Nature  
Volume 486 Number 7404 pp439-564  28 June 2012
http://www.nature.com/nature/current_issue.html

News Feature
Influenza: Five questions on H5N1
Scientists now know that the deadly bird flu virus is capable of causing a human pandemic. That makes tackling the remaining unknowns all the more urgent.
Ed Yong
21 June 2012  [Free full text]