Patient education: Giardia (The Basics)

What is Giardia? — 

This is an infection of the digestive system (figure 1). It can cause diarrhea, nausea, and stomach ache. It is very common.

What are the symptoms of Giardia? — 

Giardia infections do not always cause symptoms. Some people carry the parasite that causes Giardia without ever knowing it. When symptoms do happen, they can include:

●Diarrhea that begins suddenly and that can be watery at first

●Feeling ill

●Having bowel movements that are greasy and smell worse than usual

●Belly cramps, gas, and bloating

●Nausea or vomiting

●Weight loss

Should I see a doctor or nurse? — 

Maybe. See your doctor or nurse if you:

●Have severe diarrhea (diarrhea that happens many times in a day)

●Have severe belly pain

●Cannot eat or drink

●Have a fever higher than 100.4°F (38°C)

Young children and older adults with symptoms should see their doctor or nurse. That's because these groups can get dehydrated more easily than other people.

How is Giardia spread? — 

The infection can spread in 3 ways:

●From person to person – The parasite that causes Giardia lives in bowel movements of people who are infected. You can catch Giardia from another person if they do not wash their hands after a bowel movement and then touch you. The same is true for someone who changes a diaper for a child or an adult and then does not wash their hands. It is also possible to catch Giardia through any kind of anal sex (even if you use a condom).

●Through food – The parasite that causes Giardia can live on food. Cooking kills it. But if food is not cooked or not handled the right way, it can carry Giardia.

●Through water – The parasite that causes Giardia can live in water sources like streams or drinking wells. Also, people who camp and hike are at risk of getting Giardia if they drink water from lakes or streams without treating the water properly first.

Is there a test for Giardia? — 

Yes. If your doctor or nurse thinks that you might have Giardia, they will ask you for a sample of a bowel movement. The sample can be checked at the lab for Giardia and other infections that can cause the same symptoms.

How is Giardia treated? — 

Treatment involves taking an antibiotic medicine for several days. This usually gets rid of the infection and its symptoms. But sometimes, Giardia does not get better with the first round of antibiotics. If so, doctors usually suggest changing the type or dose of antibiotic, or increasing the length of treatment.

If you do not have symptoms of Giardia, you might not need antibiotics, even if the test shows that you have the infection. Some people with Giardia get better on their own without treatment. But children in day care and people who work with food should be treated for Giardia, even if they have no symptoms. This helps prevent the spread of infection.

How can I help prevent spreading Giardia? — 

The most important thing is to be clean. You should:

●Wash your hands with soap and water after using the bathroom, and teach children to do the same.

●Wash your hands with soap and water after changing diapers or after touching anyone who can't control their bowels.

●Throw away dirty diapers right away in sealed trash bins.

●Wash clothes that could have even small amounts of bowel movement on them.

●Try not to swallow water when swimming.

●Kill the germs and parasites in drinking water when traveling or hiking. You can do this by doing 1 of these things:

•Boil drinking water for at least 10 minutes at a hard boil.

•Add 5 drops of tincture of iodine to 4 cups of water, and wait 30 minutes. Tincture of iodine is a liquid you can buy at most pharmacies or camping goods stores. People also use it on cuts to kill germs. It is much better at killing Giardia than bleach.

•Use a good water-filtering system.

More on this topic

Patient education: Diarrhea in teens and adults (The Basics)
Patient education: Diarrhea in children (The Basics)
Patient education: Food poisoning (The Basics)

Patient education: Giardia (Beyond the Basics)
Patient education: Acute diarrhea in adults (Beyond the Basics)
Patient education: Chronic diarrhea in adults (Beyond the Basics)
Patient education: Acute diarrhea in children (Beyond the Basics)
Patient education: Foodborne illness (food poisoning) (Beyond the Basics)