Macroscopic signs of ocular disease in ferrets were not observed during the course of infection with any virus tested, similar to prior observations in mouse and rabbit models following deposition of influenza virus on the corneal surface [20, 39] . A previous study in ferrets reported mild conjunctival inflammation following i.o. inoculation with an H7N3 virus, however this may be attributable to strain-specific differences or the use of younger (3-5 month old) ferrets [24] . Despite the absence of visible ocular complications, virus was consistently detected in CW samples from ferrets inoculated by the intranasal or ocular route (Table 2, Figure 2 ). Levels of viral M1 RNA generally correlated with the magnitude of virus isolation, and were a more sensitive detection method compared with virus isolation in CW samples, similar to that observed in human eye swabs (Table 4, Figure 2 ) [40] . The presence of virus in RS samples following both i.n. and i.o. inoculation with influenza virus has been previously reported and likely originates from virus swallowed during inoculation [24, 32, 41] , as indicated by deposition of virus in the esophagus following initial virus inoculation by both inoculation routes (Table 3, Figure 3 ).