13.01.2007

In a new paper in Nature Medicine by Nicholls JM, Chan MC, Chan WY, et al. it appears that both H5N1 and H3N2 bind and replicate quite well to tissues in the upper respiratory tract.
Poor human-to-human transmission of influenza A H5N1 virus has been attributed to the paucity of putative sialic acid α2-3 virus receptors in the epithelium of the human upper respiratory tract, and thus to the presumed inability of the virus to replicate efficiently at this site. These researchers now demonstrate that ex vivo cultures of human nasopharyngeal, adenoid and tonsillar tissues can be infected with H5N1 viruses in spite of an apparent lack of these receptors (Nature Medicine: published online 7 January 2007).