Some researchers state that the waste material produced by flukes is extremely carcinogenic and contributes to the formation of cancer. The waste material from just one tapeworm can make someone ill. Microscopic parasites can cause arthritis-like symptoms. It is impossible to avoid all situations that could lead to parasitic infection. Drink clean, pure water.
Distilled water is best to drink.
However, there are many purification systems that produce clean water. Reverse osmosis, carbon block and other types of systems can ensure that the water you drink is free from possible contamination. Chlorination does not kill all parasites. If you live in the city, buy a filter or purified water from a store. Always wash your produce, especially vegetables.