A parasitic infection in the colon usually is the result of contact with feces containing parasites. In some cases, food or water can be contaminated with feces, or the parasites may be present in the soil, according to the University of Maryland Medical Center. Many people can have an intestinal parasitic infection for years before symptoms develop. Once symptoms are present, they can range from mild to severe.
Diarrhea
One of the most common signs of an intestinal parasite is diarrhea. Some people also develop dysentery, which is loose stools that typically contain blood and mucus, according to the UMMC. Several types of common parasitic infections are known to cause diarrhea, including Entamoeba histolytica, Giardia lamblia and Cryptosporidium. Also, severe diarrhea is possible with an illness called Giardiasis, caused by the Giardia intestinalis parasite. Giardiasis is a common waterborne illness in the United States, according to the Centers for Disease Control and Prevention.
Gastrointestinal Distress
A parasitic infection in the colon can cause abdominal pain or tenderness, nausea, vomiting, bloating and gas. In the case of an infection caused by the Ascaris worm, stomach pain can be a sign of a severe infestation, according to the CDC. Ascaris worms typically live in the small intestine. In addition to stomach pain, severe infestations from Ascaris can lead to blockages of the intestines. These gastrointestinal symptoms can be similar to those of conditions such as Crohn's disease and gastric ulcers and should be evaluated by a doctor for diagnosis.
Itching
A pinworm infection, which is common in school-age children, can cause severe itching around the anus, especially at night, according to the National Institutes of Health. In girls, itching and irritation around the vaginal area are also possible.
Weight Loss
Another sign of a parasitic infection in the colon is unexplained weight loss, according to the UMMC. In some cases, weight loss occurs because of severe symptoms such as diarrhea. With some infections, though, the presence of the worms can cause weight loss.
Respiratory Problems
In rare cases, an Ascaris infection causes coughing and breathing difficulties. These symptoms develop when small, immature worms are able to work their way through the body to the lungs, according to the CDC. In some cases, the worms can be coughed up and expelled.
Presence of Worms in Stool
Another sign of intestinal parasites is the presence of worms in the stool. Because the parasites are living in the colon, they are passed from the body via the stool. Depending on the size of the worm, many people may not notice worms in the stool.
References
- University of Maryland Medical Center: Intestinal Parasites
- Centers for Disease Control and Prevention: Giardiasis
- Centers for Disease Control and Prevention: Ascaris
- National Institutes of Health MedLine Plus Medical Encyclopedia: Pinworms
- National Digestive Diseases Information Clearinghouse: Diarrhea
