If someone had head lice at my child's school, but they aren't itching, should I be worried?

You need to get rid of all the nits or they will rehatch. First block is the tree oil. Wash your hair and body with it. Test it first to be sure your not allergic . Crab. Bed bugs are another horrible insects. In apartments these things migrate through spaces in the walls. It is a pain but all pillows, clothing , and bedding needs to be heat treated and then an insect dog needs to be brought on to be sure the infestation is done. Your friend needs to realize they are carriers and everything they own is possible contamination . So moving only spreads the issue.

you should google that question - there are many answers, here is one.:
Head lice is manly found/picked up by little kids in sand but you can get it from grass with sand in it and trees with lots of birds might have some lice on the nest but as far as I know they are both safe areas as long as no sand or animals are contributing. Animals are really the big deal though because the lice has to have something to live off of and the sand is so bad because animals lay there for warmth and cats like to ***** matter - there. If you have a backyard with minimal animal contact there is less of a lice chance.

Normal wash will do it .

It is absolutely possible to get lice in a hospital, or for that matter, anywhere else where people share common items. For example: I'm a school teacher. Used to be that our kids came in and hung their coats from a series of hooks. After we cleaned up the infestation, we then put up those trash bags with the tie-strip on them - everybody's coat goes in THEIR bag (write name on them) and the =bagged coat hats, etc= got hung on the hook. Aside from the stray case that would occur once in a while (usually among siblings or close playmates) the rate of occurrence dropped to nearly none at all. SO... if you're at a hospital where you hand you lab coat or other personal beloongings where others do, you're at risk. Take one of those nice kitchen garbage bags (the white ones are nice) write your name on it, stuff all your stuff in it, and hand it on the hook. Side beneift, you'll be less likely to lose any of your stuff to theft, as someone would have to root around in the bag.

PLEASE NOTE: I'm not a doctor or medical professional, this is drawn purely from experience of 30 years of being around those who CAN carry lice easily.