I note this quote in the link you provided:
Dr. Clark claims that much of our bad health comes from chemicals and toxins that we are subjected to on a daily basis. Among these chemicals are mercury from amalgam dental fillings and isopropyl alcohol from cleaning products and many others. She also claims that in addition to these chemicals that there are many parasites that invade our bodies and cause illness.
In her later years, did Dr. Clark move away from her contention that parasites/flukes were the cause of ALL cancer and disease? If so , good for her. Clearly, while parasites can cause and contribute to a great deal of disease, they are not the sole cause of cancer or other diseases by a long shot.
One reason I am keenly interested in this answer is that I know a young lady who quotes Clark and insists that all cancers are parasite - and believes that all she has to do to cure her own cancer is get rid of parasites.