding this virus's pathogenicity and control strategies have been made, the duration and effects of chronic SalHV-3 infections remain unknown. This study focused on lake trout that survived a natural outbreak of EED in 2012 and were maintained under quarantine conditions until 2021. Following exposure to either repeated or intermittent handling stress designed to mimic typical hatchery practices, SalHV-3 was detected (via a SalHV-3-specific quantitative PCR assay) in multiple tissues from multiple fish. Non-lethally collected tissues revealed the highest prevalence and virus loads in the fin and mucus. SalHV-3 was detected in these tissues throughout the study period (49 days, 8 sampling events), with some fish having detectible virus on each study day and others only intermittently (<i>n</i> = 1-7 sampling days). Tissues collected lethally yielded SalHV-3 detections in multiple nervous tissues, as well as in the cornea of several fish. Experiments to evaluate virus shedding revealed that SalHV-3 was intermittently detectable in fish holding water. Collectively, results indicate that lake trout can remain SalHV-3 infected for nearly a decade and intermittently shed the virus, constituting a threat to hatchery-based lake trout conservation efforts in the Great Lakes basin.