I’d assume that all these specialists are probably either dead, dead with a hunger for your flesh or got evacuated/relocated.
However, since there are books that can teach you how to mix, build and use military grade explosives, I’d also expect to find some books or at least some notes hinting the existance of parasites and some of the common symptoms to the player or the character.
Side note: You could have reused (rephrased and recategorized) your previous topic to keep the things from having to get discussed here again. Also, personally I wouldn’t declare this as a “bug” for The Garage but rather a feature request (“The Drawing Board” may suit it more?), but that’s just my opinion.