Human parasites are everywhere, and they are very easy to contract from our food, water, animals, even from each other. Some parasites (eg. Pinworms) can even be transmitted through the air. Therefore, for prevention, it's recommend that a complete cleansing be performed twice a year.
A parasite is an organism which lives off, and generally within, a host body, such as our own body, or other living organisms, like plants and animals. They live off the "life" of another body, feeding on the nutrients, cells and organs of the host, reproducing by depositing thousands of eggs, or simply replicating by cell division, within the host's tissues and cells.
Parasites are often mobile, "grazing" in one area of the body after another, eating the host's cells directly or draining the best of the nutrients directly from the host's tissues, all while secreting their fecal wastes throughout the host's body, leaving their poisonous toxic sludge (like ammonia) behind, further taxing the host system's abilities even more gravely. Parasites likely infect everyone. It's estimated that as many as 85% of the world's population is so inflicted. In fact, it's highly likely that you are infected by one or more of over 1000 known parasites which can live in your body at any one time.
Most stomach aches and colitis could have a parasite involvement. Liver damage and liver trouble can often be caused by worms. Sometimes a colony of worms will crawl up in the gall bladder and give you trouble. This can be the trouble with overweight people. The worms are being well fed. The body is only getting the water and the calories but a fraction of the nutrients.
Three of the most common parasitic infections are:- Giardia Lamblia which BioTech Healing often identify, Blastocystis Homins (chronic fatigue, arthritis & diarrhoea) & Dientamoeba Fragilis (ingested pinworms from contaminated food causing diarrhoea & blood in the stool.)
Tiredness, lack of energy, minor ailments to full blown infections - look here for more definitive information:
http://www.ksu.edu/parasitology/625tutorials/index.html
http://www.dpd.cdc.gov/dpdx/HTML/Image_Library.htm
http://www.niaid.nih.gov/factsheets/roundwor.htm
Most parasitic infections come from our food and water sources but can also be transmitted by human or animal contact. Simply petting and grooming our pets can facilitate infection, the parasites' eggs passing from their fur to our hands, nose and mouth. Some parasites (e.g. pinworms) can even be transmitted through the air and are in the dust we breath. It's likely, therefore, that those who live in the same household will all have the same parasitic infections, whether they are currently symptomatic or not.