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.

You may get infected if you put anything in your mouth that contains the parasite. For example:

• You eat contaminated food.
• You eat food that has been handled by someone who is infected.
• You swallow water from a well, lake, stream, or city water that has not been treated to kill germs.
• You have contact with an infected animal.
• You have contact with bowel movement from an infected person by touching towels or bathroom fixtures they have used or through sexual contact.

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 symptoms, activities, and medical history and examine you. You will have a test of a sample of bowel movement.

How is it treated?

Your healthcare provider may prescribe medicine that will kill the parasite. You may not need medicine if you are not having symptoms. However, treatment can help keep you from spreading the parasite to others. Talk to your provider about this. Also talk to your provider if you have side effects from your medicine.

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

How can I take care of myself?

Follow your healthcare provider’s instructions. Take all medicines exactly as prescribed. If you stop taking the medicine too soon, your infection may come back. If you have side effects from your medicine, talk to your provider.

Here are some things you can do to feel better:

• Rest your stomach and bowel but make sure that you keep getting fluids. You can do this by not eating 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 soft drinks without caffeine (like lemon-lime soda). Stir soda until the bubbles are gone (the bubbles can make vomiting worse). Avoid liquids that are acidic, like orange juice, or caffeinated, like coffee. If you have diarrhea, don’t drink milk.
• If you have severe diarrhea, your body can lose too much fluid and you can get dehydrated. Dehydration can be very dangerous, especially for children and older adults. You may also be losing minerals that your body needs to keep working normally. Your healthcare provider may recommend an oral rehydration solution, which is a drink that replaces fluids and minerals.
• You may eat soft, plain foods. Good choices are soda crackers, toast, plain noodles, or rice, cooked cereal, applesauce, and bananas. Eat slowly and avoid foods that are hard to digest or may irritate your stomach, such as foods with acid (like tomatoes or oranges), spicy or fatty food, meats, and raw vegetables. You may be able to go back to your normal diet in a few days.
• If you have cramps or stomach pain, it may help to put a hot water bottle or heating pad on your stomach. Cover the hot water bottle with a towel or set the heating pad on low so you don’t burn your skin.
• Don’t take 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. These risks increase with age. Read the label and take as directed. Unless recommended by your healthcare provider, you should not take this medicine for more than 10 days.

Ask your healthcare provider:

• How and when you will hear your test results
• How long it will take to recover
• What activities you should avoid and when you can return to your normal activities
• How to take care of yourself at home
• What symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup.

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.
• Avoid exposure to your partner’s anus, rectum, or bowel movements during sexual activity.
• 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.