Gastrointestinal Amebiasis

What is gastrointestinal amebiasis?

Gastrointestinal amebiasis is an inflammation of the colon caused by a parasite that enters the body through contaminated food or drinking water. This infection is rare in developed countries. It is more common in areas with poor sanitation or crowded living conditions.

The parasite can live in your intestine without causing symptoms, or you can have severe symptoms. Rarely, the parasite enters the liver or other organs through the blood.

How does it occur?

A parasite named Entamoeba histolytica causes this illness. You may become infected when you eat food or drink water contaminated with bowel movements that contain the parasite. You can also become infected when you eat food that has been handled by someone who has the parasite.

What are the symptoms?

The symptoms include:

• diarrhea, sometimes alternating with relatively normal bowel movements
• abdominal cramps or tenderness
• bowel movements streaked with blood or mucus
• sometimes fever
• vomiting or nausea (less common).

The time between the parasite's entry into your body and the appearance of the first symptoms can range from a few days to a few months.

How is it diagnosed?

Your health care provider will review your symptoms and examine you. You will have tests of your blood and a sample of your bowel movement.

Sometimes the diagnosis is difficult if you have had the symptoms for a long time. A test called a sigmoidoscopy may be done. This is a procedure in which the health care provider inserts a thin, flexible, lighted tube into your rectum to look for disease in your colon.

How is it treated?

Your health care provider will prescribe an antibiotic medicine. Your health care provider may also prescribe antidiarrheal medicine. Take all medicines exactly as your provider and pharmacist tell you. Take all of the medicine prescribed. If you stop taking the medicine when your symptoms are gone but before the parasite is gone from your body, your infection may come back.

If your symptoms are severe, you may need intravenous (IV) fluids until the diarrhea improves and you are out of danger of losing too much fluid (dehydration).

How long will the effects last?

The symptoms of diarrhea usually last 3 to 14 days, but they can last up to 4 weeks. Recurrences are possible.

How can I take care of myself?

Follow your health care provider's instructions.

If you have diarrhea, you may want to let your bowel rest for a few hours by drinking only clear liquids such as water, weak tea, bouillon, apple juice, or sports drinks or other oral rehydrating solutions. You may also drink soft drinks without caffeine (such as 7 UP) after letting them lose some of their carbonation (go flat). Make sure you drink often so you do not become dehydrated. Becoming dehydrated can be very dangerous, especially for children, older adults, and some people who have other medical problems. Suck on ice chips or Popsicles if you feel too nauseated to drink fluids.

It is OK to keep eating as long as it does not seem to worsen the diarrhea or stomach cramps. Foods that are easiest to digest are soft starchy foods, such as bananas, cooked cereal, rice, plain noodles, gelatin, eggs, toast or bread with jelly, and applesauce. Avoid milk products and caffeine for a few days. Return to your normal diet after 2 or 3 days, but for several days avoid fresh fruit (other than bananas), alcohol, greasy or fatty foods such as cheeseburgers or bacon, and highly seasoned or spicy foods. Avoid most fresh vegetables. Cooked carrots, potatoes, and squash are fine. If eating seems to worsen the diarrhea, let your bowel rest for a few hours by drinking just clear liquids.

If you have cramps or abdominal pain, it may help to put a hot water bottle or electric heating pad (set on low) on your abdomen.

Be cautious about taking nonprescription antidiarrheal medicines such as loperamide (Kaopectate or Imodium) or the prescription medicine Lomotil. These medicines can actually make the illness more severe, especially if the diarrhea is bloody. If you take one of these medicines, make sure you use only the dose recommended on the package. If you have chronic health problems, always check with your health care provider before you use any medicine for diarrhea.

If you keep having symptoms, the symptoms get worse, or you develop new symptoms, tell your health care provider.

How can I help prevent gastrointestinal amebiasis?

• Avoid unsanitary water supplies.
• When you are traveling, avoid food that is not cooked or peeled.
• Protect food from feces, flies, and contaminated water.
• When you are camping, boil water for 5 minutes or treat it with disinfectant tablets. (Adding chlorine to the water will not kill the parasite, but Globaline tablets and iodine will.)