Impetigo

[superfun]

So, a daycare boy was here all day, and had a blister on his mouth. I've never seen impetigo, and didn't think much of it. I thought it might be a cold sore.Anyways, his dad dropped him off and didn't say anything, his mom picked up and took him straight to a doctor. So he's got impetigo, and staying home tomorrow. He was playing mostly with the same kid all day today, and as I was talking to the other boys mom, the non infected boy grabbed infected boys cup and started drinking his water. So I'm thinking it's likely that boy will catch it right? I have never dealt with impetigo, and I'm hiding in my room with my kids, I won't let them into the rest of the house until I disinfect after they go to bed. Can I ask the other family to keep their kid home to see if he's going to catch it?
Or should I close tomorrow to try to keep this infection from spreading?