The key to getting rid of lice is to nit pick. That is the key to finding out if your kids have it too. Check thier heads, use a magnafiying glass if you need it, and if you see anyhing that looks like brown sand stuck very close to the scalp, get a metal lice comb, treat with one of the shampoos for lice, and then get a product from Rid that is a gel that helps you comb out the eggs, and nits, and live bugs if you have any. It is necessary to wash bed linens and towles, and to check car seats and places that they rest their heads, but don't go crazy there. Spend your time where the lice like to be...on your child's head. Even a live bug cannot survive with out a blood meal for more than 24 hours off a head...so if one got loose in your childs cubby, for intance, they would have to pick up the item that had the live bug on in, and place it on their heads...kind of unlikely, espeicially if the hair with the bug on it fell on the floor, or some where else.
It can take hours to pick through one head, but it is the only way to get rid of them. If you see small white specks on the hair a half inch from the sclap that you have to scrape off with a finger nail, that is a nit, and that was an egg that already hatched. That is from a prior infestation, and you will probably find eggs and bugs if you look more closely. The bugs like to hide behind ears, and at the base of the neck line, so start there. If you have them, once you start combing the gel out (it is clear, and really, really helps-and that has no chemicals in it, it just helps you to lubricate the hair so that the nits and eggs come out more easily) you will seen hundreds of brown specks in the gel as you comb it out. You will need to comb and pick every day for a while, until you are sure it is gone.
Chances are, once they found the case, your child has already been exposed and is treated, so you have no reason to keep your child home, unless they have it, or it becomes a constant issue, meaning that one family is not doing what needs to be done to get rid of them, which is more common than you think. It is a big pain, and it takes hours of work. Put a movie in, and comb...
M.