Abbreviation for Viral Terminal Organism. A Viral Terminal Organism is a virus that enters your body whenever you voluntarily leave work before the end of your regularly scheduled shift. It is transmitted by IEX, which despite claiming to be a "nice company", isn't so nice afterall. Basically, you leave work early, you die. Just like AIDS. VTO is thus another way to force you to stay, working in slave-like conditions, all the while corporate jabronies deepen their pockets off of your productivity. Also of note, it is the opposite of taking extended hours, which of course results in cold hard cash.
"Man, don't even think of leaving work early today. You will contract the VTO, and die a horrible death. That **** is dangerous."