A collaborative report (by Dutch and Chinese contributor) published yesterday from Eurosurveillance shows that 5/7 H7N9 strains from humans, birds and the environment have an amino acid change in the HA gene called Q226L (the normal" glutamine [Q] found at amino acid position 226 has "mutated" to a Leucine[L]).
In the past, this change has been associated with binding of influenzavirus to a receptor molecule called alpha(2,6,)-linked sialic acid, which is found in the human upper respiratory tract.
A virus that is happy to replicate in the upper airways, one of the first ports of call for inspired virus-laded droplets, is going to have a good ability to spread by the aerosol route. [I include the eyes in here - but they may considered anatomically separate and the true first point of contact with virus-laden aerosols as they are probably open more than the mouth.
