Just continue with the storyline. If it's your first time playing then go southeast until you find Rivet City ( The Aircraft Carrier), and find the science lab and talk to Dr. Li.
This is best left to a professional since treatment has to be thorough, dusts are required which float around all over the place and it will take quite a bit of chemical. If they are in mattress/box...
It depends on the active ingredient in the pesticide and how much of it a person consumes or absorbs. Some pesticides are highly toxic and can kill a full grown man if he gets as little as one ounce...