it is currently affecting -2,0 0,-1 and 0,-3
only entities that are present when you enter an affected area are invisible to you (not just wild pokémon,but other trainers, their and your pokémon, any NPCs etc), and anything that appears while you are still inside will be visible. leaving the affected area and re-entering resets this (so something that did spawn while you were there that you could see will become invisible if you leave and return).
it is annoying, yes, but as slayer notes, the invisible pokémon can be fainted, and traversing the affected tiles is very possible by using right-click to send and keep one of your pokémon ahead of you.