06.08.2014

Emerg Infect Dis vol. 20 (9) - September 2014

In December 2013, influenza associated with pandemic influenza A/H5N1 was reported in Canada in a patient who had traveled to China; the patient died in January 2014. In the absence of direct poultry contact by the patient, the possible route of transmission and infection, often influenced by receptor-binding properties of the virus, requires special attention. The investigators note two previously reported mutations, R189K and G221R, in the hemagglutinin protein in the virus isolated from the patient. They write that both mutations are found in the immediate receptor-binding pocket, and G225R has been known to change specificity of an H3N2 virus toward human erythrocytes. The authors note that the two receptor-binding pocket mutations were not seen in the most closely related Asian H5N1 sequences.
The researchers from Singapore and Canada suggested that G225R could incur a relative predicted increase in binding to the human-like receptors, the role of R193K is less clear with a slight predicted tendency of favoring avian-like receptors.