CDC: What is Giardiasis?


Giardiasis is a diarrheal disease caused by the microscopic parasite Giardia duodenalis (or “Giardia” for short). Once a person or animal has been infected with Giardia, the parasite lives in the intestines and is passed in stool (poop). Once outside the body, Giardia can sometimes survive for weeks or even months. Giardia can be found in every region of the United States and around the world.

How do you get giardiasis and how is it spread?

You can get giardiasis if you swallow the Giardia parasite (germ). Giardia—or poop from people or animals infected with Giardia—can contaminate anything it touches. Giardia spreads very easily; even getting tiny amounts of poop in your mouth could make you sick.

Giardiasis can be spread by:

  • Swallowing unsafe food or water contaminated with Giardia germs
  • Having close contact with someone who has giardiasis, particularly in childcare settings
  • Traveling within areas that have poor sanitation
  • Exposure to poop through sexual contact from someone who is sick or recently sick with Giardia
  • Transferring Giardia germs picked up from contaminated surfaces (such as bathroom handles, changing tables, diaper pails, or toys) into your mouth
  • Having contact with infected animals or animal environments contaminated with poop

What are the symptoms of giardiasis?

Giardia infection (giardiasis) can cause a variety of intestinal symptoms, which include:

  • Diarrhea
  • Gas
  • Foul-smelling, greasy poop that can float
  • Stomach cramps or pain
  • Upset stomach or nausea
  • Dehydration

Symptoms of giardiasis generally begin by having 2 to 5 loose stools (poop) per day and progressively increasing fatigue. Other, less common symptoms include fever, itchy skin, hives, and swelling of the eyes and joints. Over time, giardiasis can also cause weight loss and keep the body from absorbing nutrients it needs, like fat, lactose, vitamin A, and vitamin B12. Some people with Giardia infections have no symptoms at all.

How long after infection do symptoms appear?

Symptoms of giardiasis normally begin 1 to 2 weeks after becoming infected.

How long will symptoms last?

Symptoms generally last anywhere from 2 to 6 weeks. In people with weakened immune systems (e.g., due to illness such as HIV), symptoms may last longer. Healthcare providers can prescribe the appropriate antiparasitic medications to help reduce the amount of time symptoms last.

Who is most at risk of getting giardiasis?

Anyone can become infected with Giardia. However, those at greatest risk are:

  • People in childcare settings
  • People who are in close contact with someone who has the disease
  • Travelers within areas that have poor sanitation
  • People who have contact with poop during sexual activity
  • Backpackers or campers who drink untreated water from springs, lakes, or rivers
  • Swimmers who swallow water from swimming pools, hot tubs, splash pads, or untreated recreational water from springs, lakes, or rivers
  • People who get their household water from a shallow well
  • People with weakened immune systems
  • People who have contact with infected animals or animal environments contaminated with poop

How is giardiasis diagnosed?

Contact your healthcare provider if you think you may have giardiasis. Your healthcare provider will ask you to submit stool (poop) samples to see if you are infected. Because it can be difficult to detect Giardia, you may be asked to submit several stool specimens collected over several days to see if you are infected.

What is the treatment for giardiasis?

Many prescription drugs are available to treat giardiasis. Although Giardia can infect all people, infants and pregnant women may be more likely to experience dehydration from the diarrhea caused by giardiasis. To prevent dehydration, infants and pregnant women should drink a lot of fluids while sick. Dehydration can be life-threatening for infants, so it is especially important that parents talk to their healthcare providers about treatment options for their infants.

My child does not have diarrhea but was recently diagnosed with giardiasis. My healthcare provider says treatment is not necessary. Is this correct?

Your child may not need treatment if they have no symptoms, though it is important to consider that their poop may remain a source of infection for other household members for an uncertain period of time. However, if your child does not have diarrhea but does have other symptoms, such as nausea or upset stomach, tiredness, weight loss, or a lack of hunger, you and your healthcare provider may need to consider treatment. The same is true if many family members are sick or if a family member is pregnant and unable to take the most effective medications to treat Giardia. Contact your healthcare provider for specific treatment recommendations.

Can I get giardiasis from my private well?

Giardia-contaminated poop can enter ground water through different ways, including sewage overflows, sewage systems that are not working properly, and polluted storm water. Wells may be more likely to be contaminated by poop after flooding, particularly if the wells are shallow, have been dug or bored, or have been covered by floodwater for long periods of time. Overused, leaky, or poorly maintained septic systems could contaminate nearby wells with germs from poop, including Giardia.

What can I do to prevent and control giardiasis?

To prevent and control Giardia infection, it is important to:

  • Wash your hands with soap and water during key times, especially:
    • before preparing food or eating, and
    • after using the bathroom or changing diapers.
  • Avoid eating food and drinking water that might be contaminated with Giardia germs.
    • Properly treat water from springs, lakes, or rivers (surface water) while backpacking or camping if no other source of safe water is available.
    • Avoid swallowing water from swimming pools, hot tubs, splash pads, and untreated water from springs, lakes, or rivers (surface water) while swimming.
    • Store, clean, and prepare fruits and vegetables properly.
  • Practice safe sex by reducing your contact with poop during sex or avoid having sex several weeks after you or your partner have recovered from giardiasis.

Can I get giardiasis from my pet?

The chances of people getting a Giardia infection from dogs or cats are small. The type of Giardia that infects humans is usually not the same type that infects dogs and cats. For more information, see Giardia and Pets.

Source: https://www.cdc.gov/parasites/giardia/general-info.html#anchor_1614258695587