What is giardiasis?

Giardiasis is the infection of the upper small intestine caused by the parasite Giardia lamblia.

How does it occur?

You may become infected:

• when you eat food or drink water that has been contaminated by human waste that contains Giardia lamblia

• through person-to-person contact among household members who have the infection

• if you stay in a day care center with children who are not toilet-trained

• through anal-oral sexual activity.

Those persons most susceptible to giardiasis are travelers, campers, children in day care centers, and male homosexuals.

What are the symptoms?

Often giardiasis does not have symptoms. Symptoms may not develop until 3 weeks after exposure to the parasite. When symptoms are present, they include:

• mild to severe diarrhea

• bowel movements that are bulky, greasy, frothy, and foul smelling

• cramps in the upper abdomen

• anorexia, nausea, or vomiting.

How is it diagnosed?

Your doctor will review your symptoms, if any, examine you, and order a lab analysis of a sample of your bowel movement.

How is it treated?

Your doctor will prescribe medication such as metronidazole, quinacrine hydrochloride, or furazolidone. Take all of the medication your doctor prescribes. If you stop taking your medication when your symptoms are gone but before the parasite is gone from your body, your infection may return.

How long will the effects last?

Symptoms of giardiasis may last for days or weeks.

How can I take care of myself?

If you have diarrhea, let your bowel rest by drinking only clear liquids such as water, juice, tea, bouillon, and oral rehydrating or electrolyte solutions. It is important to drink often so that you do not become dehydrated. Drink small amounts at frequent intervals if you feel too nauseated to drink fluids. Do not eat solid foods because they can cause cramps.

When your symptoms improve, eat small frequent meals or snacks. Do not fast. Good foods to eat during this time of recovery are light soups, gelatin, crackers, toast, rice, eggs, and applesauce.

Return to your normal diet gradually but avoid fresh fruit and vegetables, alcohol, and highly seasoned or spicy foods for several days. Avoid caffeine for a few days. You may also need to avoid milk and dairy products for a few days.

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.

If your symptoms persist or if you develop new symptoms, tell your doctor.

What can be done to prevent giardiasis?

• Wash your hands with soap and very warm water after going to the bathroom and before eating or preparing food.

• Avoid unsanitary water supplies.

• Avoid food and water that may be contaminated.

• Wash linens, towels, and diapers separately.

• Notify others who may have been exposed to the parasites (such as household members, sex partners, and day care contacts); they should be tested for the parasites.

• Avoid foods that can't be cooked or peeled, and protect food from feces, flies, and contaminated water.

• When camping, drink water only after it has been purified by boiling or with disinfectant tablets.