Strangely, the Nowhere Triangle Infected Zone is located in Area 51.5. Probably becuase their names are both spin-offs of other things. The Bermuda Triangle, and Area 51. Also, when you have a mission in Area 51.5/Nowhere Triangle, the mission always says it is in Nowhere, which doesn't have an infected zone.
Fusion Gwen's Secret lair
Fusion Stickybeard's Secret lair