Just wanted to make sure I wasn't talking out of my behind;
It wasn’t until early 2074 when Aztechnology CEO Flavia de la Rosa met with President Silva, informing the president that one of the weapons projects, Blue-227, was viable.
On October 3, 2074 at approximately 1350 Zulu, after several other units all over Aztlan were put on alert and mobilized, Aztlan Special Forces augmented by several specialist units (that’s military jargon for shadowrunners and mercenaries) began phase one of the plan and assaulted Sirrurg’s base head-on.
FastJack, Riser, and their team went into the Albuquerque facility on December 3rd, 2072.
My money is still on the Shedim and/or Winternight's actions.
[EDIT]
Actually, now that I think about it, maybe we'll get to know a little more when the third (and final?) book about Thomas McCallister is released. After all, there's some pertinent information in the second one about Infected showing signs of something changing in them.