Fortunately, lice survive without a human host for only a day or two.
The nits take a week to ten days to hatch, though, so to play it safe, follow these guidelines:
1. Machine wash in hot water all the clothing and bed linens your baby came in contact with during the two days before treatment began. Put these items in the dryer on a high setting for at least 20 minutes.
2. Put all stuffed animals, comforters, and clothing that can't be washed in a sealed plastic bag for two weeks. An alternative suggested by the National Pediculosis Association is to put items that can tolerate the heat in a hot dryer for 30 minutes.