Humans may contract intestinal parasites through contact with infected feces in water, food or soil. According to the University of Maryland Medical Center, mainly two types affect humans: helminths and protozoa. Tapeworms, pinworms and roundworms make up the common helminths, and the most common parasitic protozoa include Giardia and Cryptosporidium. The difference between the two revolves around their ability to multiply inside the body: helminths cannot, while protozoa can. These intestinal parasites cause a variety of symptoms in the human body.
Giardiasis
Giardiasis, a digestive tract illness that is the leading cause of diarrhea, affects between 1 percent and 20 percent of the U.S. population, according to KidsHealth.org. A parasite called Giardia lamblia attaches to the lining of the small intestines, preventing the absorption of fats and carbohydrates from digested foods. Contaminated water serves as the vehicle through which Giardia lamblia transmits to humans. It may survive chlorine treatments to community water supplies and thrive for two months or more in cold water. Treatment for giardiasis includes medication to kill the parasite.
Swimmer's Itch
Swimmer's itch presents as a skin rash. This condition, also called cercarial dermatitis, results from parasites released by infected snails into both freshwater and saltwater. The parasite burrows into the skin of humans in the water, causing a rash, small blisters and red pimples. The Centers for Disease Control and Prevention states that the larvae die in the host on their own, making treatment to kill the parasite unnecessary. The rash discomfort may require treatment, however. Physicians may prescribe steroid cream, or sufferers can utilize treatments like cool compresses, oatmeal baths or anti-itch medicines.
Anemia
Anemia caused by blood loss may occur from intestinal parasite infection, according to the CDC. Hookworms, for instance, can bring about these conditions if the sufferer is heavily infected. Hookworm, a parasite that embeds in the skin in larval form, attaches to the small intestines after developing into a half-inch long worm. While more common in tropical and subtropical climates, these infections can occur in the United States. Treatments include medications to kill the parasite, as well as supplements to help clear up the anemia.
