Seasonal and pandemic human influenza viruses attach better to human upper respiratory tract epithelium than avian influenza viruses.
van Riel D, den Bakker MA, Leijten LM, Chutinimitkul S, Munster VJ, de Wit E, Rimmelzwaan GF, Fouchier RA, Osterhaus AD, Kuiken T. Am J Pathol. 2010 Apr; 176(4):1614-8. Epub 2010 Feb 18.