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Giardia is a tiny parasite (germ) that causes the diarrheal disease giardiasis. Giardia is found on surfaces or in soil, food, or water that has been contaminated with feces (poop) from infected people or animals.

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.

Giardia can be found in every region of the United States and around the world. In the United States, Giardia infection is the most common intestinal parasitic disease, and it affects more than 1 million people per year. Certain factors can increase your risk of getting sick from Giardia:

  • Children are at much higher risk for Giardia infection than adults and have higher infection rates.
  • Giardia infection rates tend to rise in late summer in the United States.
  • Travelers to areas with poor sanitation are more likely to get infected with Giardia.

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 Giardi
  • 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

  • Practice good hand hygiene.
  • Avoid water that might be contaminated.
  • Avoid food that might be contaminated.
  • Practice safer sex.
  • Clean and disinfect.

Giardiasis is not a reportable disease in Oklahoma.

If you have diarrhea, drink a lot of fluids while sick to avoid dehydration (loss of fluids).

Infants and pregnant women may be more likely to become dehydrated from diarrhea caused by a Giardia infection. Dehydration can be life-threatening for infants, so it is especially important to talk to a doctor about treatment options if your infant is sick.

Discuss treatment options with your doctor.