Wildfire is a level four quarantine directive at Stargate Command. When activated no one is allowed to enter or leave Stargate Command and the auto self-destruct may or may not be initiated. A Wildfire has been used at least once when Major General George S. Hammond activated it, using authorization Code Red dash Beta, when the alien orb organisms overran Colonel Jack O'Neill and the Gate room. (SG1: "Message in a Bottle").
Considering the name and the fact that the wildfire directive is for quarantine in the event of threat by a extraterrestrial microorganism, it is likely a reference to the Wildfire Project from the science fiction novel The Andromeda Strain, a project created for the same purpose of handling threats by extraterrestrial microorganisms. The strain in the book feeds on energy like the organism from P5C-353, and the auto-destruct in the book almost fed the organism in the same way the SGC's auto-destruct would have; being activated upon breakdown of containment and having to be shut down due to the organism thriving on the energy.