Preposed "critical step" in avian flu pandemic

Reports are coming out on the research at The Scripps Institute, the Centers for Disease Control, and the Armed Forces Institute of Pathology which is attempting to elucidate the mutations required to transform the avian flu into pathogen that can accomplish human-to-human transmission.

By looking at hemagglutinin (the "H" in H5N1), a molecule expressed on the surface of the virus which allows binding to host cells, they are trying to determine which mutated form will make it a human pathogen.

They compared a strain of the avian flu virus which killed a Vietnamese boy, to one obtained from an infected duck from Singapore. The Vietnamese H5N1 strain appeared very similar that the one responsible for the pandemic of 1918, which may have killed up to 100 million people worldwide.

These researchers believe that they have located a structure which may indicate the virus's ability to readily infect humans in an airborne manner. The bird alpha 2-3 receptor may need to mutate to the human alpha 2-6 to confer this infectivity. They further state that it may take as few as two mutations to create strain capable of producing a human pandemic.

Their glycan microarray test could be used in the field to test for this receptor specificity, and thus allow monitoring mutations as the avian flu virus spreads across the continents.