Rusfox
All your children can use
Clarkia . It can be added to juice or other drinks. To find out if they have
parasites you have to check their stool. Also, pinworms cause itching and feeling of discomfort in anus area. So you can ask your 10 year old about that.
Clarkia package contains quite good instruction how to use it with children of different age.
And, if I am not mistaking, you can use it yourself to while nursing.
Good luck!