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~~!
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.