Dr. Hans-Dieter Klenk (University of Marburg)

On adaptation of swineflu (H1N1) to humans:

"Several studies have identified a number of mutants in the polymerase when an avian influenza virus is transmitted to a mammalian host. Among these adaptive mutations, which not only modulate host range but also pathogenicity, are the following: PB2 E627K, PB2 D701N, PB2 S714R,  PB1 L13P, PA K615R. A/California/04/2009 (H1N1) has PB2 with E, D, S and PA with K at these positions, respectively, whereas PB1 has P at position 13. These observations are consistent with the concept that PB2 and PA of this virus are presumably of avian origin.

They also suggest that the virus has the potential to further adapt to humans and to change pathogenicity."

How influenza virus inhibits early antiviral responses: from Dr. Vincent Racaniello's blog (June 4, 2009).

WHO lists warning signs for severe H1N1 disease