Before you go crazy and clean and disinfect EVERYTHING, keep in mind you only need to wash whatever has been in contact with the child's head in the last 48 hours. Lice and nits don't survive very long when away from your scalp. I have personal experience with lice, my son got it from school, and although a little gross at first, you get used to it. Make sure you notify all parents that their child has been in contact with lice and have all parents check their kids. If a lice or nits are found on a child, then they need to be treated ( with lice shampoo) and may return to daycare immediately after the shampoo (at least that's how the schools do it). They need to be retreated in 7-10 days. HOWEVER lice shampoos are only somewhat effective and shouldn't be relied upon 100%...I found the best way to get rid of them for good was to get a lice comb and remove the nits manually before they hatched.

On a side note though, I would not be impressed at having to wait three hours for someone to pick up. I have it in my handbook that parents need to pick up within the hour otherwise I call emergency contacts. Last day though so whatever I guess. Good luck