Hoover everywhere! And damp dust bedrooms. (Sorry, worms make a lot of work) We have had worms 5 times in our house over the past 18 months.
I told the school my ds kept getting it, and they issued all kids with a leaflet about handwashing, and the school nurse came in to give a talk about not picking your nose, etc. And 200 children all went 'Urghhh!' , then calmly inserted their digits back in their nostrils.
Treat the whole family, and again 2 weeks later. And don't feel too skanky!