An actual nightmare before Christmas. How do I handle this?

I’m working on accepting things that are out of my control and wow here’s a test. I got a message from my daughter’s daycare on Sunday saying there had been an exposure of hand foot and mouth disease and a couple kids had developed symptoms. They let us know they’ll be doing extra sanitizing while the daycare is closed this week. I didn’t think much of it and went on about the day.

Fast forward to last night my husband comes in from doing bedtime and says our daughter has bumps on her palms and around her mouth. My heart sank. Dammit.

We have several family members coming to town for Christmas to stay at our house. My daughter and her cousins had a sleepover planned. This is the first year at her age that she really gets Christmas and has been looking forward to it as most kids are.

We’ve been decorating the house, counting down, setting up, secret Santa planned, obvious gift exchange and dinner planned.

Now we just cancel? My grandmother is in her 80s my cousins have babies and infants and there’s a ton of kids and adults in between. I would feel so guilty if my house was a super spreader event. So I’m off to make alll those phone calls.

I’m just concerned about my baby, I don’t want her to feel left out, or disappointed, or sad. Have do you explain this to a child? What’s the play for the next couple of days now that everything we’ve been planning and waiting for has changed?

Also, I’m in my 30s I don’t remember HFM disease being a thing when I was a little. Chicken pox sure, but I don’t recall classmates or friends getting this.