They are also spread throughout the world via international travel. Some parasites are larger than bacteria and viruses but they are usually so small that you cannot see them without a microscope. Others, such as worms, can grow quite large and can be seen with the eye. The parasites are often harmful. Any number of them can infect your gastrointestinal tract.
Most parasites produce similar symptoms.
According to Skye Weintraub, a naturopathic physician and author of The Parasite Menace, a parasitic infection could be manifested by any number of signs. These include constipation, diarrhea, gas and bloating, irritable bowel syndrome, joint and muscle aches and pains, anemia, allergies, skin conditions, nervousness, sleep disturbances, teeth grinding, and chronic fatigue. Many health practitioners believe not only that parasites result in symptoms such as those listed above but also that they may be responsible for a number of other health problems. It is easy to attribute feeling ill to other causes because parasitic infections look like lots of other conditions. I have seen other health problems disappear once the body has become parasite-free.