“…Although the primary mode of PRV transmission is almost certainly horizontal, it is probable, given the systemic nature of PRV infections, that PRV contamination of sexual fluids permits the potential for egg‐associated vertical transmission from parent to offspring. Fish in freshwater hatcheries in North America, Europe and Japan have become infected presumably via this method (Kumagai et al., 2019; Løvoll et al., 2012; Polinski et al., 2019); however, a study following a population of Norwegian Atlantic Salmon brood fish and progeny from 2008 to 2011 found that PRV was not isolated in or on eggs collected from infected brood fish following a Buffodine ® disinfection treatment (Wiik‐Nielsen et al., 2012). Similarly, neither PRV‐1 in juvenile Atlantic Salmon from British Columbia nor PRV‐3 in Rainbow Trout from Denmark could be detected after being reared from iodine disinfected eggs even though the brood fish supplying the respective hatchery facilities carried high systemic RNA loads of PRV (M. Polinski, K. Garver and N. Vendramin, unpublished data).…”