Symptoms of Human Intestinal Parasites

Human intestinal parasites are those that host themselves in the intestinal tract of the human body. According to the University of Maryland Medical Center, there are two types of intestinal parasites. Helminths, such as tapeworms, pinworms and roundworms, are worm-like and large enough to be visualized without the use of special equipment. Protozoa, the other type, consist of only one cell. The symptoms of intestinal parasites range from mild to severe.

Bowel Changes

Changes in the bowels are common in those with intestinal parasites. Parasites survive by living in the intestines and taking nutrients from food ingested by the host. The intestines can be heavily populated by these parasites, making it difficult for waste to travel efficiently through the intestines which commonly causes constipation. Depending on the type of parasite, diarrhea or loose stools may occur.

Change in Appetite

An individual may experience changes in appetite as a result of parasites. Usually there is a noticed increase in appetite, because the parasite is taking nutrients from the host's body. Some individuals may even experience weight loss with the increase in appetite. In contrast, some may experience a decrease in appetite. This may occur in conjunction with nausea and vomiting as the body attempts to fight or rid itself of the parasite.


Abdominal pain or tenderness can result from intestinal inflammation caused by the parasites. As the parasites attach to the lining of the intestines, the intestinal walls may become inflamed as a means of defense against the foreign organism. Pain may be located elsewhere in the body if the parasites have traveled beyond the intestines to other parts of the body. This usually indicates a long-time parasitic presence in the body.

Additional Signs

Additional signs of intestinal parasites include flu-like symptoms, increased bloating and gas and passing of worms in stool. Flu-like symptoms occur as the body's immune system attempts to attack the parasite. An individual may experience specific symptoms, such as body aches, fever and headache. Rarely, individuals may visualize parasites in stools. This generally occurs in individuals who have been infected with intestinal parasites for a prolonged period.

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