The Master Cleanse does NOT kill parasites, although some may be inadvertently swept out with the garbage. It is best to do a designated parasite cleanse pre or post-cleanse. I just finished up a month one myself in preparation for a juice fast in November...yee-haw~~!
I use a parasite cleanse from the Herbal Healer Academy, http://www.herbalhealer.com/parasites.html although there are many great ones out there so check into it online or at your local health food store.
Everyone has parasites generally and it is good body maintenance to do a parasite cleanse once or twice a year depending on your risk factors. I swim in lakes and streams and walk barefoot a lot, as well, garden, so pick up eggs in dirt and water-borne parasites are always a constant problem.