welcome to the site. I have a 5 yr old son and a 3 yr old son...my 3 yr old got the stomach virus for the first time this year, and my 5 yr old had it twice when he was 3...I think in kindergarden they understand more about keeping their hands clean. at least my son understands that we dont put our hands in our mouths etc...it is important for him to go to school. i home schooled part of this year and decided to put him back into preschool bc he missed being with his friends...good luck...it will all work out!