Giardiasis

What is giardiasis?

Giardiasis is an infection of the 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 or animal waste that contains Giardia lamblia
through person-to-person contact with household members who have the infection
if you work in a day care center with children who are not toilet-trained
through anal-oral sexual activity.

People most likely to have giardiasis are travelers, people who spend a lot of time outdoors, children and their caretakers in day care centers, and male homosexuals.

What are the symptoms?

Symptoms usually start 1 to 2 weeks after you are exposed to the parasite. Symptoms may include:

mild to severe diarrhea
bowel movements that are bulky, greasy, frothy, and foul smelling
cramps in the upper abdomen
loss of appetite
nausea or vomiting.

Some people with giardiasis do not have any symptoms.

How is it diagnosed?

Your health care provider will review your symptoms, examine you, and test one or more of your bowel movements.

How is it treated?

Your health care provider will prescribe an antibiotic medicine. Take all of the medicine your provider prescribes. If you stop taking the medicine when your symptoms are gone but before the parasite is gone from your body, the infection may return.

How long will the effects last?

Symptoms of giardiasis may last 2 to 6 weeks, or longer in some cases.

How can I take care of myself?

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 foods, such as bananas, cooked cereal, rice, plain noodles, gelatin, eggs, toast or bread with jelly, and applesauce. Return to your normal diet after 2 or 3 days, but avoid milk products and caffeine for a few days. For several days also avoid fresh fruit (other than bananas), alcohol, greasy or fatty foods such as cheeseburgers or bacon, and highly seasoned or spicy foods. And 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 covered hot water bottle or an 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.

Remember that giardiasis is very contagious.

If you keep having symptoms or your symptoms are getting worse, tell your health care provider.

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 handling food.
If you work in a day care center, wash your hands often, especially after you change diapers or help children use the toilet.
Avoid unclean water supplies.
Avoid food that may be contaminated.
Wash towels and diapers separately from other laundry.
Tell others who may have been exposed to the parasite (such as household members, sex partners, and day care contacts). They should be tested for the parasites.
Don't swim in public places while you have diarrhea.
In travels to other countries, avoid foods that can't be cooked or peeled.
Protect food from exposure to bowel movements, flies, and unclean water.
When you are outdoors, drink water only after it has been purified with boiling, proper filtration, or disinfectant tablets.
Avoid exposure to bowel movements during sexual activity.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File INF4547F.HTM Release 9.0/2006