Due to a high degree of similarity in lung physiology and distribution of sialic acids in respiratory tract tissues, the ferret model is frequently utilized to model the kinetics and severity of respiratory disease following administration of human and avian influenza viruses by the intranasal route [23, 25] . To determine if this homology extends to ocular tissue, we examined the composition of sialic acids on the ferret cornea, which represents a potential site of influenza virus replication following ocular inoculation. Staining of ferret corneal epithelial sheets with biotinylated lectins specific for a2-3 and a2-6 sialic acids revealed a predominance of a2-3-linked sialic acids with relatively weak expression of a2-6 sialic acids on the epithelial surface, an expression pattern similar to human corneal and conjunctival tissue (data not shown) [2, 20] .