How to prevent others from getting infected with parasites when I am living with them?

I live with my mom, dad and sister. I really really don't want them to catch the parasites/worms. How do I prevent that? we all use the same toilet and bathtub... please please please could anyone shed insight upon this? i think it might be Ascaris eggs, because i had coughing symptoms in the beginning. A few weeks ago i heard my sister cough out of the blue and i got soo scared. please, how to prevent others from catching while I am fighting this battle?