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Giardia Infection (Giardiasis)



  • Giardiasis is an infection caused by a parasite called Giardia that can cause abdominal pain and diarrhea.
  • Your child’s healthcare provider may prescribe medicine that will kill the parasite, if your child has symptoms.
  • Have your child take all medicines exactly as prescribed. Make sure you know when your child should come back for a checkup.


What is giardiasis?

Giardiasis is an infection caused by a parasite called Giardia.

What is the cause?

The parasite lives in the animal or human intestine. Bowel movements can spread the parasite to soil, water, or food. Vegetables or fruit can be contaminated by contact with this soil or water. Contaminated food usually looks and smells normal.

Your child may get infected if your child:

  • Swallows water from a well, lake, stream, or city water that has not been treated to kill germs
  • Has contact with an infected animal
  • Drinks contaminated water or eats contaminated food
  • Eats food that has been handled by someone who is infected
  • Has contact with bowel movement from an infected person by touching towels or bathroom fixtures the person has used or through sexual contact
  • Spends time at a day care center where children are infected and in diapers or not toilet-trained

What are the symptoms?

Symptoms usually start 1 to 2 weeks after exposure to the parasite. Symptoms may include:

  • Mild to severe diarrhea
  • Bowel movements that are bulky, greasy, frothy, and foul smelling
  • Cramps or tenderness in your belly
  • Loss of appetite
  • Nausea or vomiting
  • Weight loss

Sometimes it doesn’t cause any symptoms.

How is it diagnosed?

Your healthcare provider will ask about your child’s symptoms, activities, and medical history and examine your child. Be sure to tell your provider if your child has been hiking or camping, has been swimming in a lake, pond, or river, or has traveled outside the country recently. A sample of bowel movement will be tested. You may be asked to submit several bowel movement samples collected from your child over several days.

How is it treated?

Your child’s healthcare provider may prescribe medicine that will kill the parasite. Your child may not need medicine if your child does not have symptoms. However, treatment can help keep your child from spreading the parasite to others, for example, in a day care center. Talk to your healthcare provider about this. Also talk to your child’s provider if your child has side effects from the medicine.

Symptoms of giardiasis may last 2 to 6 weeks. Sometimes they last longer.

How can I take care of my child?

Follow your healthcare provider’s instructions. Make sure that your child takes medicine exactly as it is prescribed. If your child stops taking the medicine too soon, the infection may come back. If you have side effects from your medicine, talk to your provider.

Here are some things your child can do to feel better:

  • Rest the stomach and bowel by having your child not eat anything and by drinking clear liquids only. Clear liquids include water, weak tea, fruit juice mixed half and half with water, Jell-O, or clear drinks without caffeine such as a lemon-lime soft drink. Stir the soft drink until the bubbles are gone. Avoid liquids that are acidic such as orange juice, or caffeinated such as coffee.
  • If your child has severe diarrhea, your child’s body can lose too much fluid and get dehydrated. Dehydration can be dangerous, especially for children. Your child may also be losing minerals that the body needs to keep working normally. Your healthcare provider may recommend an oral rehydration solution (ORS), which is a drink that replaces fluids and minerals. You can buy these products at drug and grocery stores.
  • Your child may eat soft, plain foods. Good choices are soda crackers, toast, plain pasta, rice, cooked cereal, applesauce, and bananas. Your child should eat slowly and avoid foods that are hard to digest or may irritate the stomach including foods with acid such as tomatoes or oranges, spicy or fatty food, meats, and raw vegetables. Your child may be able to go back to a normal diet in a few days.
  • Your child may not tolerate dairy products until digestion returns to normal. If this happens, have your child avoid milk, cheese, yogurt, and other dairy products for several weeks after treatment.
  • Don’t give your child aspirin, ibuprofen, or other nonsteroidal anti-inflammatory drugs (NSAIDS) without checking first with your healthcare provider. NSAIDs, such as ibuprofen, naproxen, and aspirin, may cause stomach bleeding and other problems. Read the label and give as directed. Children under age 18 should never be given aspirin due to the risk of Reye’s syndrome, which is a serious liver condition.

Ask your child’s healthcare provider:

  • How and when you will get your child’s test results
  • How long it will take to recover
  • If there are activities your child should avoid and when your child can return to normal activities
  • How to take care of your child at home
  • What symptoms or problems you should watch for and what to do if your child has them

Make sure you know if or when your child should come back for a checkup. Keep all appointments for provider visits or tests.

How can I help prevent giardiasis?

These steps can help prevent giardiasis and food poisoning:

  • When you are camping or hiking, drink water only after it has been purified with boiling, proper filtration, or disinfectant tablets (available at most sporting or camping stores).
  • Wash your hands and clean any dishes or utensils before you prepare, cook, serve, or eat food. Keep kitchen counters and other food preparation surfaces clean. Replace used dishcloths and kitchen towels with clean ones often.
  • Cover any sore or cut on your hands before preparing food. Use rubber gloves or cover the sore with a clean bandage.
  • Rinse fresh vegetables and fruits before you eat or cook them.
  • Thaw frozen meats in the refrigerator or a microwave. Do not let meat stand at room temperature.
  • Cook food thoroughly, especially meat, poultry, and leftovers. Pork should be heated to an internal temperature of at least 160°F (71°C). For whole chickens and turkeys, a temperature of 180°F (82°C) is recommended for thigh meat and 170°F (77°C) for breast meat.
  • Keep juices from raw meat, poultry, and seafood away from other foods.
  • Refrigerate any food you will not be eating right away.
  • Wash your hands after you go to the bathroom or touch animals.
  • If you take care of young children, wash your hands often and dispose of diapers carefully so that bacteria can't spread to other surfaces or people.
  • Tell others who may have been exposed to the parasite, such as household members, sex partners, and day care contacts, that they may need to be tested for the parasite.
  • Practice safe sex. Use latex or polyurethane condoms the right way during foreplay and every time you have vaginal, oral, or anal sex.
  • Don't swim in public places while you have diarrhea.
  • When you travel to places where contamination is more likely, eat only hot, freshly cooked food. Don't eat raw vegetables or unpeeled fruit. Drink only bottled water and liquids. Avoid tap water and ice or boil water before drinking.
Developed by Change Healthcare.
Pediatric Advisor 2022.1 published by Change Healthcare.
Last modified: 2021-09-06
Last reviewed: 2019-08-22
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2022 Change Healthcare LLC and/or one of its subsidiaries
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